D.N.T. stands for Dysembryoplastic Neuroepithelial Tumor-Like Neoplasm. These
rare brain tumors occur in children and young adults and commonly present
in the midline region of the septum pellucidum of the brain. Patients present
with the usual symptoms of a mass lesion in the brain with headache, nausea
and vomiting, and visual disturbances. These tumors appear to behave in a
benign fashion.
| PATHOGENESIS |
CHARACTERIZATION |
| APOPTOSIS |
|
|
Bcl-2, bcl-x, and bax expression in dysembryoplastic neuroepithelial
tumors.
Prayson RA.
Department of Anatomic Pathology, Cleveland Clinic Foundation, OH
44195, USA. |
Clin Neuropathol 2000 Mar-Apr;19(2):57-62 Abstract quote
BACKGROUND: Bcl-2, bcl-x and bax are regulatory proteins which are
variably expressed in brain tissue and are known to be involved in the
regulation of apoptosis; bcl-2 and bcl-x inhibit apoptosis and bax generally
promotes apoptosis. This study is a retrospective clinicopathologic
and immunohistochemical review of 18 dysembryoplastic neuroepithelial
tumors (DNTs), specifically looking for evidence of aberrant expression
of apoptosis regulatory proteins which may promote the survival of one
or more of the cellular constituents of the tumor.
MATERIALS AND METHODS: Eighteen patients (11 males) with DNTs comprise
the study group. Patients at the time of surgery ranged in age from
2.1-52 years (mean 16.1 years). Mean seizure duration prior to surgery
was 6.4 years (n = 16 patients). Sixteen patients were alive with markedly
reduced or no seizures at a mean postsurgical follow-up interval of
63 months; 2 patients were lost to follow-up.
RESULTS: All tumors were characterized by an admixture of oligodendroglial
cells, neurons and astrocytic cells, focally arranged against a microcystic
background. Coexistent cortical dysplasia was noted in 14 evaluable
cases. Mitotic figures were rarely noted in 2 tumors. MIB-labeling indices
ranged from 0-0.6 (mean 0.2). Astrocytes which were part of the tumor
stained with all three antibodies in all cases. The oligodendroglial-like
cells of DNT stained positively for bcl-2 in 2/17 tumors, bcl-x in 10/17
tumors, and bax in 12/17 tumors. The neuronal cell component of the
DNT stained positively with bcl-2 in 15/17 tumors, bcl-x in 5/17 tumors,
and bax in 8/17 tumors.
CONCLUSION: Aberrant expression of apoptosis-associated proteins, similar
to what has been previously described in gangliogliomas (another epilepsy-related,
dysplasia-associated tumor), may play a role in the pathogenesis of
DNT. |
| CHROMOSOMAL ABNORMALITIES |
|
|
Chromosome 1p allelic loss by fluorescence in situ hybridization is
not observed in dysembryoplastic neuroepithelial tumors.
Prayson RA, Castilla EA, Hartke M, Pettay J, Tubbs RR, Barnett
GH.
Department of Neurological Surgery, Cleveland Clinic Foundation,
OH 44195, USA.
|
Am J Clin Pathol 2002 Oct;118(4):512-7 Abstract quote
Differentiation of dysembryoplastic neuroepithelial tumor (DNT) from
cystic low-grade oligodendroglioma, particularly in a limited biopsy
orfragmented specimen, may be impossible. Research has shown that allelic
loss of chromosome 1p is a relatively common finding in oligodendrogliomas.
Little is known about chromosome 1p status in DNT.
We retrospectively evaluated 14 DNTs for loss of heterozygosity (LOH)
on chromosome 1p by fluorescence in situ hybridization (FISH) and compared
the results with 1p FISH analysis in 57 low-grade oligodendrogliomas
(World Health Organization grade II). The 14 DNTs arose in 8 females
and 6 males (mean age, 20.9 years at the time of surgery). All 14 DNTs
were 1p intact by FISH analysis. The 57 low-grade oligodendrogliomas
arose in 31 males and 26 females (mean age, 43.2 years). LOH on chromosome
1p was present in 31 (54%) of 57 tumors; the remaining 26 tumors were
1p intact. LOH on chromosome 1p is not a feature of DNTs.
LOH on chromosome 1p may be a useful differential diagnostic feature
(favoring oligodendroglioma) in a subset of cases in which specimen
fragmentation or size raises the differential diagnosis of DNT vs oligodendroglioma. |
| GLUTAMATE |
|
|
Dysembryoplastic neuroepithelial tumour (DNT). Is the mechanism of seizures
related to glutamate? An immunohistochemical study.
Adamek D, Korzeniowska A, Morga R, Lopatka P, Jelenska-Szygula I,
Danilewicz B.
Department of Neuropathology, Institute of Neurology, Jagiellonian
University, Medical College, Krakow, Poland. |
Folia Neuropathol 2001;39(2):111-7 Abstract quote
Dysembryoplastic neuroepithelial tumour (DNT) is a rare low-grade,
mixed neuronal and glial tumour, usually associated with pharmacologically
intractable, complex partial or generalised seizures which date from
childhood. The prognosis after surgery is favourable.
We present a classic case of DNT occurring in an 18-year-old male,
who presented simple partial seizures without signs of raised intracranial
pressure. CT and MR demonstrated focal mass located in the right temporal
lobe. Histologically there were found the features of a typical DNT
architecture with mixed cellular composition. The response to surgery
was excellent. The tumour has not recurred, and the control of seizures
remained good. Immunostaining for glutamate receptor GluR-2 showed stronger
immunopositivity in neurones dispersed within the tumour and especially
in margins of lesion as compared with apparently normal cerebral cortex.
The expression of both excitatoryamino acid transporterproteins EAAT1
and EAAT2 was weaker then in normal cortex and uneven. This perhaps
may explain the mechanism of seizures (elevated glutaminergic stimulation),
and may suggest the excitotoxic damage of neurones. |
| LABORATORY/RADIOLOGIC/OTHER TESTS |
CHARACTERIZATION |
| Radiographs |
|
| CT scan and MRI |
Tumors extended into the lateral ventricles from the septal region
and obstructed the foramen of Monro with varying degrees of hydrocephalus
Lobular, well-delineated, hypointense to brain on T1-weighted magnetic
resonance imaging, and hyperintense on T2-weighted images
Uniformly nonenhancing or showed only minimal peripheral enhancement
|
|
Dysembryoplastic neuroepithelial tumors: MR appearance.
Koeller KK, Dillon WP.
Department of Radiology, University of California, San Francisco
94143-0628.
|
AJNR Am J Neuroradiol 1992 Sep-Oct;13(5):1319-25 Abstract
quote
PURPOSE: Dysembryoplastic neuroepithelial tumor (DNT) is a newly described,
pathologically benign tumor arising within the supratentorial cortex
and having a 100% association with partial complex seizures. We reviewed
the MR appearance of the brains of six patients with DNT, without and
with administration of gadolinium-DTPA, emphasizing the clinical and
radiologic features.
