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Background

Blastomycosis may be a benign and self-limiting infection or a chronic granulomatous and suppurative mycosis in which the primary infection is initiated in the lungs with frequent, subsequent dissemination to other body sites, especially the skin and bone. The disease is most prevalent in males 40-60 years of age and in children. Blastomycosis may coexist with bronchogenic carcinoma, histoplasmosis, severe pulmonary disease, or tuberculosis.

OUTLINE

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

EPIDEMIOLOGY CHARACTERIZATION
SYNONYMS Chicago disease, Gilchrist's disease, North American Blastomycosis
AGE RANGE-MEDIAN 40-60 years
SEX (M:F)
Males
GEOGRAPHY
 
AFRICA  


Blastomycosis in Africa: clinical features, diagnosis, and treatment.

Baily GG, Robertson VJ, Neill P, Garrido P, Levy LF.

Department of Medicine, University of Zimbabwe, Harare.

Rev Infect Dis 1991 Sep-Oct;13(5):1005-8 Abstract quote

Four cases of blastomycosis seen in two acute care hospitals in Harare, Zimbabwe, are described. All patients had symptoms of at least 2 months' duration before presentation, and all had radiographic evidence of pulmonary consolidation. Three patients had confirmed bone involvement, and two had chronic discharging sinuses.

The features of blastomycosis in Africa are reviewed, and problems of diagnosis and treatment are discussed. It is concluded that blastomycosis in Africa may often be misdiagnosed as tuberculosis or pyogenic infection in the absence of adequate facilities for mycologic investigation.

MISSISSIPPI RIVER BASIN
Endemic area

 

DISEASE ASSOCIATIONS CHARACTERIZATION
ACUTE RESPIRATORY DISTRESS SYNDROME  


Acute respiratory distress syndrome and blastomycosis: presentation of nine cases and review of the literature.

Lemos LB, Baliga M, Guo M.

Department of Pathology, Cytology Service, University of Mississippi Medical Center, Jackson, MS, USA.

Ann Diagn Pathol 2001 Feb;5(1):1-9 Abstract quote

Mississippi has the highest prevalence of blastomycosis in the country. In 20 years and 5 months there were 123 patients treated for blastomycosis at the University of Mississippi Medical Center.

Among these, 107 patients had lung involvement and nine patients (8.4%) developed acute respiratory distress syndrome. Seven of the nine patients (78%) died of respiratory failure. In six patients, the lungs were the only organs involved. The three other patients had involvement of other organs as well. Average survival after the onset of acute respiratory distress syndrome was 6.9 days (range, 2 to 17 days). Acute respiratory distress syndrome can be triggered by pulmonary infections caused by bacterial diseases and other fungi. Massive proliferation of yeasts in the pulmonary parenchyma is the typical finding of patients with blastomycosis and acute respiratory distress syndrome.

Underlying diseases that lead to immunodepression were present in only one patient and probable partial immunodepression was present in two other patients. Data from 19 other cases reported in the literature are discussed.

AIDS  


Blastomycosis in patients with the acquired immunodeficiency syndrome.

Pappas PG, Pottage JC, Powderly WG, Fraser VJ, Stratton CW, McKenzie S, Tapper ML, Chmel H, Bonebrake FC, Blum R, et al.

University of Alabama, School of Medicine, Birmingham.

Ann Intern Med 1992 May 15;116(10):847-53 Abstract quote

OBJECTIVE: To describe the clinical, demographic, radiographic, diagnostic, and therapeutic aspects of blastomycosis in patients with the acquired immunodeficiency syndrome (AIDS).

DESIGN: A retrospective survey.

SETTING: Ten university medical centers and community hospitals, six in geographic areas endemic for Blastomyces dermatitidis, and four outside the endemic area.

PATIENTS: We identified 15 patients with blastomycosis and positive serologic test results for human immunodeficiency virus (HIV).

