title: Collision tumors of hepatocellular carcinoma and malignant peritoneal mesothelioma.
abstract: We report a case of synchronous hepatocellular carcinoma (HCC) and malignant peritoneal mesothelioma (MM-per). A 56-year-old man with no past history of asbestos exposure, chronic viral hepatitis, or alcoholic liver injury was admitted to our hospital with left flank pain and abdominal tumor. Partial hepatectomy, splenectomy, partial diaphragm resection, and partial gastrectomy were performed. The tumor in the lateral segment of the liver was gray to white, massive in appearance, and contained focal bile-producing nodules and extensive fibrous firm lesion. It had directly invaded the spleen and diaphragm. Liver cirrhosis was not found. The peritoneum contained multiple small nodules especially around the diaphragm, which mimicked carcinoma dissemination. After histological examination, the liver tumor was diagnosed as HCC. It had trabecular and scirrhous patterns and positive immunoreactivities for Hep-Par-1 and α-fetoprotein. The peritoneal nodules were diagnosed as MM-per, epithelioid type, with positive immunoreactivities for calretinin and cytokeratin 5/6. The two tumors collided around the diaphragm. Cases of MM synchronous with other primary malignant tumors have been reported, but most had a history of asbestos exposure unlike the present case. The carcinogenic background was unclear for two tumors in this case. This is an extremely rare and valuable case.
authors.affiliation: Department of Palliative Medicine, Okayama Saiseikai General Hospital, 1-17-18 Ifuku-chou, Kita-ku, Okayama, Okayama, 700-8511, Japan, uemotoj@gmail.com.
authors.forename: Junko
authors.initials: J
authors.lastname: Uemoto
authors.forename: Nobuo
authors.initials: N
authors.lastname: Hoshi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Hirabayashi
authors.forename: Sayuri
authors.initials: S
authors.lastname: Hoshi
authors.forename: Kei
authors.initials: K
authors.lastname: Onodera
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nishi
authors.forename: Moriaki
authors.initials: M
authors.lastname: Tomikawa
authors.forename: Seiji
authors.initials: S
authors.lastname: Igarashi
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000628:therapy; D003131:Combined Modality Therapy; D017809:Fatal Outcome; D006801:Humans; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D008297:Male; D008654:Mesothelioma / Q000000981:diagnostic imaging* / Q000628:therapy; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000000981:diagnostic imaging* / Q000628:therapy; D010534:Peritoneal Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D011859:Radiography