METHODS: The MR images in six patients (five male, one female) with
pathologically proved DNT were reviewed. Five had partial complex seizures
and one had partial simple seizures. Age at onset of partial seizures
ranged from 2 to 19 years. Scans were obtained with conventional T1
and T2 weighting without and with the administration of gadolinium-DTPA.
All patients had craniotomies for medically refractory seizures and
pathologic examination of all specimens was available for review.
RESULTS: MR demonstrated a focal cortical mass in all patients. Five
were located in the temporal lobe and one was located within the occipital
lobe. Two showed enhancement with gadolinium-DTPA. Calcification occurred
in one lesion. Common features included very low signal intensity on
T1-weighted images and high signal on T2-weighted images, similar to
cerebrospinal fluid. Proton density images demonstrated slightly higher
signal intensity in the lesion than cerebrospinal fluid. The margin
of the tumor is well-circumscribed and may remodel the adjacent calvarium.
CONCLUSIONS: DNT, a newly described pathologic entity resulting in
chronic, often medically, intractable seizures, has characteristic features
on MR that allow it to be suggested in the differential diagnosis. These
lesions may simulate benign cysts; however, increased signal intensity
on proton density images should prompt further investigation in the
proper clinical setting. Differentiation from low-grade astrocytomas
and ganglioglioma is not possible by MR.
|
|
Dysembryoplastic neuroepithelial tumors: MR findings.
Kuroiwa T, Kishikawa T, Kato A, Ueno M, Kudo S, Tabuchi K.
Department of Radiology, Saga Medical School, Japan.
|
J Comput Assist Tomogr 1994 May-Jun;18(3):352-6 Abstract
quote
OBJECTIVE: We report MR findings in three patients with dysembryoplastic
neuroepithelial tumor (DNT), which is a recently described benign tumor
in childhood or young adolescents.
MATERIALS AND METHODS: The MR studies of three patients with surgically
proven DNT were reviewed. All cases presented with partial complex seizures.
Axial and coronal T1- and T2-weighted MR imaging of the head was performed
using a 1.5 T MR unit. T1-weighted imaging after Gd-DTPA was also performed.
RESULTS: The tumors were located mainly in the cortical to subcortical
area with very little perifocal mass effects on MR imaging. They were
essentially hypointense on T1-weighted imaging and hyperintense well-demarcated
mass on T2-weighted imaging and retained a thick gyrus-like configuration
within the lesions. None of them exhibited contrast enhancement after
administration of Gd-DTPA.
CONCLUSION: Differentiation of DNT from gangliogliomas or other low
grade gliomas is possible using these MR features and is important because
DNT does not recur after epilepsy surgery, therefore postoperative radiation
and chemotherapy are not needed.
|
|
Dysembryoplastic neuroepithelial tumor: radiological findings (including
PET, SPECT, and MRS) and surgical strategy.
Lee DY, Chung CK, Hwang YS, Choe G, Chi JG, Kim HJ, Cho BK.
Department of Neurosurgery, Seoul National University College of
Medicine, Korea.
|
J Neurooncol 2000 Apr;47(2):167-74 Abstract quote
In order to elucidate the radiological features of dysembryoplastic
neuroepithelial tumor (DNT), and to clarify the optimal surgical strategy
for this tumor, the authors retrospectively analyzed 20 cases of DNT
treated at our institution.
Magnetic resonance (MR) imaging (all cases), 18F-fluorodeoxyglucose
positron emission tomography (18F-FDG PET) (eight cases), ictal/interictal
Tc99m-HMPAO single photon emission computed tomography (SPECT) (seven
and five cases respectively) and proton magnetic resonance spectroscopy
(1H MRS) (one case) were performed preoperatively. Invasive monitoring/intraoperative
electrocorticography (ECoG) was performed in four cases in order to
determine the epileptogenic zone.
A well-demarcated lobulating tumor located in the cortical with/without
subcortical area was the typical MR finding. 18F-FDG PET showed glucose
hypometabolism in all cases. Ictal Tc99m-HMPAO SPECT showed hyperperfusion
of the lesion in three cases and interictal Tc99m-HMPAO SPECT showed
hypoperfusion of the lesion in one case. 1H MRS showed nonspecific findings.
Gross total resection was performed in all cases. Histologically, associated
cortical dysplasia was found in 11 cases. The mean duration of follow-up
after surgery was 37.9 months, and the overall seizure free rate was
90%.
Follow-up MR imaging was performed in 14 cases (mean duration of follow-up:
21.6 months) and showed no recurrence of tumor in any of these cases.
Invasive monitoring/intraoperative ECoG and the presence of cortical
dysplasia showed no significant relationship with seizure control rate
(p = 1.25 and p = 1.62 respectively).
|
| PET SCAN |
|
|
Positron emission tomography using [18F] fluorodeoxyglucose and [11C]
l-methionine to metabolically characterize dysembryoplastic neuroepithelial
tumors.
Kaplan AM, Lawson MA, Spataro J, Bandy DJ, Bonstelle CT, Moss SD,
Manwaring KH, Reiman EM.
Division of Neurology, Phoenix Children's Hospital/Good Samaritan
Regional Medical Center, AZ 85006, USA.
|
J Child Neurol 1999 Oct;14(10):673-7 Abstract quote
Dysembryoplastic neuroepithelial tumors are unique and benign congenital
tumors occurring frequently in children and adolescents. Differentiation
from other low-grade tumors is important for management.
Five patients with confirmed dysembryoplastic neuroepithelial tumors
were studied with positron emission tomography using glucose and protein
metabolic uptake in an attempt to categorize these tumors metabolically.
Functional brain mapping also was obtained to aid in operative management.
Results of the study conclude that dysembryoplastic neuroepithelial
tumors, although having similar neuroimgaing characteristics to other
low-grade tumors, are distinguished by a unique metabolic profile. They
are inactive tumors with no significant glucose or protein metabolic
activity.
The combination of preoperative positron emission tomographic metabolic
studies with functional brain mapping allowed for prediction of tumor
type, defined eloquent areas of cortical function, and improved approach
and resection of the tumors with minimal risk of neurologic impairment.
|
| CLINICAL VARIANTS |
CHARACTERIZATION |
| GENERAL |
|
|
Dysembryoplastic neuroepithelial tumor. Features in 16 patients.
Raymond AA, Halpin SF, Alsanjari N, Cook MJ, Kitchen ND, Fish DR,
Stevens JM, Harding BN, Scaravilli F, Kendall B, et al.
Institute of Neurology, National Hospital for Neurology and Neurosurgery,
London, UK.
|
Brain 1994 Jun;117 ( Pt 3):461-75 Abstract quote
Dysembryoplastic neuroepithelial tumour (DNT) is a newly recognized
brain mass lesion with distinctive pathological features and a favourable
prognosis.
