Abstract
The patient was a 34-year-old man, after bone marrow transplantation for myelodysplastic syndrome, who had underwent splenectomy for idiopathic thrombocytopenic purpura. He then developed right portal vein and splenic vein thrombosis. During follow-up, abdominal computed tomography (CT) showed a hepatic tumor in segment 2 of the liver that had grown from 10 mm to 15 mm in 4 months. The tumor showed a high-intensity area in the arterial and portal phases, and Gd-EOB-DTPA-enhanced MRI showed a low-intensity area with a ring-shaped high-intensity area in the hepatobiliary phase. Focal nodular hyperplasia (FNH) was suspected, but the possibility of hepatocellular carcinoma (HCC) could not be ruled out. Therefore, laparoscopic partial hepatectomy (S2) was performed.
Histological assessment showed the central scar and hepatocytes with slight nuclear atypia that constituted the tumor masses. Immunohistological assessment showed a bile ductule that was positive for CK7 and abnormal muscular vessels that were positive for h-caldesmon. Based on these findings, FNH was diagnosed. Although rapid growth of FNH is rare, the doubling time in the present case was equivalent to that of moderately differentiated HCC. The change in hepatic blood flow that originated from postsplenectomy portal vein thrombosis might have been related to the onset and rapid growth of the FNH.
