Adenosquamous Carcinoma of the Duodenal Third Portion

Small intestine cancers are uncommon diseases among gastrointestinal cancers. Among these small intestine cancers, adenocarcinoma is the most common type. Other types of cancers often found in the small intestine are carcinoid, lymphoma, sarcoma, and gastrointestinal stromal tumor. Adenosquamous carcinomas of the duodenum are extremely rare lesions among small intestine cancers, and only a few cases have been reported so far. In these reported cases, tumors arose from the ampulla of Vater, periampullary portion, or duodenal fourth portion. Never has an adenosquamous carcinoma been reported to arise from the duodenal third portion. Herein, we present such a case. Correspondence Author to: Chen-Te Chou Department of Medical Imaging, Changhua Christian Hospital, Changhua, Taiwan No. 135, Nan-Sian Street, Changhua 500, Taiwan J Radiol Sci 2011; 36: 119-123 Adenosquamous carcinoma 120 J Radiol Sci June 2011 Vol.36 No.2 revealed a huge isodense enhancing tumor in the duodenal 3rd portion, measuring 8.1 × 5.3 cm, with anterosuperior displacement and suspicious invasion of the pancreatic head (Fig. 2). Several small (< 1 cm) lymph nodes were found in the peri-pancreatic and peri-duodenal regions. Otherwise, no prominent liver metastases or intestinal obstruction was noted on this abdominal CT. Pancreaticoduodenectomy, cholecystojejunostomy, and pancreaticojejunotomy were done. The pathologic diagnosis was adenosquamous carcinoma of the duodenum, which had invaded to the pancreas. The tumor was made up of biphasic components, including poorly differentiated adenocarcinoma and moderately differentiated squamous cell carcinoma. These two components were mixed together without clear border (Fig. 3a). The poorly differentiated adenocarcinoma was composed of single cells or signet ring cells containing intracytoplasmic mucin, and the moderately differentiated squamous cell carcinoma revealed keratinized polygonal cells arranged in nests (Fig. 3b). Immunohistochemically, the tumor cells were diffuse positive for cytokeratin 7, and the squamous part was reactive for cytokeratin 5/6 and p63. The special stain of d-PAS demonstrated the intracytoplasmic mucin in the signet ring cells. The immunophenotype was also compatible with adenosquamous carcinoma.