1993 Volume 34 Issue 2 Pages 155-163
This report describes pathological aspects of deep-seated trichosporonosis in cases reported in the literature (including our own) and in experimental animals, as follows: 1) Morphology of Trichosporon in the tissue sections was, although similar to Candida, characterized by the presence of both pseudohyphae and true hyphae of varying widths, and by various-shaped spores including arthroconidia. Immunostaining was useful in making a diagnosis of trichosporonosis in cases of unsuccessful culture of the causative organism. 2) In the literature up to 1991, 85 cases of deep-seated trichosporonosis had been reported. Sixty-seven cases were sepsis or disseminated infections and 55 had a hematological disorder, particularly leukemia, as an underlying disease. Many cases with unfavorable prognosis had necrotic or no cellular reactions in fungal lesions, while the improved cases showed, at least in part, suppurative and/or granulomatous inflammation, indicating that a patient's prognosis depends on the degree of impairment of the host defense mechanism. 3) Experimental trichosporonosis in mice confirmed the importance of host defense; intravenous inoculation of Trichosporon beigelii into leukopenic mice treated with anti-neoplastic drugs caused a generalized spread of fungal lesions without cellular reactions, while formation of suppurative granuloma with quick removal of the fungi was observed only in lungs in untreated control animals.
