Home Diseases and Health Information  

Home Home Translating Report News Physicians Diseases Body Sites Diseases and Health Information Search


There are many clinical variants of this disease all united by the characteristic histologic find of a cornoid lamella. Although rare, the development of a squamous cell carcinoma may occur. This development underscores the fact that the cornoid lamella represents an abnormal clone with abnormal DNA ploidy and mutation.


Disease Associations  
Laboratory/Radiologic/Other Diagnostic Testing  
Gross Appearance and Clinical Variants  
Histopathological Features and Variants  
Special Stains/
Electron Microscopy
Differential Diagnosis  
Commonly Used Terms  
Internet Links  


AGE Usually middle aged to elderly



Hereditary non-polyposis colorectal cancer associated with disseminated superficial porokeratosis. Microsatellite instability in skin tumours.

Takata M, Shirasaki F, Nakatani T, Takehara K.

Department of Dermatology, Kanazawa University School of Medicine, 13-1 Takara-machi, Kanazawa 920-8641, Japan.

Br J Dermatol 2000 Oct;143(4):851-5 Abstract quote

A 73-year-old man presented with typical lesions of disseminated superficial porokeratosis (DSP) and multiple seborrhoeic keratoses on his face, trunk and extremities, and later developed a keratoacanthoma on his lip. He belonged to a cancer-prone pedigree susceptible to colonic, uterine and other internal cancers, and had a personal history of early gastric cancer and advanced adenocarcinoma of the descending colon without adenomatous polyps at age 59 years.

Polymerase chain reaction amplification of skin samples for seven separate microsatellite polymorphisms revealed microsatellite instability (MSI) at multiple loci in five of six seborrhoeic keratoses and the keratoacanthoma, strongly suggesting underlying defects in DNA mismatch repair. Although no germline mutations in two mismatch repair genes hMSH2 and hMLH1 were found, our patient was recognized as having hereditary non-polyposis colorectal cancer (HNPCC) based on the family history and the findings of the microsatellite analysis of skin tumours. This confirmed the usefulness of detection of MSI in prevalent and readily accessible skin lesions, including non-sebaceous non-dysplastic tumours such as seborrhoeic keratosis in the screening of HNPCC families.

Although DSP may also be inherited as an autosomal dominant condition, this particular skin disease appeared to be sporadic in our patient and, to our knowledge, no association of DSP or other forms of porokeratosis with HNPCC has previously been reported. In contrast to the seborrhoeic keratoses and keratoacanthoma, no MSI was observed in two samples from DSP lesional epidermis examined.


Synchronous development of disseminated superficial porokeratosis and hepatitis C virus-related hepatocellular carcinoma.

Kono T, Kobayashi H, Ishii M, Nishiguchi S, Taniguchi S.

Department of Dermatology, Osaka City University Medical School, 1-4-3, Asahimachi, Abeno-ku, Osaka 545-8585, Japan.

J Am Acad Dermatol 2000 Nov;43(5 Pt 2):966-8 Abstract quote

Immunosuppression and transplantation have been reported to induce porokeratosis (PK), especially its variant, disseminated superficial PK (DSP). On the other hand, there is ample evidence of a relationship between hepatitis C virus (HCV) infection, liver cirrhosis (LC), and hepatocellular carcinoma (HCC).

We report 3 cases of DSP in which the outbreak of DSP was suspected to have occurred during the development of HCC in patients with HCV-positive LC. The patients had undergone ultrasonographic study regularly, and no signs of malignancy had been found before the development of DSP. Their outbreaks of DSP were very acute, and the period between the development of DSP and diagnosis of HCC ranged from 2 to 6 months.

The association of HCV-related HCC and DSP has never been previously reported. HCV-induced immunomodulation or its effect on the p53 system may be the basis for this type of association. It is necessary to consider development of HCC whenever DSP is found in HCV-positive patients. DSP may be a new paraneoplastic dermadrome.


Postirradiation multiple minute digitate porokeratosis.

Pujol RM, Perez-Losada E, Matias-Guiu X, Fuentes J, Alonso MC, Alomar A, Craven-Bartle J.

Department of Dermatology, Hospital del Mar, IMAS, Barcelona, Spain.

J Cutan Med Surg 2001 Mar-Apr;5(2):126-30 Abstract quote

BACKGROUND: Development of multiple minute digitate hyperkeratoses (MMDH) after irradiation has been reported previously. The keratotic lesions in these cases were confined within the irradiation field, and histopathological examination disclosed a focal column of parakeratosis (cornoid lamella) arising from an epidermis devoid of granular layer.

OBJECTIVE: We describe a 78-year-old woman who developed multiple, discrete, tiny, filiform, keratotic papules on the anterior aspect of the right chest wall, 13 months after postmastectomy cobalt irradiation therapy for mammary infiltrating ductal carcinoma.

CONCLUSION: Postirradiation MMDH represents a peculiar radiation-induced disorder that we believe should be distinguished from other cases of MMDH and included within the spectrum of porokeratosis.

Porokeratosis of Mibelli induced by topical corticosteroid.

