Acute myeloid leukemia masquerading as hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is often diagnosed on the basis of high quality imaging without a biopsy in the cirrhotic liver. This is a case of a 64-year-old Caucasian man with no history of liver disease or cirrhosis that presented with fatigue, weight loss, and abdominal distension and was found to have a large, isolated liver mass with arterial enhancement and portal venous washout on triple-phase computed tomography (CT) suspicious for HCC. The patient was initially referred for a surgical evaluation. Meanwhile, he developed fevers, pancytopenia, and worsening back pain, and a subsequent spinal MRI revealed a heterogeneous bone marrow signal suspicious for metastatic disease. A bone marrow biopsy that followed was diffusely necrotic. A core biopsy of the patient's liver mass was then performed and was diagnostic of acute monocytic-monoblastic leukemia. Findings from peripheral flow cytometry and a repeat bone marrow biopsy were also consistent with this diagnosis, and induction chemotherapy with cytarabine and idarubicin was initiated. This case describes a rare presentation of myeloid sarcoma (MS) as an isolated, hypervascular liver mass that mimics HCC in its radiographic appearance. Due to the broad differential for a liver mass, a confirmatory biopsy should routinely be considered prior to surgical intervention.