Primary colorectal signet-ring cell carcinoma in young patients: report of 3 cases.

Three cases of primary signet-ring cell carcinoma of the rectum are described. They accounted for 0.2% of the 1531 cases of colorectal adenocarcinoma in the 12 yr period from 1972-1983 in the University Department of Pathology at Queen Mary Hospital. The patients were young, aged 18, 24 and 27 yr respectively, in striking contrast to the mean age of 62 in patients with the usual types of colorectal cancer. They were also younger than most patients with this tumour in the literature. They presented with alteration of bowel habit, blood and mucus in stool, and weight loss. Pathological features included constrictive narrowing of the gut lumen by intestinal wall thickened by a desmoplastic reaction to diffusely infiltrating signet-ring carcinoma cells, widespread lymph node and peritoneal metastases, and absent hepatic metastasis. Microscopically, the mucosa was largely intact, but had multifocal tumour involvement. This peculiar feature was responsible for three consecutive negative biopsies in one case. Care in distinguishing it from mucinous adenocarcinoma is emphasized. All three patients presented with Dukes' C lesions. The prognosis is poor.