Department of Dermatology, Ege University Medical Faculty, Bornova-Izmir, Turkey.


J Cutan Pathol. 2006 Jul;33(7):516-8 Abstract quote

BACKGROUND: Prorokeratosis of Mibelli is a chronic disorder characterised by slightly atrophic plaques surrounded by keratotic border.

METHODS AND RESULTS: A 45-year-old with clobetazole propionate ointment for psoriasis over 15 years developed characteristic lesions of porokeratosis Mibelli on the elbows. Histopathological examination revealed the cornoid lamellae located on the edges of the specimen and psoriasiform acanthosis and a spongiotic pustule formation in the center of the specimen; thus, it was suggested as 'psoriasis encircled by porokeratosis'.

CONCLUSIONS: Development of porokeratosis may be explained by the local immunosuppressive effect of the prolonged application of the topical steroid.

Porokeratosis in immunosuppressed and nonimmunosuppressed patients.

Raychaudhuri SP, Smoller BR.

Department of Dermatology and Pathology, Stanford University School of Medicine, California.

Int J Dermatol 1992 Nov;31(11):781-2 Abstract quote

Porokeratosis is an uncommon, inherited, autosomally dominant disorder. In the last decade association of porokeratosis and immunosuppression has been observed. In this study we carried out a comparative study between immunosuppressed and nonimmunosuppressed porokeratosis cases.

We found that 9 out of 20 cases of porokeratosis were associated with organ transplantation/immunosuppression. Clinicopathologic study revealed that the pattern of disease is alike both in immunosuppressed and nonimmunosuppressed patients.

Our observations indicate that immune modulation could be a factor in the genesis of porokeratosis.

Sudden onset of disseminated porokeratosis of Mibelli in a renal transplant patient.

Knoell KA, Patterson JW, Wilson BB.

Department of Dermatology at the University of Virginia, Charlottesville, USA.

J Am Acad Dermatol 1999 Nov;41(5 Pt 2):830-2 Abstract quote

Porokeratosis is a disorder of epidermal keratinization of uncertain cause. Five clinical variants of porokeratosis have been described. These include porokeratosis of Mibelli, punctate porokeratosis, linear porokeratosis, porokeratosis palmaris plantaris et disseminata, and disseminated superficial porokeratosis. Disseminated superficial porokeratosis and single plaque porokeratosis of Mibelli have each been documented to occur in association with immunosuppression.

To our knowledge, only 5 cases of disseminated porokeratosis of Mibelli in transplant recipients have been reported.

We present a patient who developed explosive onset of disseminated porokeratosis of Mibelli shortly after renal transplantation. It is important to differentiate this unusual variety of porokeratosis from other cutaneous manifestations in transplant patients so that appropriate therapy can be instituted.


Two closely linked variations in actin cytoskeleton pathway in a Chinese pedigree with disseminated superficial actinic porokeratosis.

Zhang ZH, Huang W, Niu ZM, Liu WD, Xiang LH, Yuan WT, Zhao JJ, Gu CY, Chai B, Jiang FX, Zhang J, Xu SJ, Zheng ZZ.

Department of Dermatology, Hua Shan Hospital, Shanghai Medical College, Fu Dan University, Shanghai, PR China.

J Am Acad Dermatol. 2005 Jun;52(6):972-6. Abstract quote  

BACKGROUND: Disseminated superficial actinic porokeratosis (DSAP) is an uncommon autosomal dominant chronic keratinization disorder, characterized by multiple superficial keratotic lesions surrounded by a slightly raised keratotic border. Recently, SSH1 was identified as the DSAP candidate gene.

OBJECTIVE: Our purpose was to determine the locus of DSAP and identify the candidate gene(s) of the disease.

METHODS: Genome-wide scanning and linkage analysis were performed in a 6-generation Chinese family with DSAP. The coding exons and promoter region of the candidate genes were screened for the nucleotide variations.

RESULTS: A missense mutation (p.Ser63Asn) in SSH1 and a variation (dbSNP3759383: G>A) in the promoter region of ARPC3 were closely linked with DSAP in the pedigree.

CONCLUSION: Both SSH1 and ARPC3 are involved in the actin cytoskeleton pathway and interacted with adherent junctions in the epidermal cells. We suggested that cytoskeleton disorganization in epidermal cells was likely associated with the pathogenesis of DSAP.
Gene expression profiling of porokeratosis demonstrates similarities with psoriasis.

Hivnor C, Williams N, Singh F, Vanvoorhees A, Dzubow L, Baldwin D, Seykora J.

Department of Dermatology, University of Pennsylvania Medical School, Philadelphia, PA, USA.

J Cutan Pathol. 2004 Nov;31(10):657-64. Abstract quote  

Background: Porokeratosis (PK) is a clinically heterogeneous entity associated with sharply demarcated, annular, or serpiginous lesions with a hyperkeratotic ridge. This disorder is associated with aberrant keratinocyte differentiation that histologically manifests as a stack of parakeratin termed the cornoid lamella; this structure represents the peripheral hyperkeratotic ridge of clinical lesions. Histologically, the keratinocytes forming the cornoid lamella demonstrate an altered differentiation program. However, the molecular basis of PK remains incompletely understood.

