Paracoccidioidomycosis is an endemic systemic mycosis in Latin America caused by Paracoccidioides spp., infecting humans mainly through inhalation of spores. The chronic form is more common in adult men and may progress with severe pulmonary, mucocutaneous, and lymphatic manifestations. Clinical recognition and histologic diagnosis are essential to avoid therapeutic delays and prevent complications. A 60-year-old male, previously healthy, presented with an ulcerated lesion, painful to touch, located in the edentulous region of tooth 48, “where the tooth fell out by itself one year ago.” Oral examination showed an ulcerated area with irregular, erythematous borders and exposed bone, without signs of suppuration, accompanied by local discomfort. He denied comorbidities or associated systemic conditions. Initial diagnostic hypotheses included squamous cell carcinoma, oral tuberculosis, and deep mycoses. An incisional biopsy was performed, showing mucosa lined by parakeratinized stratified squamous epithelium with acanthosis and exocytosis, associated with an intense chronic granulomatous inflammatory infiltrate rich in lymphocytes, epithelioid macrophages, and multinucleated giant cells. Rounded, thick-walled, birefringent structures compatible with Paracoccidioides fungi were observed, confirmed by special stains (periodic acid–Schiff and Grocott). Areas of chronic sialadenitis were also seen in adjacent salivary glands, along with muscle bundles and hemorrhagic foci in the deep connective tissue. The definitive diagnosis was oral paracoccidioidomycosis, chronic form, presenting as a localized lesion in the oral cavity. The patient was referred for specialized follow-up and initiation of specific antifungal therapy on an outpatient basis, with a plan for prolonged treatment. Exclusively oral presentation of paracoccidioidomycosis without clinical or laboratory evidence of systemic involvement is an atypical expression of the chronic form of the disease, broadening recognition of its phenotypic diversity and emphasizing the importance of clinico-pathologic correlation in endemic settings. Although oral mucosal involvement is common in disseminated disease, localized and isolated presentations in the oral cavity are uncommon and may mimic neoplastic lesions, delaying definitive diagnosis.
Maison et al. (2026) studied this question.