MON-497 A Case of Primary Hepatocellular carcinoma with a 12cm Contralateral Indeterminate Left Adrenal mass

Abstract Disclosure: F. El Sayed: None. S. Athimulam: None. Background: Adrenal incidentalomas are found in 5-7% of the population. However, management of these masses can be challenging, especially when they present with indeterminate characteristics on imaging. The differential diagnosis of an indeterminate adrenal mass includes benign lipid poor adenoma, primary adrenal cortical carcinoma (ACC), metastases, pheochromocytoma or other adrenal malignancies. We describe a case of primary hepatocellular carcinoma with a 12 cm contralateral left indeterminate mass and discuss the diagnostic evaluation and management. Case Description: A 71-year-old male with a medical history of compensated Hepatitis C cirrhosis on Epclusa/Ribavirin was undergoing computed tomography (CT) of chest due to a smoking history and known pulmonary nodules. Incidental liver lesions were found and subsequent CT abdomen revealed multiple hepatic lesions (2-4cm) and an incidental heterogenous 12 cm left adrenal mass (unenhanced Hounsfield unit: 30-40). Biopsy of hepatic lesions confirmed diagnosis of well-differentiated hepatocellular carcinoma (HCC). Given the size of the indeterminate left adrenal mass and contralateral location to the liver, primary adrenal cortical carcinoma (ACC) was considered a possible diagnosis, versus metastatic hepatocellular carcinoma.Biochemical testing ruled out aldosterone, cortisol or catecholamine excess. Serum steroid precursors (11-deoxycortisol, 17- hydroxyprogesterone, 17-hydroxypregnenolone and Pregnenolone) were within normal range, suggesting primary ACC is less likely. With the known diagnosis of HCC as an extra-adrenal malignancy, an adrenal biopsy was performed and metastatic HCC was confirmed. Following systemic chemotherapy, the adrenal mass regressed to approximately 4 cm on recent follow up imaging. Discussion: The case highlights the complexity of managing an indeterminate adrenal mass. A stepwise diagnostic approach is crucial to differentiate between benign and malignant causes. Hepatocellular carcinoma is one of the top causes of cancer-related deaths in the world with a rising incidence in the United States over the last several decades. Extra-hepatic metastases are found in 10-15% of patients at time of diagnosis, with the most common locations being the lungs, intra-abdominal lymph nodes and bone. Metastases to the adrenal glands are uncommon, representing 10% of all metastases, especially contralateral metachronous adrenal metastasis such as in this case is rare. Serum steroid precursors can be utilized to differential primary adrenal cortical carcinoma versus other adrenal malignancies or metastases. Adrenal biopsy can be considered in select cases of indeterminate adrenal masses with known history of extra-adrenal malignancy, but pheochromocytoma must be ruled out prior. Presentation: Monday, July 14, 2025