Pulmonary Neuroendocrine Carcinoma Diagnosed in a Patient With History of Tuberculosis

Abstract

INTRODUCTION: Pulmonary neuroendocrine tumors comprise of 1-2% of lung cancers with a worldwide incidence of 35/100,000 (1,2). The presentation is non-specific and can be misdiagnosed, often delaying treatment for the disorder. CASE PRESENTATION: We present a 45-year-old female with insidious onset of shortness of breath and dry cough for 6 weeks. She had a past history of incarceration and tuberculosis that was treated in 2003. She denied cigarette smoking, family history of cancer, weight loss or anorexia. Her physical exam was significant for rales auscultated predominantly in the upper lobes bilaterally, without neck vein distension, heart murmur, rub, gallop or pedal edema. Her chest x-ray revealed a left-sided thoracic mass silhouetting the aortic arch with probable left hilar lymphadenopathy noted on the lateral radiograph. A comparative CXR from 2005 revealed the same mass. A CT scan of the thorax further characterized the lung mass as encasing the left hilum and severely narrowing the left pulmonary artery, concerning for adenocarcinoma. The patient was put on respiratory isolation. She was found to be sputum AFB smear positive with a negative nucleic acid amplification test. HIV test was negative and ACE level was normal. Bronchoscopy with transbronchial needle aspiration detected abnormal bronchial mucosa that was friable and bled prior to intervention. Immunohistochemical stains were performed and were positive for CYTOKERATIN AE1/3, CYTOKERATIN 7 (FOCAL), CD56, AND CHROMOGRANIN (FOCAL) A KI-67 (MIB-1) immunostain showed positivity in approximately 30% of tumor cells and confirmed pulmonary neuroendocrine carcinoma. DISCUSSION: Pulmonary neuroendocrine carcinoma of intermediate cell type was diagnosed in a non-smoking female. The presenter will discuss the key elements of diagnosis, presentation and unique treatment in this case. CONCLUSIONS: When assessing a young patient with no smoking history with CT scans concerning for carcinoma, differentials such as pulmonary neuroendocrine carcinoma need to be considered.