MEASUREMENTS: A diagnosis of blastomycosis was based on a positive culture (14 patients) or typical histopathologic features (one patient) for B. dermatitidis in clinical specimens.

RESULTS: Twelve of 15 patients had a previous or concomitant AIDS-defining illness at the time of diagnosis of blastomycosis, and only one patient had a CD4 lymphocyte count of greater than 200 cells/mm3. Two patterns of disease emerged: localized pulmonary involvement (seven patients), and disseminated or extrapulmonary blastomycosis (eight patients). Central nervous system involvement was common (40%). Six patients died within 21 days of presentation with blastomycosis, including four patients with disseminated and two with fulminant pulmonary disease. Among the nine patients who survived longer than 1 month, all received amphotericin B as initial antifungal therapy, and most received subsequent therapy with ketoconazole. Only two of these nine patients died with evidence of progressive blastomycosis.

CONCLUSIONS: Blastomycosis is a late and frequently fatal infectious complication in a few patients with AIDS. In these patients, overwhelming disseminated disease including involvement of the central nervous system is common, and it is associated with a high early mortality. Initial therapy with amphotericin B is appropriate in patients with AIDS and presumptive blastomycosis.

PREGNANCY  


Blastomycosis and pregnancy.

Lemos LB, Soofi M, Amir E.

Department of Pathology, University of Mississippi Medical Center, Jackson, MS; and the Department of Pathology, University of Texas at Houston.

Ann Diagn Pathol 2002 Aug;6(4):211-5 Abstract quote

Blastomycosis is an exceedingly uncommon complication of pregnancy, rarely encountered by the practicing obstetrician.

However, recognizing its presence during pregnancy and expeditiously initiating appropriate therapy is of critical importance to the mother and fetus. Mississippi has the highest prevalence of blastomycosis in North America. Nevertheless, there have been only three pregnancies complicated by this fungal disease at the University of Mississippi Medical Center (Jackson, MS) during two decades. During the same time frame there were another 120 blastomycotic patients treated at the University of Mississippi Medical Center. As a condition of partial immunodepression, a nonobligatory opportunistic fungal disease like blastomycosis can complicate pregnancy.

From data on our three patients and 16 other published cases, it seems that fetal risk exceeds maternal risk. There were a total of 20 babies born from mothers with blastomycosis. Only two babies (10%) had transplacental infection and both succumbed to blastomycosis. None of the 18 affected mothers for whom data was available died of the disease. Furthermore, there was never progression in the mothers, with 14 complete cures and considerable postpartum regressions of lesions in the other four women. Even the three women who received no treatment had either noticeable improvement or total regression of the disease after delivery. One of the two stillborns with blastomycosis was born to an untreated mother.

 

PATHOGENESIS CHARACTERIZATION
Blastomyces dermatitidis

Thick-walled, globose yeast that measures 8-15 um in diameter

Each blastoconidium is attached to the parent cell by a broad base

 

LABORATORY/RADIOLOGIC/OTHER TESTS CHARACTERIZATION
RADIOLOGY  


Pulmonary blastomycosis: radiologic manifestations.

Halvorsen RA, Duncan JD, Merten DF, Gallis HA, Putman CE.

Radiology 1984 Jan;150(1):1-5 Abstract quote

Blastomycosis, an airborne fungal disease with the lung the portal of entry, is endemic to the central and south central areas of the United States.

The disease occurs in patients who range from asymptomatic to those with symptoms of acute pneumonia. Retrospective review of 27 cases from our institution revealed four well-defined radiographic patterns including air-space disease, nodular masses, interstitial disease, and cavitation. Some patients with air-space disease have symptoms of an acute pneumonia; more commonly they have no pulmonary symptoms. Air-space disease was the most frequent radiographic pattern in chronic blastomycosis with proved nonpulmonary disease; therefore, it cannot be regarded as indicative of early or acute blastomycosis. There was no relationship between the radiographic pattern and distribution, pulmonary symptomatology, or clinical stage of the disease.

