Coccidioides immitis. A rare cause of pulmonary mycetoma.

Coccidioides immitis occurring as a fungus ball within a chronic pulmonary cavity has previously been reported twice and must be rare. We report a mycetoma composed of both spherule and mycelial forms of Coccidioides immitis, proved by culture and histologic sections. Fungus ball due to Coccidioides immitis is a logical progression from mycelia seen in the cavity wall in the active pulmonary coccidioidal lung cavity.