A Case of Hepatic Adenoma With Imaging Suggestive of Fibrolamellar Hepatocellular Carcinoma

Abstract

Introduction: Hepatic (Hepatocellular) adenomas are uncommon benign liver tumors that occur more in women of child-bearing age and are strongly associated with glycogen storage diseases, and intake of OCPs or anabolic steroids. Here, we report the case of a woman with a large hepatic adenoma and imaging findings mimicking fibrolamellar hepatocellular carcinoma. Case report: A 37 year-old female with a history of Protein C deficiency, and chronic lower extremity lymphedema presented with several weeks of intermittent right upper quadrant pain, described as dull and radiating to her back. Patient denied any history of liver disease, alcohol abuse or OCPs use. Clinical examination showed hepatomegaly with liver edge palpated at the level of umbilicus. Initial work up included complete blood count, electrolytes, urine analysis and liver function tests which were all within normal limits. Abdominal ultrasound showed a large liver mass. An MRI liver with gadolinium contrast showed the same mass with nonspecific imaging appearance. Triple-phase contrasted CT showed a heterogeneously arterial hyper-enhancing mass with portal venous and delayed washout centered within segments 4, 5 and 8 (images 1 and 2). Alpha fetoprotein was within the normal range, and viral hepatitis panel was negative. Patient underwent a right trisegmentectomy with Roux-en-Y hepaticojejunostomy. Discussion: Hepatic adenoma is a benign liver tumor seen predominantly in young women, with a small risk of malignant transformation. It is typically asymptomatic but can present with pain or a palpable mass, or with spontaneous rupture and hemorrhage. Long-term use of estrogen or androgens is the main risk factor for hepatic adenoma, and the yearly incidence varies from 1 per million in women not on OCPs to 3.4 per 100000 in those taking OCPs. The diagnosis is made based upon the combination of the clinical setting and imaging, or pathology. Adenomas typically show initial peripheral enhancement and subsequent centripetal enhancement on contrasted CT, but in this case CT findings described above in combination with patient's age and lack of preexisting liver disease suggested possible fibrolamellar hepatocellular carcinoma, a rare primary malignant liver tumor affecting young patients with a possible female predominance. In this case, given the lesion size and associated symptoms, surgery was performed, with pathology confirming the diagnosis of hepatic adenoma.2373_A Figure 1 No Caption available.2373_B Figure 2 No Caption available.