S3245 Kaposi Sarcoma of the Ampulla of Vater and AIDS Cholangiopathy: A Rare Biliary Presentation

Introduction: Kaposi Sarcoma (KS) is a low-grade angioproliferative tumor of vascular endothelium, seen in HIV patients, especially with CD4 counts <100. While gastrointestinal (GI) involvement is common among extracutaneous sites, biliary tract involvement is exceedingly rare and presents diagnostic and therapeutic challenges. Case Description/Methods: We report a 25-year-old African American man with HIV (not on highly active retroviral therapy), complicated by cutaneous KS and oropharyngeal candidiasis. He presented with 2 months of diarrhea, weight loss, and anorexia. Labs revealed a cholestatic liver panel: ALP 1883 U/L, AST 235 U/L, ALT 198 U/L, total bilirubin 4.5 mg/dL. CD4 count was 106 with HIV RNA of 2024 copies/mL. He also had cytomegalovirus (CMV) viremia. Imaging with magnetic resonance cholangiopancreatography (MRCP) revealed small liver lesions suspicious for hepatic KS, irregular bile and pancreatic ducts, and an ampullary stricture consistent with type 4 AIDS cholangiopathy. HIDA scan showed cholestasis. Endoscopic retrograde cholangiopancreatography (ERCP) identified a large, vascular ampullary mass; biopsy confirmed KS. Due to its vascular nature, biliary stenting was unsuccessful, and endoscopic ultrasound-guided choledochoduodenostomy was considered. However, his functional decline precluded intervention, and he passed away shortly thereafter. Discussion: KS manifests in 4 forms: classic, endemic, epidemic (AIDS-related), and iatrogenic. GI involvement occurs in up to 50% of AIDS-related KS, often without symptoms. Biliary obstruction from KS is rare but must be considered in patients with cutaneous KS and cholestatic symptoms. AIDS cholangiopathy, frequently due to CMV or cryptosporidium, may co-exist and presents in 4 patterns: papillary stenosis, sclerosing cholangitis, combined disease, and extrahepatic strictures. Our patient had type 4 cholangiopathy likely due to CMV, KS, or both. MRCP helps identify characteristic features, and ERCP with sphincterotomy can offer relief in papillary stenosis. This case highlights a rare presentation of KS of the ampulla of Vater in the setting of AIDS cholangiopathy, underscoring the need for high clinical suspicion in immunocompromised patients with cholestatic liver injury and abdominal symptoms.