Mesenteric cysts

Mesenteric cysts

Cysts may occur in any region of the mesentery ( Figure 65.16 ). They are most often observed in mesentery adjoining the small intestine (60%) or the colon (40%) and can be classified as follows: /uni25CF chylolymphatic; /uni25CF enterogenous; /uni25CF traumatic; /uni25CF hydatid. Chylolymphatic cysts Although mesenteric cysts are rare, this is the most common - variety , probably arising in congenitally misplaced lymphatic tissue that has no e ff erent communication with the lymphatic system (most frequently in the mesentery of the ileum). The thin wall of the cyst, which is composed of connective tissue ). The

Mesentery Mesenteric cyst Figure 65.16 Mesenteric cyst. (Reproduced with permission from Coffey JC, Lavery I, Sehgal R (eds). Mesenteric principles of gastro- intestinal surgery: basic and applied principles. Boca Raton: CRC Press, 2017: 85–108.)

frequently , with chyle, varying in consistency from watered milk to cream. Occasionally , the cyst attains a large size. More often unilocular than multilocular, a chylolymphatic cyst is almost invariably solitary , although there is an extremely rare variety in which myriads of cysts are found in various regions of the mesentery . A chylolymphatic cyst has a blood supply that is independent from that of the adjacent intestine and, thus, enucleation is possible without the need for resection of the gut. Enterogenous cysts These are believed to be derived either from a diverticulum of the mesenteric border of the intestine that has become sequestrated from the intestinal canal during embryonic life or from a duplication of the intestine (see Chapter 18 enterogenous cyst has a thicker wall than a chylolymphatic cyst and is lined by mucous membrane, which is sometimes ciliated. The content is mucinous and either colourless or yellowish brown as a result of past haemorrhage. The muscle in the wall of an enteric duplication cyst and the bowel with which it is in contact have a common blood supply; consequently , removal of the cyst always entails resection of the related portion of intestine.