Chapter 33 (page 163)

The Pyloric Sphincteric Cylinder in Health and Disease

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Chapter 33 (page 163)

In gastric colloid carcinoma, the characteristics of spread in the gastric wall resembled those of adenocarcinoma in some cases, and mucinous scirrhus carcinoma in others. On the whole the greatest spread occurred in the submucous layer. In 2 cases infiltration of the duodenum had occurred, but further particulars of these were not given. The results seemed to justify the conclusion that the less differentiated carcinomas spread more readily to the duodenum than the highly differentiated tumors. In addition, the tendency to spread in the various layers of the wall was stronger in the stomach than in the duodenum.

In a wide-ranging study of gastrectomy specimens obtained from cases of gastric carcinoma, Eker and Efskind (1960) found the following: In 865 partially resected stomachs infiltration of the lower border was seen in 2.4 percent. In 256 totally resected stomachs infiltration of the lower border was present in 0.8 percent. Tumors involving the sphincteric cylinder (both adenocarcinoma and scirrhus carcinoma) infiltrated the lower border in 3.6 percent. The rarity with which distal extension of tumor occurred was ascribed to a barrier effect of the pyloric "sphincter", or to different peristaltic effects in the duodenum.

Majima et al. (l964) examined 833 subtotal resection specimens of cases of gastric carcinoma. Duodenal invasion was encountered in 151 cases (18.1 percent); the frequency of duodenal invasion depended on the location of the tumor in the stomach. If only those tumors within 1.0cm of the pyloric ring were considered, the incidence of duodenal invasion was 37.0 percent. In cases where the gastric tumor was located 3.0 to 4.0 cm proximal to the ring, the incidence was 4.1 percent. (Almost all these cases were associated with spread of carcinoma to other structures, e.g. the peritoneum and lymph nodes).

Of the cases with duodenal invasion, the serosa of the duodenum was involved in 115 (76.2 percent); in none of these cases could a continuous extension into the mucosal coat of the duodenum be demonstrated. However, in a few cases carcinoma of the prepyloric region extended directly into the duodenal submucosa at an early stage, in the absence of extragastric spread. In 92 percent of cases the extent of spread into the duodenum was 1.0 cm or less. In 6.6 percent it was between 1.0 and 2.0 cm, and in 0.7 percent it varied from 2.0 to 2.4 cm. In some of these cases the line of division of the duodenum was involved by carcinomatous infiltration, indicating that the duodenal invasion extended further than the distance given. The pattern of duodenal invasion was continuous in 54 percent of cases, discrete in 34 percent, and both continuous and discrete in 10 percent. In the 5 cases of duodenal mucosal invasion, spread had occurred via the lymphatic channels and not through continuous direct extension.

Fernet et al. (l965) described 7 cases of scirrhous carcinoma of the stomach (linitis plastica) which had spread within the wall of long segments of the alimentary tract, producing an appearance of leathered induration similar to that seen in the stomach. Occasionally the process extended downward as far as the sigmoid colon. This tubal spread was due to a neoplastic infiltrate in the intramural tissue spaces, producing a diffuse induration and separation of the mucosa, submucosa and muscularis. Spread occurred in the longitudinal lymph channels, mainly in the submucosa and subserosa, leaving the muscular layer relatively intact; the lymph spaces were clogged with small round or oval undifferentiated cells with a positive mucin reaction. Metastatic spread also occurred to the mesenteric lymph nodes and the intestinal serosa. It appeared as if the longitudinal spread in linitis plastica was quite different from that of glandular carcinoma, as the appearance of leathered induration was not observed in well- differentiated adenocarcinoma. Tubal spread seemed to occur only in linitus plastica or similar undifferentiated forms of carcinoma. No detailed description of conditions at the pyloro-duodenal junction in these cases was given.

Paramanandhan (l967) reviewed the literature on duodenal spread of gastric carcinoma for the period 1865 to 1965, and found great variations in the reported incidences. He studied the frequency and extent of duodenal invasion in 29 necropsy specimens of gastric adenocarcinoma. Invasion of the serosa and lymph nodes was apparent in all cases. The subpyloric group of lymph nodes was involved in 24 cases, 20 of these showing invasion of the duodenum. Thus duodenal spread had occurred in 20 of the 29 cases, giving an incidence of 68.9 percent. There was a discrepancy between the macroscopic and microscopic appearances, as only 3 of the 20 cases showed macroscopic evidence of duodenal invasion. Microscopically the spread often involved the duodenal mucosa and submucosa. The submucosal layer was the most frequently affected, being followed by the serosa and the other layers of the wall. In 17 cases duodenal invasion occurred chiefly via the lymphatics, but it was difficult to determine whether this was primarily via the submucous or via the subserosal lymph vessels. In 3 cases extension appeared to be by direct infiltration of sheets of anaplastic cells. The duodenal surface epithelium appeared to remain intact. Although they were often compressed by dilated lymphatics containing tumor cells, Brunner's glands appeared to be particularly resistant. In all cases there was some degree of lymphocytic infiltration of the duodenum, due to lymphatic stasis. As all cases with duodenal invasion showed involvement of the subpyloric group of glands, spread could be due to a downward or retrograde lymph flow resulting from a block of the nodes. The extent of duodenal spread varied from 0.5 cm to 22.6 cm. In more than half the cases no tumor tissue occurred beyond the first 3.0 cm of the duodenum, while in one case extension was seen for a distance of 22.6 cm.

In discussing the pathology and prognosis of carcinoma of the stomach, Hawley et al. (l970) analyzed the findings in 205 patients who underwent total or partial gastrectomy. Cases were divided into the following types: (1) well-differentiated adenocarcinoma; (2) poorly differentiated or anaplastic carcinoma; (3) linitis plastica type. One of the difficulties in the grading was the great variability in the degree of cellular differentiation in different parts of the same tumor. The amount of lymphocytic and plasma cell infiltration had a significant effect on the prognosis; five out of 7 patients with a heavy infiltration of such cells survived over 5 years. The feature with the worst influence on prognosis was lymph gland involvement. Linitis plastica was a type of carcinoma which had to be considered separately; here submucosal and muscular infiltration involved part or all of the stomach, sometimes without mucosal ulceration. Three cases of mucosal carcinoma, in which areas of malignant change were confined to the mucous membrane, were encountered; these were discovered incidentally during histological examinations of gastrectomy specimens removed for peptic ulceration.