Pathologic observations of the duodenum in 615 consecutive duodenal specimens in a single Japanese hospital: II. malignant lesions.

The author investigated histopathology of 615 consecutive duodenal specimens in our pathology laboratory in Japan. A computer review of the duodenal specimens was done. In cases of malignancy, histological slides were reviewed. The duodenal specimens were composed of 567 benign lesions (92%) and 48 malignant lesions (8%). The 48 malignant lesions were composed of 20 cases (42%) of primary adenocarcinoma, 10 cases (21%) of primary adenocarcinoma of ampulla Vater, 4 cases (8%) of primary squamous cell carcinoma, 1 (2%) cases of primary spindle cell carcinoma, 4 (8%) cases of carcinoid tumors, 1 (2%) case of malignant lymphoma, and 8 cases (17%) of secondary carcinoma from the pancreatic carcinoma or bile duct carcinoma. The primary adenocarcinoma (n=20) was composed of well differentiated adenocarcinoma (n=9), papillary adenocarcinoma (n=1), moderately differentiated adenocarcinoma (n=6), and poorly differentiated adenocarcinoma (n=4). The primary adenocarcinoma of the ampulla of Vater (n=10) was composed of well differentiated adenocarcinoma (n=7) and moderately differentiated adenocarcinoma (n=3). The primary squamous cell carcinoma (n=4) showed proliferation of malignant squamous cells with keratinization and intercellular bridges. The spindle cell carcinoma (n=1) consisted of only malignant spindle cells immunohistochemistry positive for various cytokeratins and vimentin. The carcinoid tumor (n=4) was typical carcinoid and showed organoid, trabecular, and ribbon-like arrangements. The carcinoid tumor was immunohistochemically positive for neuroendocrine markers such as CD56, neuron-specific enolase and synaptophysin. The malignant lymphoma (n=1) was diffuse large B-cell lymphoma immunohistochemically positive for CD10, CD20, and CD79α. The secondary carcinoma (n=8) was adenocarcinoma invaded from the pancreatic adenocarcinoma (n=6) and extrahepatic bile duct adenocarcinoma (n=2).