Our material does not support the previously suggested association of lower lobe air-space disease with early disease and upper lobe involvement with the chronic and often disseminated form. A more precise understanding of the variety of radiographic patterns and the spectrum of clinical presentations will facilitate diagnosis of pulmonary blastomycosis.

LABORATORY  
GENERAL  


Pulmonary blastomycosis: an appraisal of diagnostic techniques.

Martynowicz MA, Prakash UB.

Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Mayo Medical School and Mayo Medical Center, Rochester, MN 55905-0001, USA.

 

Chest 2002 Mar;121(3):768-73 Abstract quote

OBJECTIVES: Pulmonary blastomycosis often mimics bacterial pneumonia or bronchogenic carcinoma, which may result in delayed therapy or the performance of unnecessary diagnostic procedures. We have reviewed the utilization of diagnostic techniques in the workup of patients with pulmonary blastomycosis, defined their diagnostic yields, and proposed an optimal diagnostic approach for the patient in whom pulmonary blastomycosis is considered.

DESIGN: Retrospective chart review of all patients with the diagnosis of blastomycosis at a major academic medical center.

RESULTS: Of the 119 patients with blastomycosis, 56 (47%) had pulmonary involvement. A total of 92 specimens were obtained by noninvasive means (sputa, 72 specimens; tracheal secretions, 5 specimens; and gastric washings, 15 specimens) in 35 patients. KOH smears were prepared from 22 of those specimens (24%). The diagnostic yield from these culture specimens obtained by noninvasive means was 86% per patient, and 75% per single sample. The diagnostic yields from KOH smears were 46% and 36%, respectively. Flexible bronchoscopy was performed in 24 patients and yielded a diagnosis in 22 (92%). Cultures of bronchial secretions (19 patients) and BAL fluid (6 patients) were positive in 100% and 67% of patients, respectively. The corresponding yields of KOH preparations were 17% (1 of 6 preparations) and 50% (3 of 6 preparations), respectively. Pathology specimens including those from bronchoscopic lung biopsies (nine patients), bronchial brushings (two patients), and bronchoscopic needle aspiration (one patient) were positive in 22%, 50%, and 0% of cases, respectively. Cytology was usually performed to exclude malignancy and was positive for Blastomyces dermatitidis in five patients (sputum, three patients; bronchial washings, two patients). Thoracotomy was performed in 11 cases, and in all patients the procedure yielded a diagnosis. Serology results were available in 25 patients. Immunodiffusion was positive in 10 patients (40%), and complement fixation in 4 patients (16%).

CONCLUSIONS: In patients with pulmonary blastomycosis, the positive yield from respiratory specimen cultures is high, but the confirmation of a diagnosis may take up to 5 weeks. Wet smears and cytology examinations of respiratory specimens provide quicker diagnoses but are underutilized. Their routine use is recommended in endemic areas. Commonly used serologic assays are insensitive and are not useful for diagnostic screening.

Culture

Sabouraud glucose agar, brain heart infusion agar, yeast-extract-phosphate agar, and a medium with cycloheximide, and then incubate at 30C

Grows best on the yeast extract agar or agar containing yeast extract such as Mould Inhibitory Agar (IMA)

Mould form to yeast form conversion is necessary to ensure that the fungus suspected to be B. dermatitidis is not a similar fungus-accomplished by inoculating Kelley's agar or blood agar supplemented with glutamine and then incubating the inoculated tubes at 37C

Exoantigen technique and a DNA culture confirmation kit
 
SEROLOGY  


Significance of false-positive serologic tests for histoplasmosis and blastomycosis in an endemic area.

Jordan MM, Chawla J, Owens MW, George RB.

Department of Medicine, Louisiana State University School of Medicine, Shreveport 71130.

Am Rev Respir Dis 1990 Jun;141(6):1487-90 Abstract quote

False-positive serologic tests for histoplasmosis (H) and blastomycosis (B) are common in populations from endemic areas. In order to determine the significance of false-positive test results, we reviewed the final diagnoses of all patients whose sera were submitted to our laboratory for radioimmunoassay (RIA) and immunodiffusion (ID) during a 3-yr period.

