title: Primary colon cancer without gross mucosal tumor: unusual presentation of a common malignancy.
abstract: Colon cancer typically arises in the colonic lumen, allowing for endoscopic detection of cancerous and premalignant lesions. In the case presented, a 73-year-old man with iron deficiency anemia had two colonoscopies showing only diverticula and internal hemorrhoids. Three years later, when the patient complained of dull, intermittent lower abdominal pain, a third colonoscopy identified diverticula, three adenomatous polyps, and no other abnormality. Computed tomography (CT) of the abdomen revealed a 5 cm x 6 cm pericolic fluid collection, which was later found to communicate with the sigmoid colon. The surgical specimen from a partial colectomy contained a distal sigmoid perforation with a 2.5 cm moderately differentiated adenocarcinoma in the underlying submucosal tissue. There was no gross intraluminal tumor. Histopathology, including immunohistochemistry, was consistent with colonic adenocarcinoma. Primary colon cancer grossly sparing the mucosa is an unusual presentation for this common malignancy.
authors.affiliation: Department of Medicine, Wilford Hall Medical Center, Lackland Air Force Base, San Antonio, Tex 78236, USA.
authors.forename: A P
authors.initials: AP
authors.lastname: Wimmer
authors.forename: J P
authors.initials: JP
authors.lastname: Bouffard
authors.forename: P R
authors.initials: PR
authors.lastname: Storms
authors.forename: J A
authors.initials: JA
authors.lastname: Pilcher
authors.forename: C Y
authors.initials: CY
authors.lastname: Liang
authors.forename: J J
authors.initials: JJ
authors.lastname: DeGuide
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D000368:Aged; D003082:Colectomy; D003110:Colonic Neoplasms / Q000175:diagnosis*; D003113:Colonoscopy; D004241:Diverticulum, Colon / Q000175:diagnosis; D006484:Hemorrhoids / Q000175:diagnosis; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000473:pathology; D007417:Intestinal Polyps / Q000175:diagnosis; D008297:Male; D012811:Sigmoid Neoplasms / Q000175:diagnosis