We reviewed the clinical, electroencephalographic, neuroimaging and
pathological features of 16 patients with DNT who underwent surgery;
only one patient did not have epilepsy. Mean age at seizure onset was
9.5 years (range: 1 week to 30 years) and surgery 17 years (range: 7
months to 37 years). The mean verbal IQ was 94.6 (range: 79-110) and
performance IQ 105 (range: 79-130) (n = 10). The EEG was abnormal in
all cases reviewed (n = 13): localized slow activity was seen in 12
and interictal spiking in 10 patients, being less extensive than or
concordant with the lesion in three and more extensive than or distant
to the lesion in seven. X-ray CT was normal in three out of 11 patients.
Magnetic resonance imaging provided detailed anatomical information:
the lesion was predominantly intracortical, although in six patients,
there was also white matter involvement. The lesion involved the temporal
lobe in all but one patient where it was in the cingulate gyrus. Of
the temporal lobe cases, MRI showed that the lesion involved, or was
in close proximity to, mesial temporal structures in 11 out of 14 patients.
Other magnetic resonance features included: circumscribed hyperintensity
on long TE/TR images (10 patients), hypointensity on short TR images
(12 patients), and cyst formation (five patients). Calcification was
seen on CT in four patients. Post surgical follow-up ranged from 8 to
30 months (mean 16.2 months): 12 patients are seizure free and two have
a > 80% reduction in seizure frequency (n = 14).
Histopathological characteristics included a heterogeneous composition
in all cases, calcification (13 cases), dysplastic features (12 cases)
and isolated foci of subpial spread (five cases). The presence of occasional
mitoses in 12 cases and immunoreactivity to the proliferating cell nuclear
antigen in six cases indicate that these lesions have cellular proliferative
activity and that there may be a need to follow these patients postoperatively.
|
|
Dysembryoplastic neuroepithelial tumor: morphological, immunocytochemical,
and deoxyribonucleic acid analyses in a pediatric series.
Taratuto AL, Pomata H, Sevlever G, Gallo G, Monges J.
Instituto de Investigaciones Neurologicas Raul Carrea, Fundacion
para la Lucha contra las Enfermedades Neurologicas de la Infancia, Buenos
Aires, Argentina.
|
Neurosurgery 1995 Mar;36(3):474-81 Abstract quote
Overtreatment by radiotherapy and/or chemotherapy for central nervous
system tumors in infancy and childhood may be deleterious, so the recognition
of surgically curable clinicopathological entities is mandatory.
The dysembryoplastic neuroepithelial tumor is a complex multinodular
lesion consisting of glial nodules, associated with a specific glioneuronal
element and/or with focal cortical dysplasia, and occurring in young
patients presenting with intractable, mostly complex partial, seizures
without neurological deterioration. We report on 14 patients; 9 were
from a series of 600 pediatric patients with intracranial central nervous
system tumors studied at a single institution from 1988 to 1993, and
5 were referred from other pediatric hospitals. Six tumors were frontal,
six were temporal, one was parietal, and one was occipitoparietal. Computed
tomographic scans disclosed hypodense lesions with cystic appearances
in 4 patients and slight focal postcontrast enhancements in only 2 patients,
whereas magnetic resonance imaging, available for 7 of 14 patients,
showed hypointense lesions in T1-weighted images and hyperintense lesions
in T2-weighted images. Deformities of the overlying cranium were also
observed in five patients.
The age range at the time of surgery (excluding a 20-year-old male
patient who underwent surgery at the main pediatric hospital) was 2.6
to 13 years, with a mean of 6.68 years. The male to female patient ratio
was 10:4, and the duration of symptoms was 0.2 to 6 years.
|
|
Dysembryoplastic neuroepithelial tumor.
Cabiol J, Acebes JJ, Isamat F.
Department of Neurosurgery, Ciutat Sanitaria y Universitaria de
Bellvitge, Universitat de Barcelona, Torras i Pujalt 1, E-08022 Barcelona,
Spain
|
CRITICAL REVIEWS IN NEUROSURGERY 1999 Mar 24;9(2):116-125
Abstract quote
Dysembryoplastic neuroepithelial tumors (DNTs) were first described
in 1988. A DNT is a cortical tumor that produces enlargement of a gyrus,
forming a megagyrus that exceeds the normal thickness of the cortex.
This tumor is generally seen in young patients with a long-standing
history of drug-resistant and disabling seizures mostly of the complex
partial type. No neurological deficits are found between the interictal
periods in the majority of the reported cases. A general agreement exists
over the clinical and radiological manifestations of a DNT as well as
the benign biological behavior. Two pathological variants of DNT have
been recognized: the single form, composed only of the so-called specific
glioneuronal element, and the complex form that additionally shows glial
nodules and foci of cortical dysplasia. Nevertheless, and despite the
benign biological course, nuclear atypias, cellular monstruosities,
foci of necrosis and mitosis can also be found. Surgical eradication
of the tumor will usuallly have a good prognosis, without recurrences
and with a positive control to seizure-free clinical outcome. Controversy
continues to exist over a hamartomatous or a neoplastic origin of this
lesion. The DNT has been placed among the neuronal and mixed neuronal-glial
neoplasms in the revised World Health Organization (WHO) brain tumor
classification, a category that includes the gangliogliomas and the
central neurocytomas.
Ultrastructural studies and immunostaining techniques may suggest that
these three lesions represent different spectrums of the same condition.
This paper reviews the most recent publications to offer a better understanding
of DNTs and their implications in diagnosis and management.
|
| VARIANTS |
|
| CEREBELLUM |
|
|
Dysembryoplastic neuroepithelial tumour of the cerebellum.
Kuchelmeister K, Demirel T, Schlorer E, Bergmann M, Gullotta F.
Institut fur Neuropathologie der Universitat, Munster, Germany.
|
Acta Neuropathol (Berl) 1995;89(4):385-90 Abstract quote
A case of dysembryoplastic neuroepithelial tumour of the cerebellum
occurring in a 28-year-old woman is presented. The lesion extended from
the cortex of the inferior vermis upwards into the white matter.
Histologically, it exhibited areas of microcystic cerebellar astrocytoma
and glial regions with hamartomatous blood vessels as well as areas
with oligodendrocyte-like cells (OLC) with a delicate, fibrillary stroma
lying in a mucinous, often microcystic matrix. The OLC showed prominent
rosette formation and immunohistochemical features suggesting neuronal,
i.e. granule cell, differentiation.
|
| INTRACEREBRAL HEMORRHAGE |
|
|
Spontaneous intralesional haemorrhage in dysembryoplastic neuroepithelial
tumours: a series of five cases.
Thom M, Gomez-Anson B, Revesz T, Harkness W, O'Brien CJ, Kett-White
R, Jones EW, Stevens J, Scaravilli F.
Department of Neuropathology, National Hospital for Neurology and
Neurosurgery, London.
|
J Neurol Neurosurg Psychiatry 1999 Jul;67(1):97-101 Abstract
quote
Five patients with dysembryoplastic neuroepithelial tumour (DNT) showing
extensive secondary haemorrhage, a finding not previously associated
with these neoplasms, are described.
