Transarterial Radioembolization (TARE) Complicated by a Mycotic Aneurysm and Bleeding: A Case Presentation and Literature Review.

Hepatocellular carcinoma (HCC) is a primary cancer of the liver, typically developing in the setting of chronic liver disease, especially in patients with cirrhosis related to chronic hepatitis B or C virus infections, nonalcoholic steatohepatitis (NASH), or chronic alcohol abuse. HCC is the third leading cause of cancer-related deaths in the world and one of the fastest-growing causes of cancer death in the United States. The reason for this poor prognosis of most HCC patients is the advanced stage at diagnosis. HCC patients are frequently asymptomatic at early stages, and screening even for high-risk individuals is typically lacking. Our case is illustrative of this. A male patient had chronic liver disease from NASH, but was never screened for liver cancer. At presentation, he had a tumor measuring over 6 cm, which was considered unresectable due to its size and the presence of underlying cirrhosis. For patients with limited intrahepatic tumor burden with unresectable tumors, a locoregional approach is normally recommended, as opposed to systemic treatment. The choice of local regional therapies includes local thermal ablation, transarterial chemoembolization (TACE), transarterial radioembolization (TARE), hepatic artery infusional chemotherapy (HAIC), and stereotactic body radiation (SBRT). Both thermal ablation and SBRT work better for smaller tumors that measure less than 3 cm. HAIC is limited to centers with technical expertise. TACE and TARE are the primary options for this condition. Meta-analyses comparing TACE versus TARE suggest TARE provides significantly longer time to progression compared with TACE, with less toxicity. It also entails fewer treatments but at a higher cost. Our patient opted for TARE, which resulted in good tumor regression but was complicated by the development of a liver abscess in the treated area. Liver abscess is a rare complication of TARE. Following embolization, the tumor tissue dies, and in rare cases, this area of necrosis becomes infected, forming an abscess. This infection may be due to bacteria from a compromised biliary tract or the bloodstream. An extremely rare secondary complication of the liver abscess is the development of a mycotic aneurysm in the branch of the hepatic artery surrounded by the liver abscess. The liver abscess in our patient surrounded a branch of the hepatic artery. The infection caused inflammation and weakening of the arterial wall. This damage led to the formation of an aneurysm, an abnormal bulge in the blood vessel, called "mycotic" because it is caused by infection. This is an extremely rare occurrence post TARE. As such, even physicians regularly treating HCC patients are not aware of this possible complication. Such a mycotic aneurysm can rupture with catastrophic consequences.  Percutaneous drainage and prolonged antibiotics are the standard treatment, which our patient received for his liver abscess. Unfortunately, despite this, a mycotic aneurysm formed, which subsequently ruptured, leading to a near-catastrophic event. The purpose of this paper is to alert physicians to this unusual complication from TARE, such that prompt diagnosis and intervention can ensue.