The authors describe a 62-year-old female patient who presented with a progressively enlarging cavitary lesion in the right upper lobe of the lung. Acid-fast bacilli were recovered from a bronchial washing fluid and identified as Mycobacterium tuberculosis. She received antituberculous therapy for 5 months without improvement in her clinical symptoms and chest radiograph. A lobectomy was performed and pathological review demonstrated a high-grade mucoepidermoid lung carcinoma with extensive central necrosis. Staging revealed metastases in her left adrenal gland, kidney and spine. High-grade mucoepidermoid carcinoma of the lung may present as a cavitary lesion. The presence of M. tuberculosis should not preclude clinicians from pursuing adequate diagnostic procedures for a possible malignant lesion.

Keywords: Mucoepidermoid lung carcinoma, Pulmonary tuberculosis