Methods: As a first step in characterizing PK at the molecular level, gene expression profiling was performed on a cornoid lamella isolated from a large, Mibelli-type porokeratotic lesion. As a control, gene expression profiling of peripheral uninvolved epidermis was also performed. The gene expression profile of cornoid lamellar keratinocytes was compared with similar profiles obtained from a psoriatic plaque and cutaneous squamous cell carcinoma.

Results: Our study demonstrates a striking similarity between the gene expression profiles of PK and psoriasis. In addition, novel markers of the porokeratotic keratinocytes were identified, including keratin 16, S-100 A8 and A9, and connexin 26.

Conclusions: This study supports the hypothesis that PK is a disorder of hyperproliferative keratinocytes exhibiting similarity at the molecular level to psoriasis.

Chromosomal instability and cellular hypersensitivity to X-radiation of cultured fibroblasts derived from porokeratosis patients' skin.

Watanabe R, Ishibashi Y, Otsuka F.

Department of Dermatology, Faculty of Medicine, University of Tokyo, Japan.

Mutat Res 1990 Jun;230(2):273-8 Abstract quote

Porokeratosis is a rare genetic skin disorder known to be associated with a propensity to develop skin cancer.

To further elucidate the previously reported cytogenetic and cellular abnormalities, we studied karyotypic changes and the sensitivity to X-ray irradiation of cultured fibroblasts derived from skin lesions and normal-appearing skin of 3 patients with porokeratosis. Cultured fibroblasts from normal-appearing skin of 9 controls were similarly examined. Porokeratosis subjects had a greater number of cells with chromosomal abnormalities than controls. Two porokeratosis strains which were derived from the normal-appearing skin of a patient had a noticeable clone of abnormal cells. Porokeratosis fibroblasts were hypersensitive to the lethal effects of X-radiation. This hypersensitivity was common to both the lesion-derived strains and the ones derived from normal-appearing skin. The 2 strains with clonal abnormal cells were also similarly hypersensitive to X-radiation.

These results suggest that chromosomal instability is strongly related to porokeratosis and that X-ray hypersensitivity is an inherent abnormality in cultured fibroblasts of porokeratosis patients

Identification of a locus for disseminated superficial actinic porokeratosis at chromosome 12q23.2-24.1.

Xia JH, Yang YF, Deng H, Tang BS, Tang DS, He YG, Xia K, Chen SX, Li YX, Pan Q, Long ZG, Dai HP, Liao XD, Xiao JF, Liu ZR, Lu CY, Yu KP, Deng HX.

National Laboratory of Medical Genetics of China, Department of Neurology, Xiangya Hospital, Hunan Medical University, Changsha, China.

J Invest Dermatol 2000 Jun;114(6):1071-4 Abstract quote

Disseminated superficial actinic porokeratosis is an autosomal dominant cutaneous disorder characterized by many uniformly small, minimal, annular, anhidrotic, and keratotic lesions. The genetic basis for this disease is unknown.

Using a genomewide search in a large Chinese family, we identified a locus at chromosome 12q23.2-24. 1 responsible for disseminated superficial actinic porokeratosis. The fine mapping study indicates that the disseminated superficial actinic porokeratosis gene is located within a 9.6 cM region between markers D12S1727 and D12S1605, with a maximum two-point LOD score of 20.53 (theta = 0.00) at D12S78.

This is the first locus identified for a genetic disease where the major phenotype is porokeratosis. The study provides a map location for isolation of a gene causing disseminated superficial actinic porokeratosis.


Overexpression of p53 tumor suppressor protein in porokeratosis.

Magee JW, McCalmont TH, LeBoit PE.

Department of Pathology, University of California, San Francisco.

Arch Dermatol 1994 Feb;130(2):187-90 Abstract quote

BACKGROUND: p53 is a tumor suppressor nucleoprotein. Mutations of the p53 gene have been found in a variety of malignant neoplasms. Wild-type p53 has a short half-life, possibly only 20 to 30 minutes, and is not present in the nucleus at levels that are detectable with routine immunohistochemical techniques. Mutant p53 has a longer half-life, and is readily detectable with immunoperoxidase staining.

RESULTS: We studied 17 specimens from patients with either porokeratosis of Mibelli or actinic porokeratosis, using immunoperoxidase staining with an antibody directed against the p53. There was staining of lesional keratinocyte nuclei in 16 of 17 specimens, limited in most cases to the zone between cornoid lamellae. Staining for proliferating cell nuclear antigen was increased above background levels in only six of 13 specimens.

CONCLUSIONS: The finding of p53 immunoperoxidase staining in porokeratosis suggests genetic mutation, as occurs in other cutaneous keratinocytic neoplasms, and the lack of corresponding proliferating cell nuclear antigen expression in many specimens indicates that p53 overexpression is not simply a reflection of increased cellular proliferation.


p53 alterations in porokeratosis.

Arranz-Salas I, Sanz-Trelles A, Ojeda DB.

