title: Synchronous occurrence of advanced neuroendocrine carcinoma and tubular adenocarcinoma of the rectum.
abstract: This report presents a rare case with the synchronous occurrence of advanced neuroendocrine carcinoma (NEC) and tubular adenocarcinoma of the rectum. A 52-year-old Japanese male presented with general fatigue and bloody stool. Endoscopic examination showed an ulcerated lesion of the lower rectum. The pathological diagnosis of biopsy specimens from this lesion indicated moderately differentiated adenocarcinoma. He was referred to the surgical outpatient clinic with advanced rectal cancer. Barium enema indicated two lesions in the upper and lower rectum. Computed tomography revealed multiple hepatic metastases. A low anterior resection was performed with lymph node dissection. The resected specimen indicated an elevated lesion with ulceration in the upper rectum and an ulcerated lesion in the lower rectum. Histopathological and immunohistochemical analyses revealed NEC from the upper rectum and moderately differentiated tubular adenocarcinoma from the lower rectum. These two lesions were completely separated from each other. Therefore, this case demonstrates the synchronous occurrence of advanced NEC and tubular adenocarcinoma in the rectum.
authors.affiliation: Department of Surgery 1, School of Medicine, Kitakyushu, Japan ; Department of Gastroenterological and General Surgery, Wakamatsu Hospital of University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Takayuki
authors.initials: T
authors.lastname: Torigoe
authors.forename: Noritaka
authors.initials: N
authors.lastname: Minagawa
authors.forename: Toshihito
authors.initials: T
authors.lastname: Uehara
authors.forename: Koji
authors.initials: K
authors.lastname: Yamaguchi
keywords: Neuroendocrine carcinoma; Rectum; Small cell type; Synchronous occurrence; Tubular adenocarcinoma