Histopathological diagnosis of invasive pulmonary candidiasis mimicking bronchogenic carcinoma in an immunocompetent adult: a case report

Background. Invasive pulmonary candidiasis is an uncommon and frequently disputed diagnosis because Candida species commonly colonize the respiratory tract without causing tissue invasion. Definitive diagnosis, therefore, relies on histopathological demonstration of fungal invasion with concurrent inflammation. We report a case of invasive pulmonary candidiasis presenting as an endobronchial mass mimicking bronchogenic carcinoma in an adult male without known immunosuppression. Case presentation. A 49-year-old Ugandan male presented with a two-month history of dry cough, chest pain, progressive worsening dyspnea, intermittent fever, and non-bloody diarrhea. The fever was moderate grade and intermittent without rigors or night sweats. He developed septic shock and hypoxemic respiratory failure requiring intensive care unit admission. Radiological evaluation demonstrated left lower lobe consolidation with minimal parapneumonic effusion. Bronchoscopy revealed a narrowed bronchial lumen due to an endobronchial mass, raising suspicion for bronchogenic carcinoma. Histopathological examination of bronchoscopic biopsy specimens demonstrated non-branching pseudohyphae consistent with Candida species, confirming invasive pulmonary candidiasis. Blood, sputum, urine, and pleural fluid cultures were negative. The patient improved clinically following antifungal therapy and was discharged home on oral antifungal therapy. Conclusion. This case highlights the diagnostic challenge of invasive pulmonary candidiasis and underscores the indispensable role of histopathology in distinguishing true tissue invasion from colonization. In patients with persistent pneumonia and endobronchial lesions, invasive fungal infection should be considered even in the absence of classical immunosuppression.