S3554 Paraneoplastic Biliary Stricture Presenting as Cholestatic Liver Injury: A Difficult Diagnostic Distinction

Introduction: Paraneoplastic syndromes can present as 1 of many potential causes for biliary stricture and cholestasis. Awareness of unusual etiologies is vital to avoid misdiagnosis and guide treatment. Case Description/Methods: We report a case of 42-year-old woman with history of uterine carcinosarcoma treated 3 years prior with TAH-BSO and chemotherapy. After 2 years in remission she developed new abdominal pain. A computed tomography scan found an abdominal wall mass with peritoneal nodules. Biopsy showed peritoneal carcinomatosis. One month later she presented with worsened pain and elevated liver function tests (LFTs): total bilirubin 5.1(direct 4.0), AST/ALT 540/400, and ALP 400. Extensive liver disease workup was negative with the exception of ANA titer 1:320 (speckled pattern). US liver with doppler showed trace intrahepatic biliary dilation without portal vein occlusion. Magnetic resonance cholangiopancreatography (MRCP) showed no biliary ductal abnormality or obstruction. AST/ALT and bilirubin remained steady but ALP rose to 1100. Interventional radiology liver biopsy showed moderate cholestasis and lobular non-necrotizing granulomas with mild steatosis. There were no features of steatohepatitis, malignancy, or suggestive of acute bile duct obstruction, ductopenia, or chronic biliary tract disease. The differential included drug-induced liver injury vs paraneoplastic syndrome. Medication review showed chronic atorvastatin and duloxetine use but 3 months prior she started bupropion. These were stopped on arrival. She was discharged with diagnosis of DILI after LFTs began to downtrend. She returned after 1 month with continued pain and rise in LFTs. These were monitored with AST/ALT fluctuating around 100-400, bilirubin around 8-15, and ALP climbing to a peak of 1900. Endoscopic ultrasound showed normal bile ducts and liver parenchyma with FNA liver biopsy showing similar histological findings. Repeat MRCP showed worsening intrahepatic biliary dilation with abrupt cutoff in the central intrahepatic ducts and normal common bile duct (CBD). Endoscopic retrograde cholangiopancreatography (ERCP) was done but we were unable to pass the guidewire beyond a mid CBD stricture. A 3 Fr 5 cm plastic stent was placed into the CBD with flow of bile. Following stent placement patient was discharged after LFTs downtrended and on follow up her LFTs normalized. Discussion: While undergoing a complex diagnostic course, ultimately the patient’s LFTs improved following stenting of her paraneoplastic biliary stricture. This case highlights the difficulty in diagnosis and the importance of consideration of paraneoplastic biliary strictures in patients with underlying malignancy and unexplained biliary abnormalities.