A case of oral paracoccidioidomycosis difficult to differentiate from oral carcinoma

Paracoccidioidomycosis (PCM) is a fungal disease endemic to Latin America. PCM is a systemic granulomatous disease that primarily affects the lungs and causes ulcerative and granulomatous lesions in the oral cavity. Diagnosis is often difficult owing to the rarity of the disease outside of Latin America. Therefore, we present a rare case of oral PCM that is difficult to differentiate from oral carcinoma. The patient was a 76-year-old Japanese man who had previously worked in Bolivia decades ago. A 14 × 18 mm intractable ulcer under a fixed partial prosthesis in the mandibular posterior region caused severe contact pain. Oral carcinoma was initially suspected, and a detailed examination was performed. However, the ulcer was diagnosed as PCM on biopsy. The oral lesion improved after an antifungal drug was administered. At approximately seven months follow-up, the patient remained recurrence-free.