The clinical presentations, neuroimaging findings, and histopathological
features of these patients are reviewed. One patient, a previously asymptomatic
12 year old girl, presented with an acute intracerebral haemorrhage
into a DNT. A further four young adults with histories of intractable
partial and generalised seizures dating from childhood showed significant
chronic haemorrhages within DNT, the MRI appearances in one patient
giving a false impression of a cavernoma.
Histopathology disclosed vascular abnormalities within these tumours
which, together with other factors discussed, may have predisposed these
tumours to haemorrhage.
|
| MULTIFOCAL |
|
|
Dsyembryoplastic neuroepithelial tumour with discrete bilateral multifocality:
further evidence for a germinal origin.
Whittle IR, Dow GR, Lammie GA, Wardlaw J.
Department of Clinical Neuroscience, Western General Hospital, Edinburgh,
UK.
|
Br J Neurosurg 1999 Oct;13(5):508-11 Abstract quote
We report the case of a middle aged woman who developed refractory
complex partial seizures in her early twenties. She had a right coloboma
and neurological examination was normal. Neuropsychological assessments
revealed mild impairments of non-verbal memory, and visuospatial and
constructional difficulties.
Serial CT and MRI showed multiple nodular abnormalities in her mid-brain,
diencephalon, subependymal region and both mesial temporal lobes. EEG
recording revealed a right medial temporal focus. She underwent en bloc
temporal lobectomy. The surgical pathology revealed mesial temporal
dysembryoplastic neuroepithelial tumour (DNET) in association with extensive,
contiguous neocortical dysplasia. The proliferation marker MIB-1 revealed
up to 2% labelling in tumour areas resembling conventional oligodendroglioma.
In the two years since surgery she has been seizure free and the remaining
MR brain abnormalities have not changed. The very unusual centripetal
MRI pattern of discrete multifocal lesions with the characteristic T1
and T2 features of DNET would support the dysembyroplastic germinal
origin that was proposed by Daumas-Duport et al. (1988) in their original
description of the lesion.
The neuroradiological, neuropathological and clinical features of this
case are compared with the two previous cases of multifocal DNET.
|
| HISTOLOGICAL TYPES |
CHARACTERIZATION |
| GENERAL |
Lobular microcystic appearance with relatively well-defined borders
Multiple, discrete microscopic nodules with the principal tumor cells
with uniformly round and hyperchromatic nuclei, and prominent perinuclear
clearing resembling oligodendrocytes
Oligodendrocyte-like cells (OLCs) were clustered tightly about perivascular
spaces, in some instances forming an alveolar or rosette-like pattern
Specific glioneuronal element with tumor cells arranged parallel to
fibrillar zones in a well-defined linear array
Neurons appeared to be part of the lesions and appeared to float in
a mucoid or finely fibrillar background
None of the neurons were binucleate or displayed dysplastic features.
Perineuronal satellitosis was absent
No glomeruloid vascular proliferation, Rosenthal fibers, or eosinophilic
granular bodies were noted
Mitotic figures were absent to rare
|
|
Dysembryoplastic neuroepithelial tumours.
Daumas-Duport C.
Department of Pathological Anatomy, Sainte-Anne Hospital,
Paris, France.
|
Brain Pathol 1993 Jul;3(3):283-95 Abstract quote
Dysembryoplastic neuroepithelial tumours (DNTs) are a group of supratentorial
cortical benignant lesions that superficially resemble mixed oligo-astrocytomas,
oligodendrogliomas or astrocytomas. Clinically these tumours are associated
with partial seizures beginning before the age of 20 years, with no
neurologic deficit and no stigmata of phacomatosis.
In the revised WHO classification, DNTs have been incorporated among
the category of neuronal and mixed neuronoglial tumours. This classification
describes a histologic variant characterized by the following criteria:
cortical location, multinodular architecture--the nodule being made
of multiple variants looking like astrocytomas, oligodendrogliomas or
oligo-astrocytomas, foci of dysplastic cortical disorganization and
the presence of a glioneuronal element showing a columnar structure
perpendicular to the cortical surface. A study of 14 cases for which
only a specific glioneuronal element could be identified demonstrated
that this specific element is sufficient for diagnosing DNTs and that
the spectrum of DNTs includes a simple form with a unique glioneuronal
element.
Preoperative imaging follow-up data, in the series of 23 simple and
complex forms, indicated that DNTs are perfectly stable. However, these
tumours may show a high MIB 1 labeling index.
|
|
Dysembryoplastic neuroepithelial tumors: nonspecific histological forms
-- a study of 40 cases.
Daumas-Duport C, Varlet P, Bacha S, Beuvon F, Cervera-Pierot
P, Chodkiewicz JP.
Department of Pathology, Sainte-Anne Hospital, Cochin
Port-Royal University, Paris, France.
|
J Neurooncol 1999 Feb;41(3):267-80 Abstract quote
OBJECTIVE: To demonstrate that DNTs include a large morphological spectrum
of tumors that cannot be histologically distinguished from conventional
categories of gliomas.
METHODS: All tumors from patients who underwent epilepsy surgery in
Sainte-Anne hospital (Paris) that histologically resembled gliomas and
did not conform to current histological criteria for DNTs or gangliogliomas
were entered in the study.
RESULTS: According to the WHO histological classification, the 40 tumors
resembled: pilocytic astrocytomas (4 cases), astrocytomas (16 cases),
anaplastic astrocytoma (1 case), oligodendrogliomas (10 cases), oligo-astrocytomas
(8 cases) or anaplastic oligo-astrocytomas (1 case). However foci of
cortical dysplasia could be observed in 47% of the cases. Clinical presentation
and imaging features were strikingly similar to that observed in typical
DNTs. Although surgical removal was incomplete in 28% of the cases and
none of the patients underwent chemo or radiotherapy, none of the tumors
recurred (mean follow-up: 7 years). Moreover, serial preoperative imaging
in 26 patients (mean follow-up: 4.5 years) demonstrated that these lesions
were perfectly stable.
CONCLUSIONS: Whatever the histological appearance of a glial tumor,
the diagnosis of DNT must be considered when all the following criteria
are associated: (1) partial seizures, with or without secondary generalization,
beginning before the age 20 years, (2) no neurological deficit or stable
congenital deficit, (3) cortical topography of the lesion as better
demonstrated by MRI and (4) no mass effect on imaging.
|
|
Histological heterogeneity of dysembryoplastic neuroepithelial tumour:
identification and differential diagnosis in a series of 74 cases.
Honavar M, Janota I, Polkey CE.