Department of Pathology, Hospital Carlos Haya, Malaga, Spain.


J Cutan Pathol. 2003 Aug;30(7):455-8. Abstract quote.

BACKGROUND: Porokeratosis (PK) is a group of cutaneous entities characterized by disordered epidermal keratinization and by a predisposition to develop malignant transformation. The molecular mechanism of this carcinogenesis remains unclear, but p53 has been proposed as a mediator of this process. p53 overexpression, detected by immunohistochemistry, has frequently been reported in PK, and p53 mutations are direct results of ultraviolet (UV) skin exposure and are directly involved in most common skin cancers.

METHODS: Eleven cases of Mibelli-type PK, one of them associated with a squamous cell carcinoma, were reviewed. Formalin-fixed, paraffin-embedded archival tissue from these cases was immunostained for p53 and used for DNA extraction for the analysis of p53 mutations by polymerase chain reaction and single-strand conformation polymorphism.

RESULTS: Increased p53 expression was confirmed in all cases. Most of them showed a discontinuous labeling, often stronger at the base of the cornoid lamella. No relation with sun exposure was observed. Finally, no p53 mutations were found at the gene levels more frequently damaged in human cancers called 'hot spots'.

CONCLUSIONS: p53 alterations can be involved in the pathogenesis of the PK and the carcinogenesis arising in some of the lesions. Since p53 gene inactivation in human cancer is related to mutation and/or loss, the absence of genetic damage could indicate that p53 alterations are only at the protein level, leading to an abnormal cell-cycle control. UV exposure does not seem to play a main role in the process.

p53, mdm-2, and p21 waf-1 in the porokeratoses.

Nelson C, Cowper S, Morgan M.

Department of Pathology, University of South Florida College of Medicine, Tampa, USA.

Am J Dermatopathol 1999 Oct;21(5):420-5 Abstract quote

The etiology of the porokeratoses is unknown. Overexpression of the p53 tumor suppressor protein and disregulated cell cycle control have been pathogenically implicated. The p53 tumor suppressor gene product is regulated by mdm2 and both gene products influence cell cycle progression through the cyclin-dependent kinase inhibitor p21.

Thirty-three cases of the various types of porokeratosis were immunohistochemically studied for p53, mdm2, and p21 proteins. Each of the cases showed increased p53 and decreased mdm2 and p21 expression within keratinocytes underlying cornoid lamella.

This study confirms the previous findings of increased p53 staining and expands the potential roles of mdm2 and p21 in the pathogenesis of the porokeratoses.




Porokeratosis as a premalignant condition of the skin. Cytologic demonstration of abnormal DNA ploidy in cells of the epidermis.

Otsuka F, Shima A, Ishibashi Y.

Department of Dermatology, Faculty of Medicine, University of Tokyo, Japan.

Cancer 1989 Mar 1;63(5):891-6 Abstract quote

Clinical evidence has accumulated of malignant epithelial tumors developing on the lesions of porokeratosis.

To determine the cytologic basis for the malignant change of porokeratosis, the nuclear DNA content of epidermal cells from porokeratotic lesions was measured using microfluorometry. A total of 42% of 33 porokeratotic skin lesions in eight of the 16 patients showed DNA polyploidization in the epidermis. Most of the porokeratotic skin lesions, with or without DNA polyploidization, increase cell proportions in the S and G2/M phase range. DNA indices of cells from these porokeratotic lesions distributed widely from the level of normal control epidermis to that of malignant epidermal conditions.

These findings suggest that porokeratosis is undergoing the neoplastic process, and is a precursor of malignant tumors.



Coexistence of disseminated superficial porokeratosis in childhood with congenital linear porokeratosis.

Suh DH, Lee HS, Kim SD, Cho KH, Kim KH, Park KC.

Department of Dermatology, Seoul National University College of Medicine, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea.

Pediatr Dermatol 2000 Nov-Dec;17(6):466-8 Abstract quote

Porokeratosis is a genodermatosis characterized by abnormal epidermal keratinization with the histologic finding of cornoid lamella. To date, five clinical variants have been identified. However, the coexistence of these variants in a single patient has been described only rarely.

We report a 5-year-old girl with the simultaneous occurrence of porokeratotic lesions in linear and disseminated patterns. Linear lesions were detected at birth and the disseminated lesions developed at the age of 3 years. Histologically the lesions had cornoid lamella, which is typical of this condition.

Disseminated superficial actinic porokeratosis (DSAP) Multiple annular keratotic lesions with thin hyperkeratotic border

Porokeratosis in the elderly: a new subtype of disseminated superficial actinic porokeratosis.

Patrizi A, D'Acunto C, Passarini B, Neri I.

Department of Clinical and Experimental Medicine, University of Bologna, Italy.

Acta Derm Venereol 2000 Jul-Aug;80(4):302-4 Abstract quote

In a review of all cases of porokeratosis histologically diagnosed in our Department during the period 1991-98 we found that 12 patients (22%) were in their seventh to ninth decade. In all 12 (2 males and 10 females) the age of onset of the disease varied between 58 and 89 years (mean age 68.6 years). The clinical picture was similar in all the patients, with the number of lesions varying from a few to 20-50 annular plaques 10-15 mm in diameter, localized mainly on the lower limbs.

