Hepatoid adenocarcinoma of distal ileum without inflammatory bowel disease; A rare case

Abstract Hepatoid adenocarcinoma is known to be a variant of AFP-producing adenocarcinoma, and mostly occurs in the stomach. Hepatoid adenocarcinoma originating in the small intestine is extremely rare. We report herein a case of hepatoid adenocarcinoma without inflammatory bowel disease in the distal ileum. A 72-old Japanese female had an ileal tumor with peritoneal dissemination. Partial resection of ileum was performed. The cut surface of the tumor showed a pale-tan-colored solid tumor. Histologically, the tumor consisted trabecular or pseudoglandular proliferation of large polygonal cells, and resembled hepatocellular carcinoma. Thus, metastatic hepatocellular carcinoma was considered with increased serum AFP and PIVKA-II. However, image analysis failed to detect mass lesion in the liver. Hepatoid adenocarcinoma was made by histopathologic and immunohistochemical study, especially using AFP, glypican 3 and HepPar1 immunostaining. The patient did not have a history of any inflammatory bowel disease. After the operation, sorafenib followed by lenvatinib was administered. Thereafter, she has been alive with peritoneal nodules decreasing in size.