Laparoscopic sigmoidectomy for sigmoid colon cancer with left-sided inferior vena cava and persistent descending mesocolon.

Left-sided inferior vena cava (IVC) is a rare congenital malformation, as is persistent descending mesocolon, a developmental anomaly in which the colonic mesentery does not fuse with the dorsal abdominal wall. Although these anomalies are mostly asymptomatic, they should be identified preoperatively to avoid iatrogenic injury. We report a case of sigmoid colon cancer in a patient with both anomalies. The patient was an 80-year-old man whose preoperative computed tomography (CT) scan showed that the IVC ascended vertically along the left side of the abdominal aorta, and the descending colon was at the abdominal midline. Coronal CT was particularly useful for visualizing these anomalies. With this better understanding of the malpositioned anatomy, we successfully performed laparoscopic sigmoidectomy with lymph node dissection. Careful evaluation of preoperative CT imaging based on a clear understanding of such anatomical anomalies is particularly important for performing safe laparoscopic surgery.