Intrahepatic Splenosis in a Chronic Hepatitis C Patient with no History of Splenic Trauma Mimicking Hepatocellular Carcinoma

BACKGROUND Intrahepatic splenosis (IHS) is the autotransplantation of splenic tissue that mostly develops after abdominal injury and is often misdiagnosed as hepatocellular carcinoma (HCC) because of similarities in radiological features. We had an opportunity to treat an extremely rare case of intrahepatic splenosis, which were found in a patient without any history of splenic injury. To the best of our knowledge, this is the first such case report in the world. CASE REPORT A 58-year-old man with chronic hepatitis C was referred to our hospital for further examination of liver function abnormality. Abdominal ultrasonography incidentally revealed a low echoic tumor in the posterior segment of the liver, with high echoic capsule, which is possibly different from tumor capsule of HCC, known as halo. Abdominal contrast-enhanced computed tomography and gadoxetic acid-enhanced magnetic resonance imaging showed that the tumor had an inhomogeneous enhancement in the arterial phase and diminished enhancement in the equilibrium phase, diagnosed as HCC. The patient underwent right lateral segmentectomy of the liver, and histopathological study confirmed a diagnosis of intrahepatic splenosis. CONCLUSIONS This case presents a new understanding of IHS in a patient without any splenic injury. We also focused on the differences in echo patterns of the tumor capsule between HCC and IHS, which can be used to efficiently diagnose IHS.