Ampullary adenocarcinomas

FIGURE 15.24 Intestinal-type ampullary adenocarcinomas are diffusely immunoreactive for CDX2 (A). In contrast, pancreatobiliary-type ampullary adenocarcinomas either are negative (B) or exhibit only focal CDX2. 

More than 80% of ampullary epithelial neoplasms are adenocarcinomas. They are seen predominantly in the seventh decade of life and may be associated with polyposis syndromes and neurofibromatosis. Because ampul-iary carcinomas result in early symptoms and detection, they are often relatively small at the time of diagnosis. Most have an exophytic component representing adenoma. ... 

Endocrine cells are commonly found in ampullary adenocarcinomas. Although they may not be evident by routine microscopy, immunohistochemical staining for chromogranin reveals scattered endocrine cells in one third of the cases. The distribution of these neuroendocrine cells is random in some cases they are scattered evenly throughout the tumor, whereas in others they may be clustered. In general, they are more common in intestinal-type or mucinous adenocarcinomas than in pancreatobiliary type. ... 

Other forms of adenocarcinoma that occur in the ampullary region include mucinous adenocarcinoma, signet-ring cell adenocarcinoma, and invasive papillary carcinoma, which may mimic in situ neoplasia because of its exophytic growth, papillae formation,... 

Mutations of p53 have been detected in the majority of ampullary carcinomas with corresponding accumulation of the abnormal product as detected immunohistochem-ically." " EGFR is overexpressed in 50% to 65% of invasive ampullary carcinomas. Pancreatobiliary-type adenocarcinomas are more likely to overexpress EGFR than are intestinal-type tumors. Related growth factors c-erbB-2 and c-erbB-3 are also overexpressed in ampullary carcinoma. 

CK7 is often strongly positive and CK20 more focal in pancreatobiliary-type ampullary adenocarcinomas, whereas intestinal-type ampullary adenocarcinomas tend to have more CK20 and less CK7. 

Sessa F, Furlan D, Zampatti C, et al. Prognostic factors for ampullary adenocarcinomas tumor stage, tumor histology, tumor location, immunohistochemistry and microsatellite instability. Virch Arch. 2007 451 649-657. 

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