Challenging case with an incidental colonic finding in the context of characterizing the right upper pole solid mass (most likely RCC). 

The diagnosis of chronic ischemic colitis was confirmed by colonoscopy and biopsy, which should characteristic findings of chronic congestion.  This patient has scans performed over a several-year period with similar findings and only mild gastrointestinal symptoms (confirming a chronic presentation). 

What makes this case particularly interesting is the lack of definitive venous drainage of the entire descending colon through rectum (IMV territory). While there are prominent marginal varices, many of these seem to lead nowhere, but there is a smaller venous collateral to the SMV in the left upper quadrant. However, the IMV is simply not identifiable.

In summary, the chronic presentation, vascular distribution, and supporting vascular findings of no IMV can help the reader propose chronic venous congestion as the cause of colitis.