Chapter 34 (page 174)

The Pyloric Sphincteric Cylinder in Health and Disease

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Chapter 34 (page 174)

Chapter 34

Malignant Lymphoma

In a historical review of malignant lymphoid tumors of the gastrointestinal tract, Dawson et al (l96l) found that these tumors had been reported more frequently in the stomach than in the remainder of the digestive tract. Up to that time at least 293 reports of lymphoid tumors of the stomach had appeared in the literature, but no clear distinction had been made between lymphomas originating primarily in the stomach and those affecting the stomach as a manifestation of generalized, disseminated lymphomatous disease. According to these authors the tumors could be classified as primary if the following conditions were met: there should be no palpable superficial lymphadenopathy and no enlargement of the mediastinal lymph nodes; the total and differential white blood count should be within normal limits; at laparotomy the bowel (or gastric) lesion should predominate, the only lymph nodes obviously affected being those in its immediate neighbourhood; and finally the liver and spleen should be free of tumor.

Rappaport (l966) proposed a histological classification of the lymphomas which also included Hodgkin's disease. For the past two or three decades his classification, as well as five or six others, have been widely used.

Naqvi et al. (l969) found that approximately 1,200 cases of gastric lymphomas had been recorded, and reviewed 100 cases of their own. In their experience the stomach was the part of the gastrointestinal tract most frequently involved, and the prepyloric region the site most commonly affected.

In discussing the pathology Ming (l973) stated that, in the stomach, malignant lymphoma develops in the mucosa, from where the tumor cells infiltrate the submucosa and muscularis. Seeing that this mode of growth is similar to that of carcinoma, it often assumes the gross characteristics of carcinoma and macroscopic differentiation of the two conditions may be difficult. Grossly the tumors may be ulcerated with rolled borders, while others are polypoid. There may be extensive infiltration and thickening of the gastric wall and/or mucosal folds. Histologically there is dense infiltration, with varying degrees of admixture of mature and immature lymphoid cells and histiocytic (reticulum) cells; there is a lack of fibrous tissue proliferation. While mucosal glands may be absent, the remaining gastric glands usually retain their normal architecture. The presence of reticulum fibres and absence of stainable mucin are features in favour of lymphoma (as opposed to carcinoma).

Katz et al. (l973) described 15 cases of disseminated lymphoma with gastric involvement. The following abnormal findings were noted at gastroscopy: enlarged, nondistensible rugae in 13 cases, multiple superficial ulcerations in 11, nodular ulcerations in 8 and large polypoid masses in 4. Biopsy furnished a positive diagnosis in not more than 2 of the 15 cases. The poor yield was ascribed to the infiltrative submucosal nature of secondary lymphoma and the superficial capacity of endoscopic biopsies. The gastroscopic appearance was found to be of greater help in the diagnosis of gastric lymphoma than biopsies, directed brush cytology or cytology washings.

Meyers et al. (l975) pointed out that the radiographic features of primary gastric lymphoma were not specific and included polypoid masses, ulcerations, thickening of the walls and generalized enlargement of the rugae. These appearances could simulate ulcerated carcinoma, gastric ulceration, granulomatous disease or hypertrophic rugae due to other causes, e.g. Menetrier's disease. While lymphoma may occur anywhere in the stomach, they reiterated that it commonly involved the pyloric and prepyloric area. In 7 proved cases they noted a definite tendency for the condition to spread submucosally from the distal stomach into the duodenum, resulting in radiographically discernible contour deformities, filling defects or ulcerations in the duodenal bulb. These features seldom occur in gastric adenocarcinoma (Chap. 33), and were regarded as characteristic of lymphoma, permitting a specific diagnosis to be made. In one of their cases, which was described in detail, duodenal spread occurred both superficial and deep to the lamina propria. This surrounded, but apparently did not invade, the glands of Brunner.

Koehler et al. (l977) analyzed the records of l9 patients who underwent gastric resection for lymphoma. Three of these had microscopic evidence of invasion of the duodenum, and in one of these the duodenal involvement was evident radiographically and grossly.

Lim et al. (l977) defined primary gastric lymphoma as a tumor apparently originating in the stomach, with no clinical, laboratory or radiographic evidence of systemic involvement at the time of initial evaluation. They analyzed 50 consecutive cases and found the most common localities to be the "antrum", the pyloric area and lesser curvature. According to Rappaport's (1966) classification, the diffuse histiocytic type occurred in 23 of their 50 patients, the well differentiated lymphocytic type in 12, the mixed lymphocytic histiocytic in 5, the poorly differentiated lymphocytic in 5, Hodgkin's disease in 3, and unclassified lymphoma in 2 cases. The prognosis for survival was much better than in gastric carcinoma since the latter condition presented with a far higher incidence of serosal penetration and nodal and distant metastases. The treatment of choice was gastric resection (44 of their cases being resectable), while radiotherapy and chemotherapy constituted additional therapeutic options.

Seeing that the therapy and prognosis of gastric lymphoma differ significantly from those of adenocarcinoma, Hricak et al. (l980) reiterated that correct diagnosis was essential. By reviewing the radiographic and pathological features in 81 cases, they investigated the incidence of spread from the stomach into the oesophagus, and from the stomach into the duodenum. In 60 of the cases the tumor appeared to have originated primarily in the stomach, and only 5 of these showed involvement of adjacent nodes, the mesentery or small bowel. In 21 patients the involvement was mainly extrinsic, the stomach being secondarily involved. Radiographically transpyloric extension was seen in 27 of the 81 cases. In 7 the "antrum" was the only site of tumor involvement, 6 of these showing transpyloric extension. Histologically the tumor was found to have a submucosal origin (according to Ming it originated in the mucosa). Submucosal extension across the pylorus was seen in l9 of the 27 cases.