[Poorly differentiated hepatocellular carcinoma with sarcomatous change causing intraparenchymal rupture and rapid...

The patient was a 73-year-old man who had undergone surgery for gastric cancer in January 2020 and was subsequently attending an outpatient clinic. In May, he presented with right upper abdominal pain. A computed tomography (CT) scan revealed an intraparenchymal rupture of a pseudoaneurysm in a segmental branch of the hepatic artery, and a transcatheter arterial embolization was performed. A follow-up CT scan in August showed a tumor in the same area. Retrospectively, the pseudoaneurysm in the segmental branch of the hepatic artery, which had experienced intraparenchymal rupture, was identified as the feeding artery for the tumor. In October, a right hepatic lobectomy was performed. Pathological examination confirmed a diagnosis of poorly differentiated hepatocellular carcinoma (HCC). This case highlights a rare instance of HCC causing intraparenchymal rupture.