a 43-year - old man visited the emergency room with epigastric pain . according to the patient , he had no significant medical or surgical history , except for hospitalization 20 years ago due to similar abdominal pain that resolved with conservative treatment . the patient 's vital signs were stable and mild tenderness was noted on the epigastric area . the abdominal ct scan was performed with using a 16 row detector ct ( sensation16 , siemens , erlangen , germany ) at the portal phase after administering intravenous iodinated contrast agent ( ultravist 300 , bayer schering pharma , berlin , germany ) . a well - demarcated lesion approximately 15106 cm in size with homogeneous fluid attenuation was noted in the pelvic cavity . the lesion was located within the rectovesical pouch , and it mimicked peritoneal inclusion cysts or loculated ascites . twenty days after the first visit to our hospital , he revisited the emergency room with recurred epigastric pain . the blood urea nitrogen and creatinine ( 42.4 and 2.09 mg / dl , respectively ) were slightly more increased than before ( 14.2 and 1.06 mg / dl , respectively ) , but the other laboratory results were normal . on physical examination , there was tenderness and rebound tenderness on the epigastric area , with hyperperistaltic bowel sounds . the plain radiograph suggested a markedly distended inverted u - shaped small bowel loop with an air - fluid level ( fig . a fluid density mass abutting to the small bowel loops was again noted in the pelvic cavity ( fig . 1b ) . a thin fatty layer between the mass and the small bowel suggested that the mass probably originated from the mesentery rather than from the bowel loop . whirling of the mesenteric vessels and small bowels around the superior mesenteric artery was disclosed on the axial and coronal reformation images ( fig . a dilated small bowel was seen tapering with a beaked appearance at the center of the whirling and this continued to the collapsed small bowel that abutted the cystic mass in the pelvic cavity . a markedly distended small bowel loop proximal to the collapsed segment was found , and this corresponded with the distended bowel loop seen on the plain radiographs . all the findings were suggestive of volvulus of the small bowel with closed loop obstruction , and we presumed that the cystic mesenteric mass was the cause of the volvulus . diagnostic laparotomy was performed and a large cystic mass arising from the small bowel mesentery at 60 cm distance from the treitz ligament was found ( fig . there was no communication between the cystic mass and the lumen of the small bowel . we observed torsion of this cystic mass that caused volvulus of the connecting mesentery and 55 cm of the small bowel , and this eventually resulted in closed loop obstruction of the small bowel . there was stricture and luminal narrowing at the twisted small bowel , so segmental resection and end - to - end anastomosis were performed . there are two distinct categories of small bowel volvulus : the first is the primary type that 's defined as torsion of a segment of the small bowel mesentery without evidence of any predisposing anatomical abnormalities , and the secondary type is precipitated by underlying anatomical abnormalities , including postoperative adhesion , malrotation , congenital bands , intussusception , colostomy , fistula , tumors and meckel 's diverticulum ( 3 ) . although rare , a large mesenteric mass can rotate and be accompanied by volvulus of the connected mesentery and small bowel , and eventually closed loop obstruction of the involved bowel loop occurs ( 4 - 6 ) . in our case , small bowel volvulus and a closed loop obstruction induced by the rotation of the mesenteric lymphangioma brought the patient back to the emergency room again . at the first emergency room visit , the patient 's abdominal pain was associated with incomplete small bowel volvulus and the second time his symptoms were induced by complete small bowel volvulus , which made him return to the emergency room . ischemic damage caused by repeated episodes of torsion by the mass was probably responsible for the stricture of the involved small bowel ( 7 ) . lymphangioma is a congenital malformation of the lymphatic vessels and this is thought to usually be a pediatric disease . approximately 95% of lymphangiomas are found in the neck and axilla and the other 5% occur in the mediastinum and abdominal cavity , including the mesentery , retroperitoneum and bones ( 3 ) . the most common symptom of mesenteric lymphangioma is a palpable abdominal mass and abdominal distension ( 1 ) . intestinal obstruction related to the mesenteric cysts can be induced by compression or traction by the mass ( 6 , 8) . the attenuation of the fluid varies according to the internal contents , from that of fluid to that of fat ( 1 ) . characteristic thin walls and septa also can be seen on a ct scan ( 3 ) . mdct with thin slice multiplanar reformation is helpful to not only diagnosis the lesion , but also to assess the complications such as volvulus , as was noted in our case . the first is that the flaccid and mobile characteristics of a mesenteric lymphangioma cause it to rotate , and this induces small bowel volvulus . the second is that longstanding or intermittent volvulus causes lymphatic obstruction , and this forms lymphatic cysts as a result . the latter case generally forms a unilocular cystic mass without internal septa ( 9 , 10 ) . in our case , a multilocular mesenteric cyst was the primary pathology that secondarily caused volvulus of the small bowel . the differential diagnosis of a cystic lesion in the pelvic cavity includes reactive ascites , duplication cysts arising from the bowel or bladder , and cystic lesions of the seminal vesicle . in our case , the lesion was present before complete small bowel volvulus and the resultant closed loop obstruction , and this had a relatively unchanged morphology during 20 days . also , the shape of the margin between the lesion and the adjacent small bowel was convex and lobulated . these findings were suggestive of a cystic mass rather than loculated ascites . in our case , the thin fatty layer between the mass and the small bowel loops told us that the mass did not directly arise from the bowel loops . furthermore , after the volvulus of a mass and small intestine progresses , the intrusion of a part of the mass into the whirling of the bowel and mesentery reflects the flaccid characteristics of lymphangioma . in adults , mesenteric lymphangioma should be included to the list of rare etiologies of small bowel volvulus . radiologic evaluation , and especially with mdct , is critical for making the correct preoperative diagnosis and treatment plan .
mesenteric lymphangiomas are rare abdominal masses that are seldom associated with small bowel volvulus , and especially in adult patients . 
 we report here on an unusual case of small bowel volvulus that was induced by a mesenteric lymphangioma in a 43-year - old man who suffered from repeated bouts of abdominal pain . at multidetector ct , we noticed whirling of the cystic mesenteric mass and the adjacent small bowel around the superior mesenteric artery . 
 small bowel volvulus induced by the rotation of the mesenteric lymphangioma was found on exploratory laparotomy . 
 lymphangioma should be considered as a rare cause of small bowel volvulus in adult patients .