Lung Neuroendocrine Tumor

**Semantic type:** Neoplastic Process

**Definition:** A well-differentiated neuroendocrine neoplasm that arises from the lung. It is characterized by the presence of uniform polygonal cells with small or moderate amount of cytoplasm and inconspicuous nucleoli. The cells are usually arranged in organoid and trabecular patterns. It is classified as grade 1 (G1-typical carcinoid tumor) or grade 2 (G2-atypical carcinoid tumor) based on the number of mitotic figures and the absence or presence of necrosis. Grade 2 neuroendocrine tumors have a worse prognosis.

**Synonyms:** - Carcinoid Tumor of Lung - Carcinoid Tumor of the Lung - Lung Carcinoid Tumor - Lung Carcinoid Tumor - Lung Carcinoid Tumor - Lung Carcinoid Tumor - Lung NET - Pulmonary Carcinoid Tumor