MEDICAL MYCOLOGY

Dr Tadayo Hashimoto M.D.
Professor
Department of Microbiology & Immunology

20. A healthy middle-aged construction worker who engaged in a demolition task 10 days ago complains of respiratory symptoms similar to those of pneumonia. No causative agents are successfully isolated from his sputa. The patient does not respond to any antibacterial antibiotics and dies before a definitive diagnosis was established. Microscopic examination of specimens taken from granulomatous and suppurative lesions of the lung obtained during necropsy reveals the presence of large budding yeast cells. The bud is attached to the parent cell by a broad base. Based on this data, you diagnose the disease of this patient as:

histoplasmosis
coccidioidomycosis
cryptococcosis
blastomycosis
sporotrichosis

(D) The key diagnostic finding is the morphology of the yeast isolated from granulomatous and suppurative lesions of the lung. Blastomyces dermatitidis, which causes blastomycosis, grows in yeast form in infected tissues. The bud of growing yeast is attached to the parent cell by a broad base. Although the fungi that cause all other diseases listed in the question grow in yeast form in infected tissues, most buds are attached to the parent cell by a narrow base. (Joklik et al, pp. 1103-1108; Ryan et al, pp. 606-607)

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