An unusual pelvic cyst found at laparoscopic hernia repair.

To cite: Sarantitis I, Weerasinghe C, Varia H, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2015210175 DESCRIPTION The finding of unusual contents within hernias merits publication so as to raise surgeons’ awareness of the structures that could be encountered during hernia repair. 2 We describe a case of a 66-year-old man who underwent elective transabdominal preperitoneal bilateral inguinal hernia repair. At laparoscopy, a large cystic structure was seen arising from the pelvis (figure 1). The hernias were repaired and the patient was informed of the abdominal finding before being discharged home later the same day. The cystic structure was subsequently investigated with a CT scan (figure 2) and MRI (figure 3). The scans showed a benign 16 cm×7.5 cm×6 cm unilocular cyst with calcification in its wall. Aspiration cytology was not performed as this risked puncturing the thin-walled cyst. The radiological diagnosis was of a mesenteric cyst or urogenital cyst. Mesenteric cysts were first described by Benevieni, an Italian anatomist, in 1507. They arise during embryological development from ectopic lymphatic tissue or from incomplete fusion of the leaves of the mesentery. They are very rare, occurring in 1 in 200 000 adults. Malignant transformation is exceptionally rare. Urogenital cysts are equally rare and arise from vestigial remnants of the urogenital apparatus. Malignant change is also exceptionally rare. The management options were to excise the cyst either laparoscopically or by laparotomy to obtain definitive histology, or to adopt a conservative approach with yearly surveillance scans to assess cyst growth or change. In our case, the cyst was completely asymptomatic and radiologically benign, so a conservative approach was adopted. If in future it enlarges and causes pressure symptoms on adjacent structures such as the bladder, excision will be performed.