Department of Neuropathology, Institute of Psychiatry,
King's Heath Trust, London, UK.
|
Histopathology 1999 Apr;34(4):342-56 Abstract quote
AIMS: In a retrospective study of resected specimens from 416 patients
being treated for long-standing epilepsy, 74 cases of dysembryoplastic
neuroepithelial tumour (DNT) were encountered that were all characteristically
composed of small round oligodendroglia-like cells (OLC), astrocytes
and mature neurones in varying proportions. The architectural patterns,
histological, immunohistochemical and ultrastructural features and results
of cell proliferation studies and postoperative follow-up are described
to facilitate the identification of DNT and to differentiate it from
other intrinsic neoplasms that commonly present with seizures.
METHODS AND RESULTS: The tumours presented with early onset of seizures,
at a median age of 7 years, without the signs of raised intracranial
pressure. A majority of the lesions were located in the temporal lobe
(n = 59), with fewer cases in the frontal (n = 8), parietal (n = 6)
and occipital lobes (n = 1), and ranged in size from 10 to 70 mm; 33
were cystic. Histologically three types could be distinguished, multinodular,
solitary nodular and diffuse. The first type (37.8%) had the features
of a typical DNT with multinodular architecture and mixed cellular composition.
The second type (33.8%) consisted of a solitary nodule, while the third
(28.4%) was a diffuse tumour, both composed of a similar mixture of
cells as the multinodular DNT. The lesions were seen in the neocortex
and white matter and tumours in the temporal lobe often involved the
amygdala and hippocampus. The presence of myxoid matrix, microcystic
change, calcification and leptomeningeal involvement were common. Dysplastic
neurones at the periphery of the tumour and abnormalities in cortical
lamination in the adjacent neocortex were found in about one-third of
the resections. Rare mitotic figures were encountered in eight of the
tumours and necrosis was found in two. Immunocytochemistry for glial
fibrillary acidic protein (GFAP) and neuronal markers neuron-specific
enolase, synaptophysin and neurofilament (RT 97) assists in establishing
the diagnosis, highlighting the astrocytic and neuronal components,
and the OLC, by the absence of expression of GFAP. Electron microscopy
showed that in some cases OLC show neuronal differentiation. Although
the proliferating cell nuclear antigen labelling index varied between
0 and 45.5%, 20 of the 51 tumours stained failed to express the antigen,
in keeping with the indolent nature of this neoplasm. The response to
surgery was excellent; none of the tumours have recurred, and the control
of seizures remained good.
CONCLUSIONS: Despite some histological heterogeneity, the clinical
and pathological features and indolent biological behaviour indicate
that these tumours constitute a single distinct entity. The spectrum
of morphological appearances of DNT is broader than has been previously
reported, the recognition of which is needed to avoid unnecessary neoadjuvant
therapy.
|
|
Dysembryoplastic neuroepithelial tumor-like neoplasm of the septum pellucidum:
a lesion often misdiagnosed as glioma: report of 10 cases.
Baisden BL, Brat DJ, Melhem ER, Rosenblum MK, King
AP, Burger PC.
Department of Pathology, Johns Hopkins University
School of Medicine, Baltimore, Maryland 21287, USA.
|
Am J Surg Pathol 2001 Apr;25(4):494-9 Abstract quote
The authors report a series of 10 low-grade neoplasms arising in the
midline anteriorly in the region of the septum pellucidum with many
of the histologic features of dysembryoplastic neuroepithelial tumor
(DNT).
The patients (five female, five male) ranged in age from 6 to 35 years
(mean age, 21.5 years). The most common presenting symptoms were headache,
nausea and vomiting, and visual disturbances. Radiographically, the
tumors extended into the lateral ventricles from the septal region and
obstructed the foramen of Monro. Varying degrees of hydrocephalus were
present. The lesions were lobular, well-delineated, hypointense to brain
on T1-weighted magnetic resonance imaging, and hyperintense on T2-weighted
images. They were uniformly nonenhancing or showed only minimal peripheral
enhancement. The tumors, in aggregate, had the histologic features of
DNT. These included a mucin-rich background, oligodendrocyte-like cells,
"floating neurons," and a "specific glioneuronal element."
Seven patients underwent gross total resection and two underwent subtotal
resection. No patients received adjuvant chemotherapy or radiotherapy.
On follow-up (n = 6; median, 14 months), all tumors had either not recurred
or were radiologically stable. On the basis of both neuroimaging and
histopathology, DNT-like lesions should be considered in the differential
diagnosis of midline intraventricular tumors in children and young adults.
Distinction from more aggressive neoplasms is essential because these
tumors appear to behave in a benign fashion.
|
|
Dysembryoplastic neuroepithelial tumors: report of 10 cases from a center
where epilepsy surgery is not done.
Tatke M, Suri VS, Malhotra V, Sharma A, Sinha S, Kumar
S.
Department of Pathology, G.B Pant Hospital, New Delhi,
India.
|
Pathol Res Pract 2001;197(11):769-74 Abstract quote
Dysembryoplastic neuroepithelial tumor (DNT) is a recently recognized
tumor entity with distinctive clinicopathological features and an excellent
long-term prognosis.
We report 10 cases of DNT out of neurosurgical specimens sent for histopathological
examination since 1994. Epilepsy surgery is not done at our center,
and all the cases were sent with a clinical diagnosis of glioma. On
histopathological examination, all the 10 cases contained the specific
glioneuronal element. In 6 cases, glial nodules were noted in addition.
This study therefore reports 4 cases of simple DNT and 6 cases of complex
DNT. There was no nuclear atypia or mitosis in any of the cases. Proliferative
index by PCNA varied from negative to <1%.
It is very important to recognize this entity, as surgery cures the
patient, and radiotherapy or chemotherapy is not required.
|
| VARIANTS |
|
| GANGLIOGLIOMA |
|
|
Composite ganglioglioma and dysembryoplastic neuroepithelial tumor.
Prayson RA.
Department of Anatomic Pathology, Cleveland Clinic Foundation, Ohio
44195, USA.
|
Arch Pathol Lab Med 1999 Mar;123(3):247-50 Abstract quote
Both ganglioglioma and dysembryoplastic neuroepithelial tumors are
well-recognized glial-neuronal neoplasms associated with chronic epilepsy
and cortical dysplasia (neuronal migration abnormalities).
The exact relationship between these 2 glial-neuronal tumors continues
to be debated. This article reports a case of a composite ganglioglioma
and dysembryoplastic neuroepithelial tumor occurring in a 36-year-old
woman in the left temporal lobe region. The resection histologically
demonstrated distinct areas of ganglioglioma and dysembryoplastic neuroepithelial
tumor. A focal area of cortical dysplasia is also identified. The MIB-1
labeling indexes in both components were low (<1% of tumor cell nuclei).
The coexistence of these 2 lesions and cortical dysplasia suggest a
possible etiologic relationship between these 2 tumors.
|
| MALIGNANT |
|
Malignant transformation of a dysembryoplastic neuroepithelial tumor
after radiation and chemotherapy.
Rushing EJ, Thompson LD, Mena H.
|
Ann Diagn Pathol. 2003 Aug;7(4):240-4. Abstract quote
We describe a case of anaplastic astrocytoma in a 14-year-old boy
arising at the site of a dysembryoplastic neuroepithelial tumor (DNT)
3 years after combined radiation and chemotherapy.
