This brief review of the lymphatic system of the stomach and its principal connections serves to illustrate three important points. In the first place, the stomach itself would seem to be naturally divided into three lymphatic areas, each of which is provided with a separate set of glands. The upper or superior area corresponds to the upper halves of both surfaces from the pylorus to the junction of the central third with the fundus, and is drained by the vessels which proceed to the superior gastric glands. The inferior area includes the lower halves of the pyloric and central portions of the viscus, and its lymphatics pass to the inferior gastric glands ; while the fundus, or left area of the organ, is connected with the glands situated at the hilus of the spleen. In the second place, the cceliac glands, by receiving the efferent vessels of each of these groups, are not only liable themselves to become invaded by cancer of any part of the stomach, but also to act as a centre for the distribution of infection to the other lymphatic systems with which they are immediately connected. Finally, the receptaculum chyli, being the reservoir into which the cceliac glands pour their lymph, tends to infect the mesenteric and lumbar glands and the various tributaries of the thoracic duct. The superior gastric glands are more often affected than the other groups, by reason of the abnormal frequency of carcinoma in the upper segment of the stomach. As a rule every member of the series is more or less implicated, but should the primary growth be limited to the cardiac orifice only one or two of the nearest may show signs of enlargement, since the lymphatics of this region pass directly to the cceliac group. Secondary carcinoma of the glands along the lesser curvature often leads to disease of those in the portal fissure, which in their turn diffuse the infection through the superficial lymphatics of the liver to the diaphragm and the pleurae. That this mode of extension is of considerable importance is shown by the fact that in 34 per cent, of our cases where the superior gastric glands were diseased miliary growths were present upon the lower surface of the diaphragm.
Carcinoma of the pylorus usually involves both the upper and lower systems of lymphatics, and, besides giving rise to enlargement of the superior chain of glands, leads to direct infection of the cceliac group by the efferent vessels of the inferior chain which pass behind the pylorus. This fact indicates that any operation devised for the excision of a pyloric growth must include the removal not only of the superficial glands, but also of those which are clustered behind the organ and around the cceliac axis.
The inferior gastric glands are chiefly involved when the neoplasm affects the great curvature. Occasionally their enlargement gives rise to a growth between the stomach and the colon, which invades the bowel, or, by exerting pressure upon a nutrient vessel, induces gangrene of its walls (Goullioud and Mallard). More frequently the mischief spreads into the lymphatics of the great omentum, and converts that tissue into a sausage-shaped mass, which lies transversely across the epigastrium upon the anterior surface of the stomach.
Extension of the disease to the general peritoneum is accompanied by the formation of numerous discrete nodules upon the surface of the serous membrane, which vary from the size of a hempseed to that of a walnut. This cancerous peritonitis, besides being one of the chief causes of ascites in gastric carcinoma, is also responsible for several phenomena of clinical interest. In the first place, it is liable, like other varieties of peritonitis, to produce infection of the lymphatics of the diaphragm, or to be followed by carcinosis of the pleurae and pericardium. Secondly, its invasion of the mesentery and the mesocolon may be accompanied by so much contraction of these structures that the intestines are drawn backwards to the spine and their presence obscured by the coexisting ascites. Thirdly, the inflammation occasionally extends into the subserous areolar tissue, which becomes greatly indurated and thickened, and not only gives rise to compression of the bloodvessels it contains, but may even produce obstruction of the ureters (Bouveret). Fourthly, a large peritoneal growth in the pelvis often contracts adhesions with the neighbouring viscera, the tissues of which it subsequently invades and destroys. In this manner the ovaries, uterus, rectum, bladder, or prostate may become the seat of a secondary disease, the symptoms of which may quite overshadow those of the primary growth. Finally, disease of the peritoneum in the upper part of the abdomen is not infrequently followed by an invasion of the abdominal parietes or by secondary deposits in the skin. In the former case the neoplasm usually spreads to the linea alba, and produces a line of thickening which extends from the ensiform cartilage to the navel, or even to the pubes. In the latter the lymphatics of the round or of the falciform ligament convey the disease to the umbilicus, which becomes retracted and fixed, and may subsequently present one or more cutaneous nodules. This condition is sometimes associated with multiple growths in the subcutaneous tissue of the abdomen, back, or thorax, which are usually ascribed to infection of the systemic arteries. As, however, this explanation does not account for the limitation of the disease to the trunk, we prefer to attribute it to a direct extension by the parietal lymphatics ; and, in two cases where the skin of the thorax exhibited numerous nodules, we were able to prove after death that the mischief had spread from the anterior mediastinum into the intercostal glands, and thence into the intercostal lymphatic vessels.
The cceliac glands constitute an important intermediate centre between the stomach and the receptaculum chyli. They are often much enlarged in growths of the cardia and of the posterior wall, and sometimes form a nodular tumour, which can be detected during life. Softening and ulceration of their substance may lead to occlusion of the inferior vena cava or to destruction of the vertebral column (Brun). In nearly every case they transmit the disease to their pancreatic, hepatic, and splenic tributaries.
Invasion of the receptaculum chyli marks the last stage in the process of lymphatic infection. Through the medium of this reservoir the disease may be propagated backwards to the mesenteric, lumbar, and sacral glands, and thence to those situated along the course of the iliac vessels and in the inguinal region. Extension of the mischief in an upward direction takes place through the thoracic duct, which is sometimes found to be diseased throughout its entire length or occluded by masses of cancer cells (Fenger).
This condition is usually associated with extensive infiltration of the glands in the posterior mediastinum and of those at the roots of the lungs and at the bifurcation of the trachea. In about 3 per cent, of all cases of gastric cancer a glandular enlargement occurs above the left clavicle, owing to the infection of the cervical tributaries of the thoracic duct, while in rare cases a similar condition above the right clavicle indicates the involvement of the right lymphatic duct.