Primary neuroendocrine carcinoma ("Merkel cell tumor") of the eyelid: a report of two cases.

BACKGROUND. Merkel cell tumor is an uncommon, aggressive neoplasm of the skin, now regarded as a neuroendocrine carcinoma. Eyelids are among the sites where it can develop, often mimicking a benign process.

Histopathology, hormone products, and clinicopathological profile of endocrine tumors of the upper small intestine: A study of 44 cases.

Forty-two duodenal and 3 upper jejunum tumors from 44 patients were investigated. All tumors were tested immunohistochemically for gastroenteropancreatic hormones and general endocrine cell markers. Twenty-eight of the 45 tumors (62%) proved to be gastrin cell tumors, with (12 cases) or without (16 cases) associated Zollinger-Ellison syndrome.