Identification of coccidioidomycosis of the lung by fine needle aspiration biopsy

A solitary coin lesion in the lung is a frequent presentation of coccidioidomycosis; these lesions may be radiologically indistinguishable from cancer. In a series of 112 fine needle aspiration (FNA) biopsies performed in the San Joaquin Valley on solitary pulmonary nodules, 8 cases were identified as coccidioidomycosis by the presence of spherules in the aspirated material. The immature sporangia ranged in size from 4 micron to 40 micron. The smaller spherules did not show endospores and could have been confused with red blood cells. A methenamine silver or periodic acid-Schiff stain was helpful in identifying the spherules following decolorization of Papanicolaou-stained material; this was especially important when the background material was bloody. Older nonviable spherules showed a folded collapsed cell membrane, which may be associated with long-standing cavitary disease. A complement fixation titer was frequently not elevated. This study demonstrates the utility of FNA biopsy in the identification of cocci granulomas in the lung.