Case study of inferior adrenal artery as an extrahepatic collateral arterial supply to hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is primarily supplied by hepatic arteries, but extrahepatic collaterals can occur. We present a rare case of HCC receiving blood supply from the right inferior adrenal artery (IAA). A 60-year-old male with HCC underwent multiple rounds of transarterial chemoembolization (TACE) for downstaging. After initial treatments, CT imaging revealed residual disease. Angiography demonstrated tumor supply from the right IAA. TACE was successfully performed via this vessel, leading to significant tumor necrosis confirmed by post-transplant pathology. This case emphasizes the importance of recognizing variant vascular supplies in HCC, especially in patients with prior TACE and tumors in segments VII and VIII. The IAA, while uncommon, should be considered as a possible collateral supply in challenging cases. Awareness of rare extrahepatic collateral supplies, such as the IAA, is crucial for achieving optimal outcomes in TACE procedures for HCC.