Hepatic adrenal rest tumor mimicking hepatocellular carcinoma

Adrenal rest tumor in liver is a very rare tumor. It originates from an adrenal rest, which is derived from the aberrant adrenocortical tissue. Adrenal rest tumor is an ectopic collection of adrenocortical cells in extra-adrenal sites. This tumor may be hormonally active and manifest endocrine syndromes. But, most tumors are non-functioning and benign. Histologically, hepatic adrenal rest tumors (HARTs) are composed of low columnar or cuboidal clear cells, similar to adrenocortical tumors. At imaging, HART is typically subcapsular tumor, demonstrating macroscopic fat and hypervascularity. Radiologically, adrenal rest tumor shows similar findings with those of hepatocellular carcinoma (HCC), adenoma or other hepatic tumors. Differentiation of HART from angiomyolipoma or HCC may be difficult at both radiologic and histologic analysis. Especially in case of HART without macroscopic fat component, preoperative radiologic diagnosis of adrenal rest tumor is confusing with HCC. So, differential diagnosis should be made with caution. Here is a case of adrenal rest tumor with radiological imaging findings of HCC.