Causes of pancreatic cysts

Typically, according to their origin and morphological features, four types of pancreatic cysts are distinguished.

The first type is ontogenetic cysts, which are a developmental defect; such cysts are often multiple and often combined with polycystic disease of other organs (lungs, kidneys, liver, etc.), thus representing congenital polycystic disease. Cysts are usually lined inside with single-row cubic epithelium, and their contents are serous and do not contain enzymes.

The second type of cysts is proliferative; their occurrence is caused by the proliferation of the epithelium of the ducts, the lumen of which is significantly expanded. These cysts develop against the background of fibrosis of the pancreatic tissue and are multi-chamber cavities of the cystadenomas type. Sometimes this disease is called "cystic fibrosis" of the pancreas, and some cases are difficult to distinguish from cystic fibrosis.

The next type of pancreatic cysts are retention cysts, which occur due to compression (by a scar, tumor, cyst), growth by a malignant tumor, or blockage (for example, by a stone) of a duct or several ducts of the pancreas. In the occurrence of such cysts, it is believed that concomitant lymphostasis plays a certain role. Cysts of this type are often solitary and have large sizes (up to 10 cm or more), but can also be multiple and small, representing a kind of limited conglomerate of cysts. The contents of the cysts are serous or colloidal.

And finally, the fourth type of cysts are false cysts, sometimes also called pseudocysts. They occur in patients who have had a severe form of hemorrhagic pancreatitis, in the zone or zones of pancreatic tissue necrosis, in some cases - abscesses (if the contents of the abscess have not broken through the fistula into any nearby organ: into the stomach, duodenum, pleural cavity, etc.). In the foci of pancreatic tissue necrosis that occur in hemorrhagic pancreatitis, in the next few hours (with a "favorable" course, i.e. if the patient does not die from this acute severe disease), fibrin first falls out, then a granulation inflammatory shaft forms around the necrosis, which then turns into a dense fibrous capsule. The number and size of pseudocysts in different patients may be different. In chronic recurrent pancreatitis, after severe exacerbations, necrotic foci may form again and new cysts may appear. But more often there are one or two cysts, less often - multiple pseudocysts. Sometimes such pseudocysts reach very large sizes, displacing neighboring organs (stomach, transverse colon, spleen). The size of pseudocysts is determined by a number of factors: the size of the necrotic foci formed due to the disintegration of tissue in these areas by osmotically active substances that help "attract" fluid from the surrounding tissue (interstitial fluid, lymph); in the case of erosion of a sufficiently large blood vessel, blood enters the cyst. Finally, of great importance is maintaining the connection with the duct (or ducts) through which pancreatic juice secreted by healthy areas of tissue enters the cyst, and the possibility of outflow of the cyst contents into larger ducts and the duodenum. It is believed that after acute hemorrhagic (necrotic) pancreatitis, one or more pseudocysts are formed in approximately half of the cases, especially often in alcoholic pancreatitis. It should be noted that cysts of the first three types are much less common: according to various authors, in 0.01-0.07% of cases.

We should not forget other reasons for the formation of pancreatic cysts - as a result of abdominal trauma, the development of echinococcus (the latter, however, are rare in this organ), etc.

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