Of the 263 patients whose sera were examined, 29 (11%) had H or B; 41 (17.5%) of the remaining 234 patients had false-positive test results. Of these 41 patients, 31 were positive for H alone, and 10 had antibodies to both H and B. All three patients with false-positive ID tests for histoplasmosis also had positive titers (greater than or equal to 1:16) on RIA. No patient had a false-positive ID result for blastomycosis. The percentage of patients in each of five major diagnostic categories with and without false-positive serologic tests was similar (p greater than 0.05). The majority of patients had pulmonary infections, almost half of which were granulomatous infections other than H or B; this reflects the clinical indications for requesting fungal serologic tests.

A positive fungal serology is not useful in suggesting the presence of a pulmonary disease other than H or B in patients from an endemic area suspected of having a pulmonary mycosis.

 

GROSS APPEARANCE/CLINICAL VARIANTS CHARACTERIZATION
General  


Blastomycosis: organ involvement and etiologic diagnosis. A review of 123 patients from Mississippi.

Lemos LB, Guo M, Baliga M.

Cytopathology Service, Pathology Department, University of Mississippi Medical Center, Jackson, MS, USA.

Ann Diagn Pathol 2000 Dec;4(6):391-406 Abstract quote

Blastomycosis can only be diagnosed through the identification of the yeasts of Blastomyces dermatitidis in body fluids, tissues, or cultured material.

The charts from 123 patients treated for blastomycosis at the University of Mississippi Medical Center from January 1980 through May 2000 were reviewed to determine the role of wet preparation, cytology, histology, and culture in diagnosing this fungal disease. Cytology uncovered the etiologic agent in 56.1% of all cases and in 71.8% of pulmonary cases. Cytology also was the first method to disclose the fungus in 57.7% of pulmonary cases. Sputum was the cytology specimen examined in 51% of the patients. In 69 patients with lung involvement, pulmonary cytology was positive in 97% of cases. Wet preparation was the second method to most commonly uncover the fungus in 37.4% of all cases. Histology was the third method with 32.5% of positive cases. Cultures were positive in 64.2% of all cases but they were the first to detect the fungus in only 3.2% of all patients. There was pulmonary involvement in 87% of patients, cutaneous involvement in 20%, osseous involvement in 15%, and central nervous involvement in 3%. In the medical literature the relative proportion of pulmonary versus disseminated disease clearly increased in series reported after 1959.

Proportionally to the pattern of patients admitted to the University of Mississippi Medical Center, there is a clear predominance of black males among patients with blastomycosis followed by black females. White females constitute the sex/ethnic group least affected by this fungal disease.


Blastomycosis: The great pretender can also be an opportunist. Initial clinical diagnosis and underlying diseases in 123 patients.

Lemos LB, Baliga M, Guo M.

Department of Pathology, University of Texas, Houston; and the Department of Pathology, University of Mississippi, Jackson.

Ann Diagn Pathol 2002 Jun;6(3):194-203 Abstract quote

Clinically, blastomycosis can be difficult to recognize even in the endemic areas where clinicians are aware of this problem. In only 18% of 123 patients from the University of Mississippi Medical Center (Jackson, MS) blastomycosis was correctly suspected at the initial patient evaluation.

Pneumonia sensu latu (40%), malignant tumors (16%), and tuberculosis (14%) were the most common misdiagnoses. The false first impression frequently resulted in unnecessary surgeries or treatment delays, with patients receiving inefficient antibiotic therapy for months. The presence of cutaneous involvement by the disease makes its' recognition easier for the clinician, raising the percentage of correct initial diagnosis to 64%. To evaluate the association with immunodepression, the presence of other diseases was also searched among the 123 patients. An immunodepressive condition preceded the fungal disease in 25% of patients. Another associated disease commonly found in blastomycotic patients was diabetes mellitus (22%).