The subtotally excised
superficial right temporoparietal tumor was originally diagnosed as
mixed oligoastrocytoma in 1974; the patient was treated with radiation
therapy postoperatively. One year later he underwent a craniotomy to
remove cyst fluid and no change was reported in the size of the residual
tumor. Postoperatively, he received a 6-week course of chemotherapy
(lovustine, CCNU). He remained clinically and radiographically stable
until 3 years later, when seizure activity returned and imaging studies
were consistent with tumor recurrence. He was lost to follow-up until
1986, when records showed that he had died.
Review of the initial biopsy
showed cortical fragments containing abundant calcifications and multinodular
structures typical of the complex form of DNT, in addition to specific
glioneuronal elements. The Ki-67 labeling index ranged from 0.1% to
3% focally. The specimen from the third surgery showed an anaplastic
astrocytoma (Ki-67 up to 12%) and morphologic features characteristic
of radiation effect. This is the first documented case of malignant
transformation of DNT following radiation and adjuvant chemotherapy.
The implications of malignant transformation in subtotally excised
complex DNTs and the intriguing issue of the contribution of radiation/chemotherapy
are discussed. |
| MELANOTIC DIFFERENTIATION |
|
|
Melanotic differentiation in dysembryoplastic neuroepithelial tumor.
Elizabeth J, Bhaskara RM, Radhakrishnan VV, Radhakrishnan K, Thomas
SV.
Department of Pathology, Sree Chitra Tirunal Institute for Medical
Sciences and Technology, Thiruvananthapuram, Kerala, India.
|
Clin Neuropathol 2000 Jan-Feb;19(1):38-40 Abstract quote
Dysembryoplastic neuroepithelial tumor (DNT) is an uncommon intracranial
tumor which is usually encountered in patients with medically intractable
complex partial seizures of temporal lobe origin. Melanotic differentiation
in a DNT has not been reported previously.
Herewith we report a case of DNT with unique melanotic differentiation
in a 23-year-old female who presented with medically intractable epilepsy.
She underwent craniotomy and tumor decompression with a good outcome.
We present the histopathological features of DNT with melanotic differentiation
and discuss its prognostic significance.
|
| ROSETTE FORMING |
|
|
A rosette-forming glioneuronal tumor of the fourth ventricle: infratentorial
form of dysembryoplastic neuroepithelial tumor?
Komori T, Scheithauer BW, Hirose T.
Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester,
Minnesota 55905, USA.
|
Am J Surg Pathol 2002 May;26(5):582-91 Abstract quote
Eleven cases of a distinctive tumor of the posterior fossa are described.
The patients (age range 12-59 years) presented with headache and/or
ataxia.
Neuroimaging revealed a relatively discrete, focally enhancing mass(es)
primarily involving the aqueduct, fourth ventricle, and cerebellar vermis.
Hydrocephalus was present in seven cases, and two lesions were multicentric.
In two cases a significant increase in tumor size was documented. Gross
total or subtotal resections were achieved in 10 cases. One patient
underwent biopsy alone and another received postoperative irradiation.
Histologically, two components were identified in all cases. One consisted
of neurocytes forming neurocytic and/or perivascular pseudorosettes
in a fibrillary, partly microcystic matrix. The second, astrocytic component
resembled pilocytic astrocytoma in 10 cases and consisted of fibrillated
spindle cells with oval nuclei associated with occasional Rosenthal
fibers, granular bodies, glomeruloid capillaries, and microcalcifications.
Regionally, this component was more diffuse and patternless, consisting
of sheets of round to oval, oligodendrocyte-like cells. Rare ganglion
cells were seen in four cases. The rosettes were consistently synaptophysin
and MAP-2 immunoreactive, whereas the spindle cells were positive for
S-100 protein and glial fibrillary acidic protein. Overall, atypia was
minimal; no mitoses were found, and Ki67 labeling indices were low.
Ultrastructurally, the neurocytic cells featured processes containing
microtubules and occasional dense core granules. Mature synapses were
found in one of the four cases studied. Although the histologic features
of this unique tumor superficially resemble those of dysembryoplastic
neuroepithelial tumor, rosette formation by neuronal cells, the frequent
presence of a pilocytic astrocytoma component, and the growing nature
of the lesion argue against that diagnosis, as does occasional multifocality.
|
| SPECIAL STAINS/IMMUNOHISTOCHEMISTRY |
CHARACTERIZATION |
| GENERAL |
|
|
Dysembryoplastic neuroeptihelial tumor (DNT): an immunohistochemical
and ultrastructural study.
Hirose T, Scheithauer BW, Lopes MB, VandenBerg SR.
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester,
Minnesota 55905.
|
J Neuropathol Exp Neurol 1994 Mar;53(2):184-95 Abstract
quote
To assess the range of differentiation of the cells comprising dysembryoplastic
neuroepithelial tumor (DNT), particularly the oligodendrocyte-like cells
(OLC), 14 DNT were immunochemically studied with a spectrum of neuronal
and glial markers.
Eight tumors were also studied ultrastructurally. Neurofilament protein,
class III beta-tubulin, and synaptophysin preparations stained a few
OLC in two, six and one lesion, respectively. In addition, many OLC
within a single cortical nodule were reactive for class III beta-tubulin.
The vast majority of OLC were strongly S-100 protein positive. Glial
fibrillary acidic protein labeled a fair number of OLC in two cases
and one nodule consisted almost entirely of immunoreactive astrocytes.
Ultrastructurally, many OLC resembled oligodendrocytes in exhibiting
microtubules, prominent Golgi and short cell processes; pericellular
lamination of cell processes, a characteristic of oligodendroglia, was
noted in only one tumor. In two cases, OLC with astrocytic features
were seen to contain small numbers of intermediate filaments. In four
cases, a few OLC resembled immature neurons with scant dense-core granules
or synapses.
This study confirms the glioneuronal nature of DNT, a lesion composed
of heterogeneous cells, many resembling oligodendrocytes and a few showing
early astrocytic and neuronal differentiation. Although their relation
to OLC is unclear, the presence and peculiar distribution of mature
neurons is nonetheless an integral diagnostic feature of the lesion.
|
|
Dysembryoplastic neuroepithelial tumor: an immunohistochemical study
with myelin oligodendrocyte glycoprotein.
Gyure KA, Sandberg GD, Prayson RA, Morrison AL, Armstrong RC, Wong
K.
Armed Forces Institute of Pathology, Washington, DC 20306, USA.
|
Arch Pathol Lab Med 2000 Jan;124(1):123-6 Abstract quote
CONTEXT: The dysembryoplastic neuroepithelial tumor (DNT) is an uncommon
lesion characterized by a heterogeneous population of neurons, astrocytes,
and oligodendroglia-like cells (OLCs). The basic nature of the DNT and
its constituent cells, particularly the OLCs, remains unresolved; some
authors favor a neuronal origin, and others propose a glial or mixed
origin for these cells.
