Paracoccidioidomycosis With Oropharyngeal Manifestation and a Nodulariform Pulmonary Pattern Mimicking Malignancy: A Case Report

Paracoccidioidomycosis is an endemic systemic fungal infection in Latin America, caused by fungi of the genus Paracoccidioides. The disease can affect multiple organs, but the pulmonary form is the most common, while isolated oropharyngeal involvement is a rare presentation. This type of involvement may be confused with malignant neoplasms, often leading to diagnostic delays. We report the case of a 55-year-old immunocompromised man, with a history of heavy smoking and chronic skin lesions, who developed persistent odynophagia and a unilateral plaque in the left oropharynx for more than one year. Due to persistence of the lesion and suspicion of malignancy, he underwent biopsy of the affected area. Histopathology revealed the presence of oropharyngeal blastomycosis, suggesting the need for further investigation. Chest computed tomography showed extensive bilateral ground-glass opacities with a nodulariform pattern, predominantly in the upper segments of the lower lobes, consistent with pulmonary fungal involvement. Laboratory tests showed significant eosinophilia (9.3%) and hemoglobin of 13.6 g/dL, which also supported the diagnostic hypothesis. After diagnostic confirmation, treatment was started with liposomal amphotericin B for 14 days, followed by itraconazole 200 mg/day for six months. During clinical follow-up, significant improvement was observed, with resolution of oropharyngeal lesions and reduction of pulmonary changes on follow-up imaging. This case highlights the importance of considering systemic mycosis in the differential diagnosis of patients with persistent oropharyngeal complaints and atypical lung lesions, especially in individuals with risk factors such as smoking history and exposure to rural environments. It also underscores the relevance of early diagnosis, which can avoid unnecessary invasive procedures, such as biopsies or aggressive treatments, and improve patient prognosis. Active surveillance in endemic areas and early recognition are essential for effective management of this fungal infection, which, when treated appropriately, has a good chance of complete remission.