Extramedullary hematopoiesis (EMH) in the liver allograft presenting with a mass-like lesion

This is a rare case of extramedullary hematopoiesis (EMH) presenting as a mass-like lesion in liver allograft. Our patient was a 57-year-old woman who had undergone liver transplantation due to hepatic epithelioid hemangioendothelioma. She presented with an ill-defined hypoechoic lesion on ultrasound which showed features of focal EMH on pathologic examinations. While transient intrahepatic hematopoiesis has been reported in liver transplant patients, focal EMH mass lesion is a rarely encountered phenomenon. Therefore, focal EMH may need to be considered as a differential diagnosis when encountering a mass in post liver transplant patients.