Etiology.—The generally accepted theory as to the cause of pancreatic cysts is, that they are due to retention of the gland secretion, the outflow being prevented in various ways; thus the obstruction of Wirsung's duct may be from without, and may be due to an extension of catarrhal condition of the duodenum, or to duodenal tumors compressing the duct, or the pressure may arise from gall-stones in the common duct. Most frequently, however, it is from within, and is caused by chronic indurative pancreatitis, which compresses and occludes the main duct and its branches.
Concretions may also obstruct the ducts so as to cause retention of their secretion. Dr. Senn, after a number of experiments in ligating the duct in various animals, failed to produce a cyst by thus obstructing the flow, and he therefore believes that the cysts are due, not so much to the retention of the secretion as to its non-absorption, either by an admixture of pathologic non-absorbable substances or by a lessened activity of the absorbing vessels. Trauma should also be mentioned as a cause.
Pathology.—"Cysts of the pancreas may be divided into two orders, monocysts and polycysts, and vary in size and shape, the single being much larger than the multiple. They range from the size of an egg to that of a child's head, or even larger, and may contain as much as twenty quarts of fluid. The cyst wall is composed of dense, firm,-fibrous connective tissue, poor in cells. The lining of its walls is smooth, shiny, and free from epithelium.
"The contents of the cyst is a viscid or watery alkaline fluid of a grayish or reddish-yellow color, and with a specific gravity of 1010 to 1024. The fluid contains leucocytes, red blood-corpuscles, fatty degenerated epithelial cells, free fat, and crystals of fatty acids and cholesterin. The cystic fluid generally presents some or all the characteristics of pancreatic juice; viz., the power to emulsify fat, to transform starch into glucose, and to digest albumin and fibrin." (Fitz.)
Symptoms.—There may not be any symptoms preceding the appearance of the tumor, nor until it has reached considerable size, although usually there will ,be paroxysms of pain in the epigastrium or left chest, extending to the shoulder. Vomiting, belching, and diarrhea may attend these attacks. As the cysts increase in size, the patient loses flesh, and where the tumor is very large, emaciation is a marked feature. Fatty or greasy clay-colored and offensive stools, containing muscular fibers, are sometimes present. Very large cysts, owing to pressure on the liver, are accompanied sometimes by jaundice and ascites. Albumin and sugar, although not constant, were found in a number of cases.
Intestinal hemorrhage is not uncommon. When the tumor is very large, dyspnea occurs, due to pressure. The presence of the tumor mass is the most characteristic feature of a pancreatic cyst, and causes protrusion of the upper part of the abdomen, the enlargement being more to the left. The tumor is smooth, globular, resistant, not elastic, unless very large, and changing its position with the movements of the diaphragm. Fluctuation is readily obtained where the cyst contains large quantities of fluid.
Diagnosis.—This depends entirely upon the knowledge gained by physical examination.
The presence of a smooth, globular tumor in the epigastrium or left hypochondrium, with a resonant zone between the liver and spleen, would suggest pancreatic cyst. By inflating the stomach, the tumor is found behind and below this organ. On aspiration, an alkaline fluid is obtained that "emulsifies fat, saccharifies starch, and more rarely peptonizes albumin."
When the cysts are enormous in size, they might be mistaken for ovarian cysts; but the history of the latter disease, showing a gradual enlargement from below upward, would suggest the difference between the cysts.
Prognosis.—The success that has attended operative treatment renders the prognosis quite favorable.
Treatment.—This is distinctly surgical, and consists in draining the cyst, or in extirpation.
The Eclectic Practice of Medicine, 1907, was written by Rolla L. Thomas, M. S., M. D.