We suggest that our patients had a very mild form of disseminated superficial actinic porokeratosis confined to the extremities with an unusually late onset. This peculiar variety of late-onset disseminated superficial actinic porokeratosis may represent a type of immunosuppression-induced porokeratosis where the pathologic clone for porokeratosis is present but remains latent until the amount of sun exposure, together with the physiological age-related lowering of immunocompetence, bring about its proliferation.

Type 2 segmental manifestation of disseminated superficial porokeratosis showing a systematized pattern of involvement and pronounced cancer proneness.

Murata Y, Kumano K, Takai T.

Department of Dermatology, Hyogo Medical Center for Adults, 13-70, Kitaojicho, Akashi, 673-8558, Japan.

Eur J Dermatol 2001 May-Jun;11(3):191-4 Abstract quote

Nine tumors of squamous cell carcinoma developed in a 61-year-old Japanese woman with linear porokeratosis. She had disseminated superficial porokeratosis, but a linear arrangement of pronounced lesions was found only on the left side of the body, and all of the tumors arose on the linear lesions on the left side of the body. Some of her family members had disseminated superficial porokeratosis.

This case may represent a type 2 segmental manifestation of disseminated superficial porokeratosis showing a systematized pattern of involvement and pronounced cancer proneness.

Porokeratosis of Mibelli Round oval plaques with an atrophic center and thin elevated rim
Porokeratosis plantaris discreta Painful plantar lesions
Punctate porokeratotic keratoderma  
Porokeratosis punctata palmaris et plantaris Asymptomatic pits or plugs on the hands and feet
Porokeratosis plantaris, palmaris et disseminata Annular and serpiginous lesions on the palms and soles with later involvement of other areas



Disseminated superficial actinic porokeratosis. A histological review of 61 cases with particular reference to lymphocytic inflammation.

Shumack S, Commens C, Kossard S.

Skin and Cancer Foundation, Darlinghurst, N.S.W., Australia.

Am J Dermatopathol 1991 Feb;13(1):26-31 Abstract quote

The pathology of 61 cases of disseminated superficial actinic porokeratosis was reviewed and the relative frequency of the histological features associated with the cornoid lamella and the pathology within and outside the porokeratotic rim were assessed.

Papillary dermal lymphocytic infiltrate (97%), spinous layer vacuolar changes (90%), dyskeratotic cells in the epidermis (77%), and liquefaction degeneration of the basal layer (67%) were frequently seen under the cornoid lamella. Papillary lymphocytic infiltration was seen more frequently inside the porokeratotic ring in comparison to the outer skin.

Lymphocyte marker studies in nine cases showed a predominance of activated T lymphocytes with positive LN3 and UCHL-1 staining.

Together with the finding of a lichenoid reaction pattern, these results lend support to the hypothesis that actinic porokeratosis represents a migrating clone of abnormal keratinocytes with an associated immunological host response.


Punched-out porokeratosis. A histological variant of disseminated superficial actinic porokeratosis.

Burge SM, Ryan TJ.

Am J Dermatopathol 1987 Jun;9(3):240-2 Abstract quote

This paper describes an unusual histological variant of disseminated superficial actinic porokeratosis in which there were areas of full-thickness coagulative epidermal necrosis. The diagnosis of porokeratosis was confirmed with a further biopsy, which demonstrated a coronoid lamella and some underlying basal cell liquefaction. The significance of the pathology is discussed.


The hyperkeratotic variant of disseminated superficial actinic porokeratosis (DSAP).

Jang KA, Choi JH, Sung KJ, Moon KC, Koh JK.

Department of Dermatology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.

Int J Dermatol 1999 Mar;38(3):204-6 Abstract quote

A 78-year-old South Korean man was referred to us from the Medical Intensive Care Unit (MICU) for an opinion.

He was comatose and was on ventilatory care due to aspiration pneumonia. Multiple tiny papules had developed 10 years previously and since then the number and size had been increasing gradually. He had been diabetic for the past 4 years, and had Parkinson's disease diagnosed 1 year previously. Laboratory examinations revealed an elevated level of white blood cells (WBCs) (25,000/microL) and decreased hemoglobin (8.8 g/dL). Other laboratory results were negative or within normal limits. Skin examination showed multiple, discrete, crust-like, brownish papules over the erythematous base on the face, upper extremities, and lower extremities.

With the clinical impressions of irritated verruca vulgaris, seborrheic keratosis, or cutaneous fungal infection, a skin biopsy was taken from a papule on the left shin, and histopathologic examination revealed several pronounced hyperkeratotic and parakeratotic columns, and characteristic cornoid lamellae in the stratum corneum. Beneath the cornoid lamellae, the granular layer was decreased. A number of round or oval, dyskeratotic, homogenized eosinophilic cells with pyknotic nuclei were scattered in the prickle cell layer below the cornoid lamellae. A mild lymphohistiocytic infiltrate was observed in the papillary dermis and around the blood vessels in the upper dermis. Also, actinic degeneration was present in the upper dermis.