Blastomycosis is correctly suspected at the first clinical evaluation in only a small percentage of patients; pneumonia, cancer, and tuberculosis are the most common clinical considerations. Cutaneous involvement leads the clinician to the correct diagnosis in the majority of cases. One fourth of the patients with blastomycosis had underlying immunodepressive conditions, and underlying diabetes mellitus is present in 22% of patients.

VARIANTS  
BONE  


Delayed diagnosis of osseous blastomycosis in two patients following environmental exposure in nonendemic areas.

Veligandla SR, Hinrichs SH, Rupp ME, Lien EA, Neff JR, Iwen PC.

Department of Internal Medicine, University of Nebraska Medical Center, Omaha 68198-6495, USA

Am J Clin Pathol 2002 Oct;118(4):536-41 Abstract quote

Blastomycosis generally results from inhalation of Blastomyces dermatitidis conidia following exposure to contaminated soil in an endemic area. Primary infections commonly involve the lungs, although secondary dissemination to other body sites may occur.

We describe 2 cases of osseous blastomycosis in people living outside the endemic areas. Both patients reported exposure to soilfollowing injury to the knee from occupational activities. Mold isolated from each case was identified as B dermatitidis by micromorphologic characteristics including yeast conversion testing and by a positive AccuProbe Blastomyces dermatitidis test (GenProbe, San Diego, CA). Retrospective review of histologic slides, initially reported as negative, identified rare poorly staining, broad-based budding yeast forms in each case. Both patients were treated successfully with itraconazole with no evidence of recurrent infection after 1 year.

These cases illustrate the importance of considering blastomycosis in the differential diagnosis of bony lesions, even though the patient may live outside an endemic area for B dermatitidis.

CNS  


Cerebral blastomycosis. A report of 2 cases.

Cooper K, Lalloo UG, Naran HK.

Department of Anatomical Pathology, University of Natal, Durban.

S Afr Med J 1988 Nov 19;74(10):521-4 Abstract quote

Following recent documentation of blastomycosis in the RSA, a report of a further 2 cases in Natal is presented. The unusual feature of both cases was the presence of central nervous system involvement.

In the first patient intracerebral involvement occurred after apparent good response to ketoconazole when he defaulted from therapy after 3 months. The second patient presented with cerebral involvement and died soon after admission to hospital.

DISSEMINATED  

Disseminated blastomycosis.

Assaly RA, Hammersley JR, Olson DE, Farrouk A, Zaher A, Amurao GV, Shelley WB, Shelley ED, Amurao CV.

Department of Medicine, Divisions of Pulmonary/Critical Care and Dermatology, and Department of Pathology, Medical College of Ohio.

J Am Acad Dermatol 2003 Jan;48(1):123-7 Abstract quote

A 26-year-old veiled Saudi-Arabian woman presented with hemoptysis, and multiple nodules and abscesses. A skin biopsy specimen revealed yeast forms consistent with Blastomyces dermatitidis.

Fungal cultures from bronchoscopy and skin specimens also grew B dermatitidis. She was treated with oral itraconazole (200 mg twice a day). Both lung and skin lesions showed improvement within 6 weeks.

LARYNGEAL  


Laryngeal blastomycosis: a commonly missed diagnosis. Report of two cases and review of the literature.

Hanson JM, Spector G, El-Mofty SK.

Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.

