Saprophytic mycosis appearing as a necrotic bronchial tumor and masking lung cancer

: We describe four cases of saprophytic mycosis superficially covering lung cancer to form a bronchial necrotic tumor. Although the first biopsy in each case disclosed mycosis with necrosis, repeated transbronchial biopsy revealed malignant cells. In two of the four cases, we started treatments for lung cancer based on the clinical diagnosis preceding histological diagnosis. Although no treatment to eliminate fungi was performed, all cases showed an uneventful clinical course. It is important not to misdiagnose cancer as a fungal disease on the basis only of a transbronchial biopsy, and to bear in mind this type of saprophytic mycosis.