*Department of Pathology and Immunology, Barnes-Jewish Hospital/Washington University School of Medicine †Cutaneous Pathology, WPC Laboratories, Inc, St Louis, MO.


Am J Surg Pathol. 2007 Dec;31(12):1897-1901. Abstract quote

Cornoid lamellation is a specific disorder of epidermal maturation manifested by a vertical "column" of parakeratosis and is the hallmark of porokeratosis. The cornoid lamella is characterized by a ridgelike parakeratosis.

We present 11 patients with solitary lesions of a distinct pattern of cornoid lamellation. The mean age at presentation clinically was 57 years; there were 9 men and 2 women. The duration of the lesions ranged from 3 months to 5 years (mean of 23 mo). All lesions were solitary, distributed mainly on the distal upper and lower limbs, and were clinically described as hyperkeratotic plaques or nodules; some were verrucous.

Histologic examination showed a well-defined lesion characterized by acanthosis and verrucous hyperplasia with prominent multiple and confluent cornoid lamellae. No additional lesions were identified in any patient, with a mean follow-up duration of 34 months. No personal or family history of porokeratosis was elicited and no immunosuppressive conditions were noted. These lesions with multiple and confluent cornoid lamellae represent benign acanthomas with features of porokeratosis.

As a solitary tumorlike lesion, it is akin to warty dyskeratoma and epidermolytic acanthoma, thus we have coined the term porokeratoma.

Porokeratosis plantaris discreta. A case showing transepidermal elimination.

Kang WH, Chun SI.

Department of Dermatology, Yonsei University Wonju College of Medicine, Korea.

Am J Dermatopathol 1988 Jun;10(3):229-33 Abstract quote

A 16-year old girl developed multiple, well-demarcated, extremely painful, hyperkeratotic nodules on her left sole. Histologic examination revealed a cornoid lamella and transepidermal elimination of blood vessels and collagen fibers which may be caused by the acceleration of keratinization. The pain and tenderness may have been partially related to epidermal disruption.



Porokeratoses: immunohistochemical, light and electron microscopic evaluation.

Jurecka W, Neumann RA, Knobler RM.

Department of Dermatology II, University of Vienna, Austria.

J Am Acad Dermatol 1991 Jan;24(1):96-101 Abstract quote

Punch biopsy specimens of 14 patients with porokeratosis of Mibelli (n = 1), disseminated superficial porokeratosis (n = 6), disseminated superficial actinic porokeratosis (n = 4), porokeratosis plantaris, palmaris et disseminata (n = 2), and punctate porokeratosis (n = 1) were obtained for light and electron microscopy for evaluation of possible differences between these clinical variants. Langerhans cells in close contact with early degenerating keratinocytes could be observed in the epidermis.

To study the cellular composition of the epidermal inflammatory infiltrate immunohistochemistry was performed. These studies demonstrated that the predominant cell type in these infiltrates are helper T cells, intermingled with Leu-6+ Langerhans cells.

Despite the clinical variation and possible different etiologic or triggering mechanisms, the immunohistochemical and morphologic changes in all types of porokeratosis are the same and seem to represent a uniform reaction pattern.


Morphogenesis of the cornoid lamella: histochemical, immunohistochemical, and ultrastructural study of porokeratosis.

Ito M, Fujiwara H, Maruyama T, Oguro K, Ishihara O, Sato Y.

Department of Dermatology, Niigata University School of Medicine, Japan.

J Cutan Pathol 1991 Aug;18(4):247-56 Abstract quote

To elucidate the morphogenesis of cornoid lamellae (CL) in porokeratosis, skin lesions of three cases of disseminated superficial actinic porokeratosis and a case of linear porokeratosis were examined.

By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, SH groups were present in the living layer of the epidermis beneath CL and irregularly disappeared at the bottom of CL, whereas SS linkages appeared in dyskeratotic cells in the living layer and in the irregularly shaped cell membranes of the horny cells. Epidermis beneath CL showed an increased and irregular involucrin expression. Ultrastructurally, the living keratinocytes contained many cytoplasmic vacuoles and had a smaller number of lamellar bodies than normal. Intercellular lamellar sheets were incompletely formed. The dyskeratotic cells and the lower horny cells contained many small vacuoles but formed a marginal band.

The horny cells of CL also formed a marginal band and, further, a keratin pattern. CL may be formed by hyperproliferative atypical kertatinocytes which keratinize rapidly and irregularly and show defective desquamation due to the paucity of intercellular lamellar sheets.


Circumscribed Palmar or Plantar Hypokeratosis: Two Cases of a Recently Described Entity of Unknown Origin.

Mensing CH, Schleusner VH, Sander CA, Mensing H.

From the *Department of Dermatology, Allgemeines Krankenhaus St. Georg, Hamburg, Germany; and daggerDermatologist in private practice, Hamburg, Germany.

