Gallbladder Small Cell Neuroendocrine Carcinoma

**Semantic type:** Neoplastic Process

**Definition:** An aggressive high-grade carcinoma with neuroendocrine differentiation that arises from the gallbladder and is composed of malignant small cells. The mitotic count is more than 20 per 2 mm2 and/or the Ki-67 index is more than 20%.

**Synonyms:** - Gallbladder Oat Cell Carcinoma - Gallbladder Small Cell Carcinoma - Gallbladder Small Cell NEC - Oat Cell Carcinoma of Gallbladder - Oat Cell Carcinoma of the Gallbladder - Small Cell Carcinoma of Gallbladder - Small Cell Carcinoma of the Gallbladder