It is difficult to include in any description all of the various and complicated lesions which may result from perforation by gastric ulcer of all of the coats of the stomach. The consequences of perforation may be conveniently classified as follows:
1. Some solid organ, usually the pancreas, the liver, or the lymphatic glands, may close the hole in the stomach.
2. An intra-peritoneal sac shut in by adhesions may communicate through the ulcer with the cavity of the stomach.
3. A fistulous communication may form either between the stomach and the exterior (external gastric fistula) or between the stomach and some hollow viscus (internal gastric fistula).
4. The ulcer may perforate into the general peritoneal cavity.
These lesions may be variously combined with each other. It is to be noted that in the first three varieties protective adhesions are present, and that in the last these adhesions are either absent or ruptured.
When the pancreas, the liver, or the spleen form the floor of the ulcer, they may be protected from extension of the ulcerative process by a new growth of fibrous tissue extending from the floor of the ulcer a variable depth into these organs. Sometimes, however, the ulcerative process, aided doubtless by the corroding action of the gastric juice, eats out large excavations in these organs. These excavations communicate with the cavity of the stomach, and are usually filled with ichorous pus. The pancreas, unlike the spleen and the liver, possesses comparative immunity against this invasion by the ulcerative process.
The situation, the form, and the extent of circumscribed peritoneal abscesses resulting from perforation of gastric ulcer depend upon the parts with which the stomach has contracted adhesions. Should an ulcer on the posterior wall of the stomach perforate before the formation of adhesions, the perforation would of course be directly into the lesser peritoneal cavity. An interesting example of this rare occurrence has been communicated by Chiari.73 In this case, the foramen of Winslow being closed by adhesions, the lesser peritoneal cavity which communicated with a gastric ulcer was filled with ichorous pus, and in this floated the pancreas, which had necrosed in mass and had separated as a sequestrum. That form of intra-peritoneal abscess known as subphrenic pneumo-pyothorax has been already described under Symptomatology. Peritoneal abscesses communicating with the stomach may open into various places, as into the general peritoneal cavity, into the pleural cavity, into the retro-peritoneal tissue, through the abdominal or thoracic walls, etc.
73 Wiener med. Wochenschr., 1876, No. 13.
Gastro-cutaneous fistulæ are a rare result of the perforation of gastric ulcer.74 The external opening is most frequently in the umbilical region, but it may be in the epigastric or in the left hypochondriac region or between the ribs. Fistulous communications resulting from the perforation of gastric ulcer have been formed between the stomach and one or more of the following hollow viscera or cavities: the colon, the duodenum and other parts of the small intestine, the gall-bladder, the common bile-duct, the pancreatic duct, the pleura, the lung, the left bronchus, the pericardium, and the left ventricle. Gastro-colic fistulæ, in contrast to gastro-cutaneous fistulæ, are more frequently produced by cancer than by ulcer of the stomach.75 In rare instances the peritoneum over ulcers of the lesser curvature has contracted adhesions with the pyloric portion of the stomach or with the first part of the duodenum. To accomplish this it is necessary that a sharp bend in the lesser curvature should take place. By extension of the ulcerative process abnormal communication is established between the left and the right half of the stomach or between the stomach and the duodenum. In either case the right half of the stomach is often converted into a large blind diverticulum, the digested food passing through the abnormal opening.76 Gastro-duodenal fistulæ are more frequently with the third than with the first part of the duodenum. In one of Starcke's cases the stomach communicated with the colon and through the medium of a subphrenic abscess with the left lung.77