Paracoccidioidomycosis simulating brain tumor

BACKGROUND: Paracoccidioidomycosis (PCM) is a systemic granulomatous disease caused by Paracoccidioides brasiliensis. Involvement of the central nervous system (CNS) occurs in about 10% of cases. CASE DESCRIPTION: A 57-year-old white man presented with the complaint of headache and an episode of focal seizure 1 month earlier. Magnetic resonance imaging (MRI) revealed a ring-enhancing lesion in the right parietal lobe with peri-lesional vasogenic edema suggestive of a primary neoplasm. The patient underwent craniotomy and the intraoperative finding was a yellowish, hard lesion with thick content and yellow inside. Anatomo-pathological findings were pathognomonic of PCM: large, thick-walled, spherical yeast cells with multiple peripheral buds. The patient tested negative for human immunodeficiency virus (HIV). Encephalitis and meningitis were ruled out by cerebrospinal fluid analysis. Culture confirmed the diagnosis of PCM and the patient was treated with amphotericin B. The patient responded well to treatment with resolution of the headache and clinical improvement, despite a bitemporal hemianopia. He was clinically stable and then discharged in good general condition. CONCLUSIONS: Radiographic findings of PCM with CNS involvement may suggest neoplasia, making diagnosis difficult. In endemic areas, the diagnosis of PCM should be promptly considered when a ring-enhancing mass associated with peri-lesional edema is observed on MRI.