Ann Otol Rhinol Laryngol 2000 Mar;109(3):281-6 Abstract quote

Blastomycosis is a relatively uncommon fungal disease that most commonly affects the lungs. Other organs may be involved, usually secondary to dissemination of the organism. Laryngeal blastomycosis may occur in isolation from active pulmonary disease. The signs, symptoms, clinical features, and pathological findings of laryngeal blastomycosis mimic those of squamous cell carcinoma. Misdiagnosis may result in inappropriate treatment with potential morbidity. Proper understanding of the clinical presentation and familiarity with the histopathologic features of this disease are therefore imperative. In this paper, we report 2 cases of laryngeal blastomycosis, 1 of which was misdiagnosed as squamous cell carcinoma, clinically and microscopically, with consequent radiotherapy and laryngectomy. In the other case, a clinical diagnosis of glottic squamous cell carcinoma was rendered. However, blastomycosis was identified in a biopsy specimen. We also review cases of isolated laryngeal blastomycosis that have been reported in the English-language literature during the last 80 years. A number of those cases were misdiagnosed clinically and microscopically as squamous cell carcinoma.

LUNG  


Epidemiological and clinical features of pulmonary blastomycosis.

Davies SF, Sarosi GA.

University of Minnesota Medical School, Hennepin County Medical Center, Minneapolis 55415, USA.

Semin Respir Infect 1997 Sep;12(3):206-18 Abstract quote

The epidemiological and clinical aspects of Blastomycosis are reviewed. The central United States is the most heavily endemic area in the world, although the extent of the endemic zone has been mapped only by individual case finding, rather than by large skin test surveys (as was done for histoplasmosis).

The difficulties in developing a sensitive and specific skin test antigen are reviewed, and the sequence of antigens from Blastomycin to antigen A to the ASWS (alkali and water soluble) antigen to the WI (Wisconsin) antigen are discussed. The absence of good immunological markers of remote subclinical disease means that the size of the iceberg of subclinical cases relative to clinically apparent and diagnosed pulmonary and extrapulmonary cases remains uncertain. Clinical presentations of blastomycosis range from (1) asymptomatic, currently discovered only in outbreak situation, (2) flulike illness of brief duration resembling other upper respiratory infections, (3) illness resembling bacterial pneumonia with acute onset, high fever, lobar infiltrates, and productive cough, (4) subacute or chronic respiratory illness with symptom complex resembling tuberculosis or lung cancer and radiographic presentation of fibronodular infiltrates or mass-like lesions, and (5) fulminant infectious adult respiratory distress syndrome (ARDS) with high fever, diffuse infiltrates, and progressive respiratory failure. Radiographic presentations are highly variable and even more confusing because of lack of standard terminology to describe these abnormalities.

Examples of some of the radiographic presentations of blastomycosis are shown. Available information concerning computed tomographic studies is also reviewed. Special mention is made of blastomycosis in AIDS, which is uncommon but tends to be fulminant, systemic, and rapidly progressive. An overview of current diagnostic strategies and treatment options is also presented.

PERITONEAL  


Peritoneal blastomycosis.

Perez-Lasala G, Nolan RL, Chapman SW, Achord JL.

Division of Infectious Diseases, University of Mississippi Medical Center, Jackson.

Am J Gastroenterol 1991 Mar;86(3):357-9 Abstract quote

Blastomycosis is a systemic fungal infection caused by Blastomyces dermatitidis. Involvement of the peritoneum is unusual, with only two previously reported cases that occurred in association with disseminated disease. A single case of histopathologically proven blastomycosis involving the peritoneum is presented, as well as a short overview of previously published cases on gastrointestinal and peritoneal blastomycosis. The case is unique in that chronic peritonitis was the only manifestation of disease. The diagnosis was made by laparoscopy.

SKIN  
Primary Cutaneous infection
Rare
May occur from traumatic implantation
Secondary cutaneous infection

Hematogenous spread from primary pulmonary infection

Annular, verrucous, or ulcerated plaques or nodules surrounded by a pustular margin

Central healing with atrophic scarring

 

HISTOLOGICAL TYPES CHARACTERIZATION
General

Acute suppurative and granulomatous inflammation

Fungi are usually demonstratable at the edge of the abscess with yeast cells are globose to ovoid in shape and approximately 8-15 um in diameter

Single blastoconidium is attached by a broad base to the parent cell

In most instances, predominantly single cells without attached blastoconidia are seen

The cell wall of the yeast is thick and appears doubly refractile

LUNGS Widespread granulomatous inflammation with small areas of abscess formation


Giant forms of Blastomyces dermatitidis in the pulmonary lesions of blastomycosis. Potential confusion with Coccidioides immitis.

