Pulmonary infection with capsule-deficient cryptococcus neoformans.

A case of bilateral lobar pneumonia due to Crytococcus neoformans is presented. The capsule-deficient fungal organisms within tissue were suggestive of Histoplasma capsulatum. Cultures grew Cryptococcus neoformans and there was cryptococcal antigen in the serum. Pulmonary cryptococcosis and the occurrence of unencapsulated cryptococci are reviewed. The important role both culture and the latex agglutination test for cryptococcal antigen play in the differential diagnosis of systemic fungal infections with over-lapping histopathology are discussed.