Am J Dermatopathol. 2005 Jun;27(3):247-249. Abstract quote  

Circumscribed palmar or plantar hypokeratosis is a new entity recently described by Perez et al in 2002. It seems to be underdiagnosed or clinically it is often misdiagnosed as Bowen's disease or porokeratosis. Obviously the number of case reports of circumscribed palmar or plantar hypokeratosis has increased since the first publication by Perez et al.

The histopathological hallmarks of this condition are a stair-like configuration with an abrupt thinning of the stratum corneum from uninvolved to involved skin with a central hypokeratotic area. There are no atypical keratinocytes or cornoid lamellation.

We describe two new patients with circumscribed palmar hypokeratosis. In one case there were additional histopathological features including the loss of granular cell layer in the center of the lesion and an overlying compact thin parakeratotic layer.

Circumscribed palmar or plantar hypokeratosis: a distinctive epidermal malformation of the palms or soles.

Perez A, Rutten A, Gold R, Urbina F, Misad C, Izquierdo MJ, Requena C, Aliaga A, Kutzner H, Requena L.

Department of Dermatology, Hospital General Universitario, Valencia, Spain.

J Am Acad Dermatol 2002 Jul;47(1):21-7 Abstract quote

BACKGROUND: Epidermal malformations of the skin include a group of heterogeneous developmental defects that result from errors in morphogenesis of the epidermis during intrauterine life.

OBJECTIVE: The purpose of this study was to report the clinical and histopathologic features of a distinctive epidermal malformation involving the skin of the palms or soles.

METHODS: Ten patients were included in this study. All of them showed the same clinical features that consisted of a solitary circumscribed and circular area of erythematous depressed skin on the palm or on the sole. Diagnosis was confirmed by histopathologic study.

RESULTS: All patients were middle aged or elderly. Nine patients were women and one was a man. The lesions showed predilection for the skin of the thenar and hypothenar regions of the palm or the medial side of the sole. Histopathologic study demonstrated a depression of the epidermis, with a sharp stair between normal and involved skin. The epidermis covering the depression showed markedly thinner horny layer and a slightly diminished granular cell layer when compared with adjacent noninvolved skin. Keratinocytes of the squamous cell layer, granular cells, and corneocytes showed, otherwise, a normal appearance. Serial sections failed to demonstrate cornoid lamellation.

CONCLUSION: On the basis of the clinical and histopathologic findings in these 10 patients, we have named this malformation circumscribed palmar or plantar hypokeratosis. This lesion seems to be a distinctive entity that has not been previously described.

Lichenoid dermatitis  



Disseminated porokeratosis accompanying multicentric Bowen's disease. Characterization of porokeratotic lesions progressing to Bowen's disease.

Otsuka F, Huang J, Sawara K, Asahina A, Ishibashi Y.

Department of Dermatology, Tokyo University Hospital, Japan.

J Am Acad Dermatol 1990 Aug;23(2 Pt 2):355-9 Abstract quote

Multicentric Bowen's disease developed in a 73-year-old man in areas involved with disseminated porokeratosis. The porokeratotic lesions were brownish; some were small and solitary, and others were coalesced and of variable size. Some lesions were erythematous. The histologic findings of the small, solitary or brownish, coalesced lesions were those of porokeratosis without apparent dysplasia; however, the erythematous coalesced lesions revealed epidermal dysplasia.

Study revealed DNA ploidy abnormalities in the epidermal cells of these porokeratotic skin lesions. The skin lesions progressed in their degree of DNA ploidy abnormality from small solitary lesions to brownish coalesced ones and further to erythematous, coalesced ones.

These observations suggest the direct and sequential growth of potentially malignant neoplastic clones in the patient's porokeratotic skin lesions and explain the multicentric development of Bowen's disease.

Squamous cell carcinoma arising from lesions of porokeratosis palmaris et plantaris disseminata.

Seishima M, Izumi T, Oyama Z, Maeda M.

Department of Dermatology, Ogaki Municipal Hospital, Minaminokawa-cho, 4-86, Ogaki 503-8502, Japan.

Eur J Dermatol 2000 Aug;10(6):478-80 Abstract quote

We report a 63-year-old Japanese man with numerous hyperkeratotic papules of porokeratosis palmaris et plantaris disseminata (PPPD) who developed multiple squamous cell carcinomas on the lesional sites of the palms and soles.

The hyperkeratotic papules, which showed tightly packed columns of parakeratotic cells in the cornified layer (cornoid lamella), lost granular layer, and dyskeratotic keratinocytes in the epidermis below the cornoid lamella histologically, had been noticed on the palms and soles from the age of 28 and 43, respectively. He has no family history of such hyperkeratotic papules. Treatment with etretinate (10-50 mg/day) was given discontinuously, and the total dose of etretinate amounted to approximately 21 g over 14 years (average: 0.07 mg/kg/day). He noticed erosions on the hyperkeratotic papules on the left sole and palm more than 9 months after cessation of treatment with etretinate. Histological findings showed numerous atypical keratinocytes in the epidermis and upper dermis with mononuclear cell infiltration seen in the upper dermis. The diagnosis of squamous cell carcinoma arising from the lesions of porokeratosis palmaris et plantaris was made. Five erosions with histologically malignant changes were removed 1 cm from the margin of the erosions.

