Radiological interpretation of a small cell neuroendocrine cancer of the lung

Neuroendocrine tumors may develop throughout the human body with the majority being found in the gastrointestinal tract and bronchopulmonary system. Neuroendocrine tumors are classified according to the grade of biological aggressiveness (G1–G3) and the extent of differentiation (well-differentiated/ poorly-differentiated). The well-differentiated neoplasms comprise typical (G1) and atypical (G2) carcinoids. Large cell neuroendocrine carcinomas, as well as small cell carcinomas (G3), are poorly-differentiated. The identification and differentiation of atypical from typical carcinoids or large cell neuroendocrine carcinomas and small cell carcinomas are essential for treatment options and prognosis. Pulmonary neuroendocrine tumors are characterized according to the proportion of necrosis, the mitotic activity, palisading, rosette-like structure, trabecular pattern, and organoid nesting. These neuroendocrine tumors of the lung arise from Kulchitzky cells of the bronchial mucosa and comprise typical carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma (LCNEC), and small cell lung cancer (SCLC). Here is a case report of the 75-year-old male patient presented with complaints of a cough and sudden onset of breathlessness and weight. On Computed Tomography (CT) a large heterogeneous lesion noted in the left anterior mediastinum which was subjected to CT guided biopsy. On histopathology and immunohistochemistry, the tumor was confirmed as small cell neuroendocrine tumor.