Mesenteric cysts are rare intra-abdominal pathology with prevalence 1:100,000 in adults and 1:20,000 in children.[1] Mesenteric cysts are difficult to diagnose, and usually asymptomatic except when complicated. Only rarely do they present with acute intestinal obstruction.[2] We present two cases with small bowel obstruction due to mesenteric cyst. Both needed bowel resection with primary end-to-end anastomosis.

Case 1

A 24-year-old female presented with history of vomiting, constipation and abdominal distension of five days duration. On examination, the abdomen was uniformly distended and visible loops of small bowel were present, with no tenderness and no palpable mass. Per rectal examination revealed an empty non-dilated rectum. Ryle’s tube aspiration was feculent. Abdominal radiographs showed evidence of multiple air-fluid levels with dilated jejunal and ileal loops and no gas within the colon. There was no free gas under the diaphragm. A diagnosis of small bowel obstruction was made while its cause could not be speculated.

Exploratory laparotomy with midline incision was undertaken where jejunal and ileal loop were found to be grossly distended. A single, ruptured mesenteric cyst of 13 × 10 × 7 cm arising from the distal ileum was found. A clockwise torsion of the cyst, leading to a constrictive narrowing of the adjacent small bowel loop was noted. The cyst was closely related to bowel wall with mesenteric blood vessels crossing over it, and separation was difficult (Figure 1). Fortunately the bowel was healthy. Hence the cyst, the mesentery containing it and the adjacent ileum were resected and end-to-end anastomosis was performed. Postoperative recovery was uneventful. Histology was consistent with mesenteric cyst.

Case 2

A 44-year-old male came with complaints of vomiting and abdominal distension of four days duration. The vomitus was bilious with feculent smell and pain was episodic, sharp, nonradiating, and right-sided. The patient gave a history of an asymptomatic moving lump in abdomen since 2 years. The abdomen was diffusely distended with no tenderness and no palpable mass.. Abdominal radiographs showed evidence of multiple air-fluid levels with dilated ileal loops and no gas within the colon without free gas under the diaphragm. The diagnosis of small bowel obstruction was made and the cause could not be ascertained.

During exploratory laparotomy with midline incision, ileal loops were found to be grossly distended. There was single twisted, mesenteric cyst of 10 × 15 × 8 cm arising from the distal ileum found; leading to a constrictive narrowing of the adjacent small bowel loops. The cyst was closely related to bowel wall with inflamed and oedematous bowel loops in pool of slough (Figure 2). Thus the cyst, the mesentery containing it and the adjacent ileum were resected and end-to-end anastomosis was performed. Postoperative period was uneventful. Histology confirmed a mesenteric cyst

Discussion

Mesenteric cysts are one of the rarest abdominal pathology.[1,2] Italian anatomist Benevenni first described this entity in 1507 while performing an autopsy on an 8 years old boy.[3] Mesenteric cysts are believed to be a manifestation of continued growth of congenitally misplaced lymphatic tissue. The initiating event is suspected to be a failure of the mesentery to fuse during development. Trauma and inflammation are additional factors implicated in their formation.[2,4] Mesenteric cysts have been reported from the duodenal to the rectal mesentery but are most commonly located in the ileal mesentery.[2] The cyst in our patient was located in the mesentery of the ileum. Their histopathological classification is based on the type of cells present in the inner cyst wall layer. Accordingly mesenteric cysts can be lymphatic, mesothelial, enteric, or urogenital in origin, or derivatives of nonpancreatic pseudocysts. Fortunately they usually behave as benign tumors, with malignancy accounting for only 3% of the cases, arising gradually or de novo.[2]

Patients are usually asymptomatic except when cyst gets complicated. Symptoms are extremely variable and are related to the size and position of the cyst, with no pathognomonic signs in the uncomplicated patients.[5] Mesenteric cysts may cause abdominal distension or pain. They may also present with acute symptoms secondary to complications such as obstruction (volvulus, extrinsic compression or entrapment in pelvis), rupture, and haemorrhage into cyst, infection or abscess formation.[2] Infected mesenteric cyst and/or perforation are very rare complications of a very unusual lesion. Intestinal obstruction is a frequent complication and is usually produced by compression of the adjacent intestine[6] as noted in our cases. The differential diagnosis should include mesenteric cyst when the patient presents with a history of multiple episodes of partial small-bowel obstruction or with an asymptomatic abdominal mass.[4]

A variety of diagnostic modalities can be used to confirm the presence of a mesenteric cyst, but ultrasonography (USG) and computed tomography (CT) are the best preoperative diagnostic tools.[4] The treatment of choice is an urgent laparotomy and complete cyst enucleation.[6] Surgical treatment is recommended on the basis of histopathologic malignant features and other complications, including infection of the cyst, obstruction of adjacent bowel segment, and volvulus.[5] But when there is a doubt of compromised bowel or its vasculature after excision of cyst alone, segmental resection of bowel with mesentery and cyst is preferred,[2,4] as was done in our cases. Simple aspiration of cyst is not recommended as it may recur. The prognosis of patients operated in a timely manner is good with no perioperative mortality and a very low morbidity and recurrence rate.[7]

Acknowledgments

We thank all staff members of Department of Surgery, Jawaharlal Nehru Medical College, DMIMSU, Sawangi (Meghe), Wardha

References