S3367 Concurrent Primary Sclerosing Cholangitis and Acute Promyelocytic Leukemia: A Rare Case Report

Introduction: Primary sclerosing cholangitis (PSC) is a progressive inflammatory disease that affects the biliary tree, leading to fibrosis, bile duct strictures, and ultimately hepatic fibrosis. Acute promyelocytic leukemia (APL) is a rare subtype of acute myelogenous leukemia that typically presents with fatigue, weakness, and bleeding. To the best of our knowledge, we present the first reported case of the simultaneous occurrence of these 2 diseases. Case Description/Methods: A 58-year-old man presented with right upper quadrant pain and dark urine. Subsequent magnetic resonance cholangiopancreatography (MRCP) revealed narrowing of the common bile duct, consistent with PSC. One year later, he developed biliary dyskinesia and underwent cholecystectomy. Over the following years, the patient experienced multiple flares and was closely monitored with labs and imaging. Thirteen years after initial diagnosis, surveillance magnetic resonance imaging revealed a new enhancing lesion in the T12 vertebra and L5, suspicious for malignancy. Biopsy of the L5 lesion confirmed myeloid sarcoma, and the patient was started on arsenic trioxide and all-trans retinoic acid (ATO + ATRA). A repeat biopsy 2 months later showed resolution of the lesion. The patient began consolidation therapy, which was complicated by deranged liver enzymes. Labs at the time showed WBC 6.4, Hb 13.3, platelets 152, ALT 82, AST 87, total bilirubin 0.7, and alkaline phosphatase (ALP) 257, prompting temporary discontinuation of treatment. Imaging showed progression of PSC with increased peripheral biliary dilation and multifocal intrahepatic and extrahepatic biliary strictures, along with wall thickening and enhancement, raising concern for ATRA-related PSC progression. Discussion: This case highlights a rare concurrence of PSC and APL, raising the question of a possible association between the 2 diseases. The observed PSC progression following APL diagnosis and treatment presents a clinical dilemma: whether the progression was drug-induced or simply reflects the natural course of PSC.