DESIGN: We examined 11 DNTs with antibodies to myelin oligodendrocyte
glycoprotein, a marker of mature oligodendrocytes.
RESULTS: All DNTs studied (7 from males, 4 from females; age range
of patients, 2-37 years) were composed of varying proportions of neurons,
astrocytes, and OLCs. Membrane or cytoplasmic immunoreactivity for myelin
oligodendrocyte glycoprotein was found in many OLCs in 9 of 11 cases.
The number of myelin oligodendrocyte glycoprotein-positive OLCs was
variable: >75% of the OLCs were positive in 5 cases, 25% to 75% of
the OLCs were positive in 2 cases, and <25% of the OLCs were positive
in 2 cases.
CONCLUSION: These findings suggest that many of the OLCs represent
mature oligodendrocytes and support the notion that DNTs are heterogenous
lesions composed of multiple, mature cell types.
|
| MIB1 |
|
|
Dysembryoplastic neuroepithelial tumor: a clinicopathologic and immunohistochemical
study of 11 tumors including MIB1 immunoreactivity.
Prayson RA, Morris HH, Estes ML, Comair YG.
Department of Anatomic Pathology, Cleveland Clinic Foundation, OH
44195, USA.
|
Clin Neuropathol 1996 Jan-Feb;15(1):47-53 Abstract quote
The dysembryoplastic neuroepithelial tumor (DNT) is a rare, recently
recognized neoplasm, characterized by a mixed glial-neuronal cell proliferation.
We studied 11 cases of DNT including 6 males and 5 females (age range
2.1-39.4 years, mean 13.8 years). All patients presented with chronic
epilepsy of 4.8 years mean duration. Nine tumors were located in the
temporal lobe and 2 in the frontal lobe. Four tumors were located on
the right side and 7 on the left. All tumors were characterized by a
predominant oligodendrocyte-like cell component with intermixed normal
appearing neurons and astrocytes. All were focally microcystic and 7
of 9 evaluable tumors were multinodular. Other observed histologic features
included a focal arcuate vascular pattern in 7 tumors, calcification
in 4 tumors, and a rare mitotic figure in 2 tumors. Necrosis and vascular
hyperplasia were not observed in any of the tumors. Cortical architectural
disorganization (cortical dysplasia) was observed in 9 of 10 evaluable
cases. MIB1 (a marker of cellular proliferation) immunostaining was
performed in all 11 tumors and MIB1 indices (number of positive tumor
cells/100 tumor cells counted) ranged from 0-0.6 (mean 0.2). Four patients
required at least 1 additional surgical procedure for tumor recurrence,
related to an incomplete initial excision 2.1-4.4 years after their
initial operation. All patients are seizure-free at their last follow-up.
DNTs are low grade neoplasms which typically present with chronic epilepsy,
are most frequently located in the temporal lobe, and occur most frequently
in pediatric patients.
Their appearance and association with cortical dysplasia suggest a
maldevelopmental origin. The generally slow growth and relatively benign
nature of DNT is reflected by their low MIB1 index.
|
| ELECTRON MICROSCOPY |
|
|
Dysembryoplastic neuroepithelial tumor (DNT): an ultrastructural study
of six cases.
Kordek R, Biernat W, Zakrzewski K, Polis L, Liberski PP.
Department of Molecular Biology, Polish Mother Memorial Hospital,
Lodz.
|
Folia Neuropathol 1999;37(3):167-70 Abstract quote
We report six cases od DNT with a detailed ultrastructural characteristics.
The patient age ranged from 7 to 16 years (mean 12), the location was
temporal in three cases and frontal, temporooccipital and parietooccipital
in each of one remaining cases.
The predominant clinical feature in each case was history of episodes
of intractable seizures. Histopathologically, the neoplasms were multinodular,
each nodule was well-circumscribed and was composed of glioneuronal
elements embedded in the variable amount of myxoid matrix. The oligodendroglial-like
cells (OLC) predominated in the nodules with some accompanying mature
neurons. The nodules were frequently surrounded by small calcifications
which could be found also within the tumors. OLCs were immunoreactive
for S-100 protein and neurons had the expression of synaptophysin and
neurofilament proteins.
Ultrastructurally, each tumor consisted of three major elements: neoplastic
cells (OLC), elongated processes forming neuropil-like structure and
expanded "mucoid" extracellular space: the latter gave an
impression of cellular elements floating within it. Neoplastic cells
had round, oval or elongated nuclei, no discernible nucleoli and a relatively
narrow rim of the cytoplasm. Some nuclei were irregular and invaginated
and pseudoinclusions were observed; a part of cytoplasm sequestered
within pseudoinclusions often appeared degenerated with large blabs
and electron-lucent vesicles, some of these contained in turn semicircular
profiles of unknown significance. The second element consisted of innumerable
cellular processes. Some of these were elongated and formed stacks connected
by symmetrical symmetric or asymmetric adhesive plaque junctions. The
others had shorter "neck" containing microtubules, these extended
into bullous extensions.
Dense-cored vesicles were occasionally observed, in both cytoplasm
of neoplastic cells and within processes. In one cell, cross-sectioned
annulate lamellae were found. In cytoplasm of a few cells, unusual inclusions
reminiscent ribosome-lamellae complexes were observed. These were cylindrical
resembling "laboratory tubes" with a cone-like endings. At
higher power, walls of the "tubes" resolved into layered structures
composed of several laminae; between laminae, ribosome-like structures
were visible.
|
| DIFFERENTIAL DIAGNOSIS |
KEY DIFFERENTIATING FEATURES |
| GENERAL |
|
|
Dysembryoplastic neuroepithelial tumor.
Prayson RA, Estes ML.
Department of Pathology, Cleveland Clinic Foundation, Ohio 44195-5138.
|
Am J Clin Pathol 1992 Mar;97(3):398-401 Abstract quote
Dysembryoplastic neuroepithelial tumor is a recently described but
rare tumor that occurs in children and characterized by long-standing,
intractable partial complex seizures.
Due to a paucity of literature on this condition and its heterogeneous
cellular composition, dysembryoplastic neuroepithelial tumors can present
difficulties in diagnosis. The authors describe two cases of dysembryoplastic
neuroepithelial tumor occurring in young patients (ages 8 and 19 years).
Both tumors were located in the temporal lobe. Temporal lobectomy with
excision of mesial structures resulted in resolution of the seizures.
Differential diagnosis includes oligodendrogliomas, mixed gliomas,
and gangliogliomas. Features of the dysembryoplastic neuroepithelial
tumor that are useful in making the distinction include a multinodular
and multicystic appearance, the presence of both neuronal and glial
(oligodendrocytic and astrocytic) components with little if any cytologic
atypia, the presence of accompanying cortical dysplasia, and the lack
of an arcuate vascular pattern. Because dysembryoplastic neuroepithelial
tumors are curable by excision, the recognition and correct diagnosis
of this tumor is important.
|
| OLIGODENDROGLIOMA |
|
|
Dysembryoplastic neuroepithelial tumor. A tumor with small neuronal
cells resembling oligodendroglioma.
