S5412 Beware the “Benign” Hepatic Cyst: Mass Effect Causing Portal Vein Thrombosis

Introduction: Simple hepatic cysts are common incidental findings on abdominal imaging and are typically managed expectantly if asymptomatic. However, symptoms can develop due to mass effect, infection, rupture, or hemorrhage of the cyst in which case intervention is warranted. We describe a unique case of a large hepatic cyst causing mass effect with associated intrahepatic portal vein thrombosis (PVT) in an otherwise healthy male. Case Description/Methods: A 77-year-old man with previously asymptomatic simple hepatic cysts presented to his primary care physician with several months of worsening post-prandial right upper quadrant (RUQ) abdominal pain. Ultrasound (US) demonstrated interval enlargement of his cysts without hepatic steatosis, advanced fibrosis, thrombosis, or features of portal hypertension. US-guided aspiration of the largest right lobe cyst successfully removed 1.6 liters of brown fluid; cytology was negative. His pain improved post-procedure; however, the following day he developed worsening RUQ pain prompting emergency department presentation. Contrasted computed tomography demonstrated rapid re-accumulation of the cyst with compression of the right portal vein and acute non-occlusive PVT; he was subsequently admitted. Further drainage was planned with interventional radiology but aborted when intraprocedural US revealed septations. Subsequent contrasted magnetic resonance imaging (MRI) for further definition favored the septations to be sequelae of recent aspiration rather than a biliary cystadenoma. The patient was initiated on apixaban to promote recanalization and prevent further PVT progression. Prior to discharge, surgery was consulted for cyst fenestration of the largest cysts in segment 6 and 7. He underwent an uncomplicated, successful robotic procedure several weeks later in the outpatient setting with full resolution of his RUQ pain. At outpatient hepatology follow-up he was doing well, although on repeat contrasted MRI there was a lack of recanalization of the right intrahepatic portal vein, suggestive of developing chronic thrombosis. His apixaban was continued with planned 6-month total course. Discussion: Portal vein thrombosis is a rare but serious hepatic cyst complication due to mass effect. Multimodal management is necessary when hepatic cysts become symptomatic or recurrent. An acute change in symptoms in patients with a history of hepatic cysts should prompt early contrasted cross-sectional imaging to assess for complications.