Adrenal rest tumour of the liver

A 58 year old man with chronic hepatitis B and HIV infection underwent a scheduled abdominal ultrasound for liver cancer screening. A focal hypoechoic lesion of 25mm. was discovered in the segment VII of the liver. Liver function tests and tumor markers levels (α-fetoprotein, Carcinoembryonic antigen (CEA), Ca 19.9) were within normal limits. On contrast abdominal computed tomography (CT) the mass was enhanced heterogeneously in the arterial phase with minimal washout in the portal and delayed phases. On superparamagnetic iron oxide-enhanced magnetic resonance imaging (MRI) the lesion appeared to be slightly hypointense on T1 (Fig. 1A), hyperintense on T2 fat suppression and clearly hypervascular in the arterial phase (Fig 1B). Based on the above radiological findings and the clinical history a diagnosis of hepatocellular carcinoma (HCC) was suspected. The patient underwent a subsegmental liver resection and the postoperative recovery was uneventful. At histology the lesion was diagnosed as an adrenal rest tumor based on morphology and immunostaining (staining was positive for cytokeratin, vimentin, alpha-inhibin; negative for polyclonal CEA and Hepatocyte specific antigen 1). The lesion was adjacent to an area of mature adrenal cortex, surrounded by hepatic tissue. (Fig 1C). Adrenal rest tumor is very rare in the liver and it is supposed to originate from ectopic adrenocortical tissue. Radiologically, adrenal rest tumor shares many features with HCC.(1) Presence of fat components and hypervascularity are suggestive for the diagnosis especially for lesions located beneath the posterior capsule of the right lobe.