[A case of primary small cell neuroendocrine carcinoma of the liver].

Small cell neuroendocrine carcinoma is a type of undifferentiated, malignant neuroendocrine tumor. Most of neuroendocrine tumors exhibit well-differentiated features and are classified as carcinoid tumors. However, carcinomas of the liver with anaplastic characters, which are classified as small-cell carcinomas are extremely rare and only few cases have been reported in the literature. We report an unusual case of primary small cell neuroendocrine carcinoma of the liver in a 67-year-old man. The patient was found to have a palpable mass on right upper quadrant of abdomen on physical examination. The diagnosis was made by immunohistochemical stains of biopsied specimen from the liver. Other possible primary site was excluded by radiologic and endoscopic evaluations. The tumor was composed of small monotonous and hyperchromatic poorly differentiated cells with higher nuclear to cytoplasmic ratio, and were positive for neuroendocrine tissue markers such as synaptophysin, c-kit, and CD56.