De Novo Kaposi Sarcoma in an HIV-Negative Liver Transplant Recipient With Ulcerative Colitis and Primary Sclerosing Cholangitis.

De novo or viral reactivation cancers are a major cause of morbidity and mortality in the solid organ transplant (SOT) population. Primary sclerosing cholangitis (PSC) is an aggressive disease which can lead to cholestatic liver damage and cirrhosis. PSC often cooccurs with inflammatory bowel disease (IBD). Here, we describe the case of a 28-year-old male with PSC along with poorly controlled IBD who underwent a liver transplant and developed colonic Kaposi sarcoma (KS). Our case highlights the importance of adequate pretransplant screening for endemic viruses, high clinical suspicion for KS in the setting of difficult-to-control colitis, and early multidisciplinary involvement.