title: A case of very well-differentiated adenocarcinoma with carcinoid tumor in the ascending colon.
abstract: Malignant tumors with mixed glandular and neuroendocrine characteristics with at least 30% of each component are classified as mixed adenoneuroendocrine carcinoma (MANEC) by the World Health Organization 2010 classification. We report here a case of very well-differentiated adenocarcinoma accompanied by carcinoid tumor, categorized as MANEC. A 41-year-old Japanese man was clinically diagnosed with ascending colon cancer and underwent right hemicolectomy. Using an immunohistologic technique, the pathologic diagnosis was very well-differentiated adenocarcinoma accompanied by carcinoid tumor and marked eosinophil infiltration, which was categorized as MANEC. By immunohistochemical analysis, tumor cells of the carcinoid component exhibited very low proliferation activity. Our case was thought to be MANEC without high malignant potential. MANEC as per the World Health Organization 2010 classification seems to include tumors with diverse grades of malignancy, and it might need to have subclassifications according to the malignancy potential of the tumor cells.
authors.affiliation: 1 Department of Surgery, Social Insurance Gunma Chuo General Hospital, Gunma, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakurai
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Tsukagoshi
authors.forename: Masaki
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tabe
authors.forename: Takaharu
authors.initials: T
authors.lastname: Fukasawa
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Kiriyama
authors.forename: Minoru
authors.initials: M
authors.lastname: Fukuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Naitoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kuwano
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000328:Adult; D002276:Carcinoid Tumor / Q000473:pathology*; D003110:Colonic Neoplasms / Q000473:pathology*; D006801:Humans; D008297:Male; D018193:Neoplasms, Complex and Mixed / Q000473:pathology*