Cryptococcus, Pathological observations of five autopsy cases and one biopsy case

Pathologic, anatomical, and histological findings of 5 autopsy cases and one biopsy case of cryptococcosis have been described. Macroscopically the foci of the lung are grayish white or yellowish white in color and range in size from the small acinous-nodular ones to the larger lobular-nodular ones. In the brain the meninx appears gelatinous and edematous showing many small spots with indistinct boundary and with grayish white color. Lymph nodes infected with fungi are swollen in various degrees. Histologically the foci are mainly consisted of granulomatous inflammation containing giant cells. Besides, there are small degenerative foci having no inflammatory response and the lesions of marked fibrosis; the former will be newly formed foci and the latter the old ones. The size of C. neoformans found in tissue ranges from 3 to 30 μ, and the majority of fungi possess thick gelatinous capsule, but some of them in granulative lesions often possess no capsule. From the staining properties the capsule of C. neoformans is believed to be a kind of acid mucopolysaccharide. As for the staining method including general fungi, GOMORI's methenamine silver method is best, especially for the detailed examination of fungus structures, and for the differential diagnosis mucicarmine stain is the most suitable one. In tracing the distribution of the foci in the various organs, it seems that the first attack of this fungus occurs in the lung. The authors have called general attention, through their own experiences, to the fact that the small granulomatous foci caused by Cryptococcus infection, especially in the lung, may often escape the detection at autopsy.