Primary colon cancer without gross mucosal tumor: unusual presentation of a common malignancy.

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.

Gastric adenocarcinoma masquerading endoscopically as benign gastric ulcer. A five-year experience.

The pathologic features and five-year survival of patients in whom gastric cancer masquerades at endoscopy as a benign gastric ulcer has been poorly characterized. We reviewed retrospectively all cases of gastric adenocarcinoma in three hospitals for a five-year period. Of 266 patients with gastric adenocarcinoma, 169 (63.5%) had endoscopy with biopsy prior to diagnosis of cancer. In 159 of these 169 patients (94.1%), the endoscopic findings suggested cancer, while in the remaining 10 patients (5.9%) the endoscopic appearance suggested benign ulcer. In six of these 10 patients, the initial endoscopic biopsies did not reveal cancer and correct diagnosis was delayed for as long as 14 months. Three of the 10 patients had "early gastric cancer" by pathologic criteria at gastrectomy, although one had lymph node metastasis. The other seven patients had pathologic criteria for advanced gastric cancer, and three had lymph node metastasis. In spite of advanced cancer and/or lymph node metastasis in eight of our 10 patients, five-year survival in these patients with benign-appearing ulcers was 70%, as compared to 17% in patients whose gastric lesions appeared malignant at endoscopy.