Left renal mass presenting uncommon pattern of extension in a patient with intestinal malrotation

A 41-year-old man who had intestinal malrotation was presented with left renal tumor. The tumor extended venous thrombus up to hepatic portion and showed invasion in vessels and lymph nodes of mesocolon, which extended to porta hepatis. Needle biopsy of the renal tumor showed glandular adenocarcinoma. While colon cancer metastasis was possible, adenocarcinoma or glandular differentiation of urothelial carcinoma of the renal pelvis was also likely. The disease progressed rapidly and the patient died in a few months after the initial hospital visit. The very uncommon pattern of disease progression in this case was considered to be associated with intestinal malrotation, which is characterized by unfixed short mesenterium, abnormal alignment of mid- and hind-guts, and the lack of normal anatomical structures between peritoneum and retroperitoneum including the ligament of Treiz. This case provides an important implication of intestinal malrotation in disease progression, which may affect clinical decision-making in the extent of surgical resection including lymph node dissection.