Perivascular Epithelioid Cell Tumor (PEComa) of the Liver Diagnosed by Contrast-enhanced Ultrasonography

Perivascular epithelioid cell (PEC) is a unique cell which expresses both myogenic and melanocytic markers, and forms PEComa. A 36-year-old woman presented with a 35 mm-diameter liver tumor. MRI showed poor fat component in the tumor. Contrast-enhanced ultrasonography using the newly developed enhancing reagent, Sonazoid, clearly demonstrated early-phase enhancement of the tumor and rapid drainage of the reagent to veins, suggesting a PEComa. Lateral segmentectomy of the liver was performed. Histologically, epithelioid tumor cells around the vessels were immunostained with both HMB-45 and α-smooth muscle actin, confirming the diagnosis of PEComa. No recurrence has been found for 18 months following the operation.