Large cell neuroendocrine tumor of the lung: A diagnostic challenge

Lung neuroendocrine carcinoma (NEC) is a rare heterogeneous carcinoma with NE cells in the pulmonary and bronchial epithelium as the site of origin. We describe a case of large cell NEC (LCNEC) in a 55-year-old male, smoker with 25 pack-years, who presented with cough, dyspnea, hemoptysis, and loss of appetite for 6 months. There was no diabetes, hypertension, asthma, chronic obstructive pulmonary disease, tuberculosis, or contact with tuberculosis or malignancy. The presence of a large homogenous mass lesion in the right chest on chest X-ray, further clearly defined on chest computed tomography scan (130/94/123 mm) was suggestive of huge mass. There was no mediastinal or pleural involvement. Possibility of LCNEC was suspected as the ultrasound-guided biopsy was indicating the presence of poorly differentiated carcinoma. Immunohistochemistry was negative for thyroid transcription factor, cytokeratin 7 but was positive for synaptophysin and P40, suggestive of high-grade LCNECs. It was in T4N0M0, stage 3A and treatment with combination chemotherapy was initiated.