Leung SY, Gwi E, Ng HK, Fung CF, Yam KY.
Department of Pathology, Queen Mary Hospital, University of Hong
Kong.
|
Am J Surg Pathol 1994 Jun;18(6):604-14 Abstract quote
Dysembryoplastic neuroepithelial tumor (DNT) is a clinicopathologically
unique group of tumors, mostly located in the temporal lobe, associated
with intractable complex partial seizure in young patients.
We report two unusual cases with multifocal involvement of diverse
sites in the central nervous system. Case 1 is that of a 50-year-old
man with 9-year history of grand mal seizures, who died of acute myocardial
infarction. Case 2 is that of a 10-year-old girl with intractable complex
partial seizures and behavioral disorder. Postmortem examination in
case 1 showed multifocal tumor in the left temporal lobe, third ventricle,
and basal ganglia. Magnetic resonance imaging in case 2 showed tumor
in the right temporal lobe, both thalami, right cerebellar hemisphere,
and pons. Histologically, both tumors were characterized by a multinodular
appearance with a predominant component of alveolar arrangement of oligodendroglial-like
cells around delicate capillaries, with mucoid matrix containing floating
ganglion cells. There were also astrocytic nodules resembling pilocytic
astrocytoma in case 1, and a gangliocytoma-like area merging with surrounding
cortical dysplasia in case 2.
Ultrastructural examination showed ganglionic differentiation in the
oligodendroglial-like cells in case 2. They possessed dense core neurosecretory
granules and many slender neuritic processes with microtubules arranged
in parallel and terminating in synaptic junctions. The periventricularly
located tumor with nodular extension to the periphery suggests an origin
from subependymal germinal matrix with nests of primitive neuroblasts
arrested in their embryonal migration. DNTs are related to ganglioglioma
based on their common location and clinical behavior and on the presence
of both ganglionic and astrocytic cells. They are also related to pilocytic
astrocytoma by morphological and behavioral similarity. Together with
cerebral neuroblastoma and central neurocytoma, they form a spectrum
of tumors harboring small neuronal cells. The differentiation of DNT
from oligodendroglioma is important so as to avoid unnecessarily aggressive
therapy.
|
| PROGNOSIS AND TREATMENT |
CHARACTERIZATION |
| Prognostic Factors |
|
|
Malignant transformation of a dysembryoplastic neuroepithelial tumor.
Case report.
Hammond RR, Duggal N, Woulfe JM, Girvin JP.
Department of Pathology, London Health Sciences Centre and University
of Western Ontario, Canada.
|
J Neurosurg 2000 Apr;92(4):722-5 Abstract quote
A 29-year-old man presented in 1984 with a recent onset of partial
seizures marked by speech arrest. Electroencephalography identified
a left frontotemporal dysrhythmia. Computerized tomography (CT) scanning
revealed a superficial hypodense nonenhancing lesion in the midleft
frontal convexity, with some remodeling of the overlying skull. The
patient was transferred to the London Health Sciences Centre for subtotal
resection of what was diagnosed as a "fibrillary astrocytoma (microcystic)."
He received no chemotherapy or radiation therapy and remained well for
11 years. The patient presented again in late 1995 with progressive
seizure activity. Both CT and magnetic resonance imaging demonstrated
a recurrent enhancing partly cystic lesion. A Grade IV astrocytoma was
resected, and within the malignant tumor was a superficial area reminiscent
of a dysembryoplastic neuroepithelial tumor (DNT).
Data on the lesion that had been resected in 1984 were reviewed, and
in retrospect the lesion was identified as a DNT of the complex form.
It was bordered by cortical dysplasia and contained glial nodules, in
addition to the specific glioneuronal element. The glial nodules were
significant for moderate pleomorphism and rare mitotic figures. The
Ki67 labeling index averaged 0.3% in the glial nodules and up to 4%
focally. Cells were rarely Ki67 positive within the glioneuronal component.
This case is the first documented example of malignant transformation
of a DNT. It serves as a warning of the potential for malignant transformation
in this entity, which has been traditionally accepted as benign.
This warning may be especially warranted when confronted with complex
forms of DNT. The completeness of resection in the benign state is of
paramount importance.
|
| SURVIVAL |
Behaves in benign fashion
Seven patients underwent gross total resection and two underwent subtotal
resection. No patients received adjuvant chemotherapy or radiotherapy.
On follow-up (n = 6; median, 14 months), all tumors had either not
recurred or were radiologically stable.
|
| TREATMENT |
|
|
Dysembryoplastic neuroepithelial tumor: a surgically curable tumor of
young patients with intractable partial seizures. Report of thirty-nine
cases.
Daumas-Duport C, Scheithauer BW, Chodkiewicz JP, Laws ER Jr, Vedrenne
C.
Department of Pathology, Hopital Sainte Anne, Paris, France.
|
Neurosurgery 1988 Nov;23(5):545-56 Abstract quote
This report concerns the clinicopathological features of 39 cases of
a morphologically unique and surgically curable group of neuroepithelial
tumors associated with medically intractable partial complex seizures.
All were supratentorial and characterized by intracortical location,
multinodular architecture, and heterogeneity in cellular composition.
The constituent cells included astrocytes, oligodendrocytes, and neurons.
Because neuronal atypia was often inapparent, the tumors superficially
resembled mixed oligoastrocytomas. The term "dysembryoplastic neuroepithelial
tumor" (DNT) is proposed for these distinctive lesions, the clinicopathological
features of which suggest a dysembryoplastic origin.
With the exception of the occurrence of headaches in 2 patients, partial
complex seizures were the exclusive symptom. Age at onset of symptoms
ranged from 1 to 19 years (mean 9 years). In addition to the chronic
nature of the seizures (range, 2 to 18 years; mean, 9 years), one-third
of the patients showed radiological features, such as focal cranial
deformity, indicating that the tumors had an early onset and were of
long standing. In most cases, computed tomography showed a "pseudocystic,"
well-demarcated, low density appearance associated in some cases with
focal contrast enhancement (18%) or calcific hyperdensity (23%). The
tumor involved the temporal lobe in 24 patients (62%), the frontal lobe
in 12 (31%), and the parietal and/or occipital lobe in 3 cases. Although
tumor removal was considered incomplete or subtotal in 17 patients (44%),
long term follow-up (range, 1 to 18 years; mean, 9 years) showed neither
clinical nor radiological evidence of recurrence in any patient. Comparison
of the survival data of the 13 subjects who had undergone postoperative
radiotherapy with 26 who had not indicated that radiation therapy was
of no obvious benefit.
he identification of DNT has therapeutic and prognostic implications
because aggressive therapy can be avoided, thus sparing these young
patients the deleterious long term effects of radio- or chemotherapy.
|
