Hepatic Adrenal Rest Tumour (HART) Preoperatively Diagnosed as Hepatocellular Carcinoma in a Patient With Chronic Hepatitis B: Radiological Similarities in Lesions.

Hepatic adrenal rest tumours (HARTs) are rare benign lesions arising from ectopic adrenocortical tissue. Their radiological resemblance to hepatocellular carcinoma (HCC) presents a significant diagnostic challenge. We report a case of HART in a woman in her 60s with chronic hepatitis B (CHB) without cirrhosis who underwent surgical resection following a preoperative diagnosis of HCC. The patient, who was of Filipino descent, was being treated with entecavir and underwent a routine six-monthly HCC surveillance, during which a lesion of concern was identified on ultrasound. Liver synthetic function and serum transaminases were within normal limits, hepatitis B viral load was undetectable, and serum alpha-fetoprotein was normal. MRI demonstrated a 14-mm fat-containing lesion in segment VI according to the Couinaud classification, exhibiting homogeneous arterial phase hyperenhancement and portal venous washout, findings considered radiologically consistent with HCC. Following multidisciplinary review, she underwent laparoscopic hepatectomy. Histopathological examination revealed a well-circumscribed lesion composed of compact nests of uniform cells with regular round nuclei and finely vacuolated clear cytoplasm. Immunohistochemistry demonstrated positivity for inhibin and Melan-A, with negative staining for PAX8, HepPar-1, AE1/AE3, S100, HMB45, synaptophysin, and chromogranin, establishing the diagnosis of HART. This case highlights the difficulty in distinguishing HART from HCC based on imaging alone, particularly in patients with established HCC risk factors. Recognition of HART as a potential differential diagnosis for hypervascular hepatic lesions may support more informed multidisciplinary evaluation and management.