These findings suggest that etretinate may have an inhibitory action on malignant changes in PPPD.

Disseminated porokeratosis with fatal metastatic squamous cell carcinoma: an additional case of "Malignant Disseminated Porokeratosis".

Rongioletti F, Rebora A.

Department of Endocrinological and Metabolic Diseases, Section of Dermatology, University of Genoa, Genoa, Italy.

Am J Dermatopathol 2002 Apr;24(2):144-8 Abstract quote

We report on a patient with a disseminated form of porokeratosis in whom bowenoid lesions and squamous cell carcinoma developed in an apparent sequential progression. Local and disseminated metastases ensued, resulting in the death of the patient. Furthermore, we found an overexpression of the p53 protein in the keratinocytes beneath and adjacent to the cornoid lamella in the porokeratotic lesion and throughout the epidermis in a bowenoid lesion.

Although malignancy has been reported previously in various types of porokeratosis, the development of fatal metastatic squamous cell carcinoma in the setting of this disease is a rare event.

The histopathologic findings of this case document the association of porokeratotic lesions with bowenoid dysplasia and aggressive squamous cell carcinoma and confirm that a p53 functional aberration can be important in a malignant outcome such as this.


Treatment of porokeratosis of Mibelli with CO2 laser vaporization versus surgical excision with split-thickness skin graft. A comparison.

Rabbin PE, Baldwin HE.

Department of Dermatology, State University of New York-Health Science Center, Brooklyn 11203.

J Dermatol Surg Oncol 1993 Mar;19(3):199-202 Abstract quote

BACKGROUND. Porokeratosis of Mibelli has been treated with many topical surgical modalities in the past, including cold steel surgical excision and CO2 laser excision. We report a patient with an 8 x 10 cm2 plaque of porokeratosis on the dorsum of his hand, fingers, and web spaces.

OBJECTIVE. To compare the treatment results of CO2 laser vaporization versus cold steel surgical excision with split-thickness skin graft placement.

METHOD. The portions of the lesion overlying the metacarpophalangeal joints, fingers, and web spaces were treated with CO2 laser vaporization. The remainder of the lesion covering the dorsum of the hand was excised with cold steel, followed by placement of a split-thickness skin graft over that area.

RESULTS. The portion of the porokeratosis lesion treated with CO2 vaporization healed with results cosmetically and functionally superior to the grafted area.

CONCLUSION. Carbon dioxide laser vaporization, a more superficial treatment modality than CO2 laser excision, should be the preferred treatment modality for porokeratosis lesions.

Successful treatment of porokeratosis with 585 nm pulsed dye laser irradiation.

Alster TS, Nanni CA.

Washington Institute of Dermatologic Laser Surgery, Washington, DC, USA.

Cutis 1999 May;63(5):265-6 Abstract quote

Porokeratosis, a keratinization and fibroblast cutaneous disorder, is a progressive disease with limited treatment options.

We describe a case of linear porokeratosis that responded favorably to a series of 585 nm pulsed dye laser treatments. In addition to its vascular specificity, the pulsed dye laser presumably produces a direct effect on collagen, as well as an indirect effect on histamine and mast cells that could account for the clinical changes seen in our patient.

Macpherson and Pincus. Clinical Diagnosis and Management by Laboratory Methods. Twentyfirst Edition. WB Saunders. 2006.
Rosai J. Ackerman's Surgical Pathology. Ninth Edition. Mosby 2004.
Sternberg S. Diagnostic Surgical Pathology. Fourth Edition. Lipincott Williams and Wilkins 2004.
Robbins Pathologic Basis of Disease. Seventh Edition. WB Saunders 2005.
DeMay RM. The Art and Science of Cytopathology. Volume 1 and 2. ASCP Press. 1996.
Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
Fitzpatrick's Dermatology in General Medicine. 6th Edition. McGraw-Hill. 2003.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

Commonly Used Terms

Coronoid lamella -A parakeratotic column representing a clonal disorder of keratinocytes. A hallmark of porokeratosis although it can be seen in other diseases.

Basic Principles of Disease

Learn the basic disease classifications of cancers, infections, and inflammation

Commonly Used Terms
This is a glossary of terms often found in a pathology report.

Diagnostic Process
Learn how a pathologist makes a diagnosis using a microscope

Surgical Pathology Report
Examine an actual biopsy report to understand what each section means

Special Stains
Understand the tools the pathologist utilizes to aid in the diagnosis

How Accurate is My Report?
Pathologists actively oversee every area of the laboratory to ensure your report is accurate

Got Path?
Recent teaching cases and lectures presented in conferences

Internet Links

Pathologists Who Make A Difference
Search for a Physician Specialist
Clinical Photo
Clinical Photo
Clinical Photo

Microscopic Photo

Last Updated December 4, 2007

Send mail to The Doctor's Doctor with questions or comments about this web site.
Read the Medical Disclaimer.

Copyright © The Doctor's Doctor