Mesenteric cysts.

<b>Introduction:</b> Mesenteric cysts (MCs) are a rare pathology of the abdominal cavity (with an incidence of 1/27.000 to 1/250.000 admissions) and less than 1000 cases have been described in the specialized literature.<b>Aim:</b> To identify the characteristics of clinical manifestations, diagnostics, and treatment of MCs.<b>Materials and methods:</b> Within 2001-2017, 17 consecutive patients with MCs were observed. Ultrasound scan (n = 17), computed tomography (n = 15), and magnetic resonance imaging (n = 1) were used to diagnose MC.<b>Results:</b> The mean age of patients with MCs was 43.4 3.5 years (range from 19 to 67), with a significant predominance of women (n = 14, 82.4%). The main clinical symptoms of MCs included abdominal pain (n = 9, 52.9%), pain + abdominal discomfort (n = 4, 23.5%), abdominal pain + nausea (n = 2, 11.8%), and abdominal discomfort (n = 2, 11.8%). In 13 (76%) cases, a palpable mass was noted in the abdominal cavity. According to imaging studies, the largest size of the MCs was 12.1 1.2 cm (from 5 to 20 cm) and the smallest - 8.6 0.8 cm (from 4 to 15 cm). The density of MC contents by computed tomography data varied from 2 to 26 HU. All patients underwent surgery via laparotomy. MCs were significantly more often located in the mesentery of the large bowel (n = 14, 82.4%) as compared to the small intestine (n = 3, 17.6%). The MCs of the small intestine in all cases were located in the mesentery of the jejunum, whereas in the colon lesions, they were distributed as follows: cecum (n = 1, 7.1%), ascending colon (n = 3, 21.4%), transverse colon (n = 7, 50%), and sigmoid colon (n = 3, 21.4%). Most MCs (n = 16, 94.1%) were enucleated, and only in one case segmental resection of small intestine with MCs was performed. The histopathological examination revealed: simple mesothelial MC - in 8 (47.1%), simple lymphatic MC - in 7 (41.2%), and lymphangioma - in 2 (11.7%) cases.<b>Conclusions:</b> MC is a rare pathology of abdominal organs. The clinical manifestations of MCs are nonspecific, and the final diagnosis becomes apparent only during surgery. In most cases, it is possible to perform MC enucleation without long-term recurrences.