Volvulus of the ascending colon due to failure of zygosis: A case report and review of the literature

INTRODUCTION: Volvulus of the mobile ascending colon is a serious complication of a subtle embryological abnormality that frequently goes unrecognised. There has been renewed interest in the development of the mesentery because of its relevance to the contemporary management of surgical diseases. This case is presented to illustrate the dire consequences of missing this diagnosis and to review the fascinating embryology of the condition as well as its clinical implications. PRESENTATION OF CASE: We report on a 23-year-old male who presented with signs and symptoms of distal small bowel obstruction after a long prior history of intermittent right lower quadrant pain. At laparotomy, a 360-degree counter-clockwise volvulus of the entire right colon was noted as the result of an excessively long ascending mesocolon and unattached hepatic flexure. All gangrenous bowel was resected with primary ileocolic anastomosis performed thereafter. The patient did well post-operatively and was subsequently discharged. DISCUSSION: Interruption of the in-utero events of fixation known as peritoneal zygosis lead to a persistence of the mesocolon in parts of the bowel that ordinarily are retroperitoneal. The events that lead to this anomaly are poorly understood and have been subject to controversy for centuries. New insights have challenged surgical dogma and informed new surgical techniques. Its true incidence is probably underestimated because of its indolent clinical prodrome, and it requires a high index of suspicion. CONCLUSION: Failure of peritoneal zygosis is implicated in a myriad of clinical conditions. Expeditious recognition and intervention in the prodromal period can avert potentially disastrous complications.