Atypical bronchial carcinoid with postobstructive mycobacterial infection: case report and review of literature.

Background: Pulmonary carcinoids are included in the group of neuroendocrine tumors (NET) and derive from pulmonary neuroendocrine cells. The incidence of these tumors is increasing, but disease awareness remains low among clinicians. The synchronous presentation of lung cancer and mycobacterial infection is well known but the combination of pulmonary carcinoid and mycobacterial infection is rare.
Case Presentation: We treated a 45-year-old female who presented with recurrent pneumonia. Chest X-ray showed a consolidation in the left upper lobe. The patient was treated with various courses of antibiotics without full recovery after six months. Computed tomography (CT) scan demonstrated a central mass in the left upper lobe. Bronchoscopy revealed an endobronchial, well-defined lesion that totally obstructed the left upper lobe bronchus. Bronchial biopsy showed typical carcinoid tumor. Rigid bronchoscopy with electrocautery was attempted, but we were unable to radically remove the tumor. Therefore lobectomy was performed. The surgical pathology specimen showed atypical bronchial carcinoid and consolidations in the lung parenchyma with granulomatous inflammation distally of the bronchial obstruction. Ziehl-Neelsen staining demonstrated acid fast bacilli indicative of mycobacterial infection.
Conclusions: This case history illustrates the importance of careful surgical pathologic examination, not only of the resected tumor, but also of the postobstructive lung parenchyma. Specific postobstructive infections such as tuberculosis or nontuberculous mycobacteria (NTM) can have clinical implications.