Watts JC, Chandler FW, Mihalov ML, Kammeyer PL, Armin AR.

Department of Anatomic Pathology, William Beaumont Hospital, Royal Oak, Michigan 48072.

Am J Clin Pathol 1990 Apr;93(4):575-8 Abstract quote

Typical yeast-phase cells of Blastomyces dermatitidis have a characteristic appearance in tissue sections. Fungal morphologic variation occurs infrequently in the lesions of blastomycosis, yet it can complicate the differential diagnosis, particularly if fresh tissue is not available for microbiologic culture.

The authors report a case of pulmonary blastomycosis, confirmed by culture and direct immunofluorescence, in which some of the yeast-like cells were abnormally large. These giant yeast-like cells exceeded the size range accepted for the tissue forms of B. dermatitidis; therefore, coccidioidomycosis was considered initially in the differential diagnosis. Otherwise characteristic morphologic features of these cells, in particular multinucleation and the production of broad-based blastoconidia, helped resolve the differential diagnosis.

The diagnosis can be confirmed by direct immunofluorescence or microbiologic culture.

SKIN Pseudoepitheliomatous hyperplasia with focal microabscesses in the papillary dermis


Cutaneous lesions showing giant yeast forms of Blastomyces dermatitidis.

Walker K, Skelton H, Smith K.

Departments of Dermatology and Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA.

J Cutan Pathol 2002 Nov;29(10):616-8 Abstract quote

Background: The yeast forms of Blastomyces dermatitidis usually range from 8 to 15-20 micro m in diameter. Larger yeast forms have previously been reported only twice in immunosuppressed patients. In both patients these large forms were seen within the lung.

Case report: We present a 14-year-old cardiac transplant patient, who presented 36 days following his transplantation with acute respiratory distress followed a few days later by erythematous cutaneous papules. Results: Biopsy of a skin lesion showed yeast forms, some greater than 40 micro m in diameter, within and surrounding dermal vessels. Cultures later grew Blastomyces dermatitidis.

Conclusion: To our knowledge this is the first reported case of giant forms of Blastomyces dermatitidis within the skin. With increased iatrogenic immunosuppression, we may expect to see more diverse morphologic forms with deep fungal infections.

SKIN-SWEET'S SYNDROME-LIKE CHANGES  


Sweet's Syndrome-Like Blastomycosis.

Wilkerson A, King R, Googe PB, Page RN, Fulk CS.


Am J Dermatopathol 2003 Apr;25(2):152-4 Abstract quote

Cutaneous North American blastomycosis is characterized clinically by verrucous nodules and histologically by pseudoepitheliomatous hyperplasia, intraepidermal neutrophilic microabscesses, and a dermal mixed inflammatory cell infiltrate containing giant cells.

We describe a patient who presented clinically with erythematous nodules and plaques on the lower extremities characterized histologically by a diffuse neutrophilic infiltrate, with lack of epidermal hyperplasia. The lesions were clinically and histologically reminiscent of Sweets syndrome.

On close microscopic inspection scattered histiocytes and multinucleated giant cells were present in the dermis, and fungal stains demonstrated budding yeast forms consistent with Blastomyces sp.

   

 

SPECIAL STAINS/IMMUNOPEROXIDASE/OTHER CHARACTERIZATION
Special stains PAS and GMS stains positive

 

PROGNOSIS AND TREATMENT CHARACTERIZATION
Treatment

Amphotericin B is the drug of choice, and at least 1.5 gm must be given to avoid relapse

Hydroxystilbamidine has been used with success in treating the cutaneous form of the disease

Itraconazole and voriconazole should be considered

Am J Clin Pathol 1983;79:253-255
Clin Infect Dis 1996;22:102S-111S


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