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Fig. 6.47 A-C. Abdominal coccidioidomycosis. Although the liver, spleen, and kidneys can be affected in disseminated coccidioidomycosis, lymphadenopathy is also a frequent finding. A, B Distortion of the stomach and duodenum by enlarged lymph nodes, with localized adhesions and direct spread. C A different patient with lymphadenopathy and adhesions causing partial intestinal obstruction in the mid and lower abdomen.

Fig. 6.48 A, B. The histopathology of sporotrichosis. A Several well-circumscribed granulomas with diffuse infiltration of neutrophils around them and, on the left, a heavy mononuclear infiltration. H & E, x 160. B Although it is often difficult to demonstrate Sporothrix schenckii, the appearance is characteristic. There is a "narrow neck;" budding, and a surrounding layer of Splendore-Hoeppli material. Gomori methe namine-silver, x 1300. (A from Bittencourt and Londero 1995; B courtesy of Dr. D. H. Connor)



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Previously known as North American blastomycosis, because this is where it was first described and most cases occur, blastomycosis has now been reported throughout Africa, in the Middle East, and in some parts of Europe.


Gilchrist's disease: Chicago disease. Fr. Blastomycose. Ger: Blastomykose. Sp: Blastomicos Norte Americana.


Blastomycosis is an infection caused by the fungus Blastomyces dermatitidis.

Geographic Distribution

Blastomycosis is most commonly found in North America, from Canada through Mexico and parts of Central America. It is endemic in the Mississippi River Basin, around the Great Lakes and in the southeastern United States. It is now also recognized in many other parts of the world, particularly in Africa a (large number of cases are reported from Zimbabwe).

Epidemiology and Pathology

Only recently has B. dermatitidis been isolated from the soil of river banks. Man is infected by inhalation of mycelia or rarely through the skin. This fungus is an occupational hazard for microbiologists and pathologists. Dogs, cats, and cows are infected, but no man to man or animal to man transmission is known except from dog bites and possibly in one case in which a man with a urinary tract infection was probably the source of pelvic blastomycosis in his wife. Inhalation of the infectious conidia of the mycelial form results in alveolitis with exudation of fluid and inflammatory cells, which can be localized or diffuse. Initially, there is an inflammatory predominantly suppurative pyogranulomatous reaction, in which fungal cells are extracellular. Subsequently there may be an abscess and foci of necrosis. In the more chronic pattern the appearance varies with the age of the lesion and the immune status of the patient. In the lungs there may be compact granulomas or confluent, suppurative granulomas with central necrosis. Healing occurs with fibrosis and sometimes cavitation: calcification and caseation are uncommon. Blastomycosis eventually causes a chronic granulomatous inflammation, with hyalinization: fibrosing mediastinitis is a complication, but less often than in histoplasmosis capsulati.

Cutaneous blastomycosis causes a pseudoepitheliomatous hyperplasia with intraepidermal and dermal microabscesses, containing fungal colonies surrounded by epithelioid giant cells. There may be similar hyperplastic lesions in the larynx. When dissemination occurs, the skin, the mucosa of the respiratory tract, the genitourinary tract, bones, and the CNS may all be affected. Unlike in paracoccidioidomycosis, the gastrointestinal system is seldom involved. In patients with a poor immune status, the fungal cells may proliferate heavily and there is minimal inflammatory response.


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