Primary malignant epithelial tumors of the small bowel.

Abstract

Primary Malignant tumors of the small intestine are admittedly rare but the recognized incidence is increasing, due largely to improved diagnostic facilities and a renewed interest, during the last decade, in small bowel studies. Accurate clinical recognition of small bowel disturbance in day-by-day practice is still uncommon (14), and only 25 per cent of the tumors are definitely diagnosed on roentgen examination (2), though no other procedure approaches this in accuracy. Incidence In a review of material in the Department of Surgical Pathology at the Presbyterian Hospital, New York City, Swenson, in 1943, found 9 carcinomas of the jejunum and 5 of the ileum (13). The absence of carcinoma of the duodenum in his study is noticeable. The records of the University Hospitals of Cleveland, from 1933 to 1946, show 14 cases of primary carcinoma of the small bowel, i.e., about one case to 3,000 admissions on the surgical service or to 9,000 general hospital admissions (10). According to Ewing (12), only 3 per cent of all malignant tumors in the gastrointestinal tract occur in the small bowel. At the Cook County Hospital, Chicago, 7 cases of carcinoma of the small bowel (3 duodenal and 4 jejunal) were found in 10,309 necropsies, while comparative records showed 273 carcinomas of the stomach and 163 involving the colon (5). Males are more commonly affected than females, in a ratio of 2 or 3 to 1. Dixon (8) and others found the incidence of duodenal tumors to be highest between fifty and seventy years of age. Bockus (1) reports that small bowel tumors generally occur in patients about ten years younger than this. Various theories are propounded to account for the relative infrequency of carcinoma of the small bowel. These include the lack of abrupt angulations in this part of the intestinal tract, the fluid character of the contents, absence of stasis, the alkalinity of the contents, the effect of the secretions, and the absence of sudden changes in the type of epithelium such as occur elsewhere in the gastro-intestinal canal (4, 5). Pathology The primary malignant lesions in the duodenum are of the carcinomatous type, while those in the jejunum and ileum include carcinoma, carcinoid, and malignant melanoma. Dixon (8) and others report approximately equal distribution of the lesions in the first, second, and third portions of the duodenum, though most observers have found the third portion to be involved less frequently than the proximal portion (9, 12, 17). The duodenal lesions are usually infiltrating and constricting, although occasionally a fungating tumor is found in the second portion. There is definite evidence that a chronic uIcer of the first portion of the duodenum may be a precursor of carcinoma (12). In these cases the type of neoplasm is very similar to carcinoma of the stomach.