patients. With an inadequately understood pathogenesis, acquired vascular malformations should be considered in the differential diagnosis for high-flow lesions found in patients with end-stage systemic manifestations of decompensated liver failure. Case ReportA 53-year-old man with a past medical history of alcoholic liver cirrhosis and portal hypertension presented with confusion, weakness, and ascites. He also presented with left knee pain accompanied by a large palpable mass that had developed along the medial aspect of the left knee. The patient reported he first noted the painful mass at the onset of his liver failure, 8 to 12 months prior to the current presentation. He stated the mass had continued to slowly grow in size. He asserted no history of surgery or prior mass in this location predating the liver failure. He recalled a minor "injury" to the left knee as a child that subsequently resolved with conservative management and no further work-up or intervention. The patient has no family history of an angiomatous syndrome. He had been admitted two months prior for the emergent banding of bleeding esophageal varices. On physical examination, the patient was cachectic and jaundiced. He had multiple sequelae of cirrhosis, including spider angiomata, hepatosplenomegaly, caput medusae, and palmar erythema. Diffuse lower extremity edema and ascites was also noted. A round, pulsatile, partially compressible mass was found on the left anteromedial distal thigh/knee (Figure 1). Laboratory results revealed thrombocytopenia (93 L/uL), hyponatremia AbstractA 53-year-old male with end-stage alcoholic liver cirrhosis and portal hypertension presented with hepatic encephalopathy as well as painful ambulation due to a mass on the medial aspect of his knee. The mass was first noted several months prior, concomitant with his presentation of decompensated liver failure. As a part of the pre-transplant workup, multimodality imaging evaluation of the medial knee mass was completed and revealed a high-flow vascularized soft tissue lesion. Biopsy performed to exclude malignancy confirmed a high-flow vascular malformation, presumably acquired as a sequela of the patient's liver disease. While arteriovenous malformations (AVMs) are common congenital phenomena, this case represents one of the first reported instances of an acquired lower extremity AVM in a patient with end-stage liver disease.