OBJECTIVE A 45-year-old woman presented with a lobulated, hypoecho-ic mass in the left lobe of the liver on abdominal sonography. Abdominal CT showed a hyperdense to isodense hepatic mass with a peripheral low-density rim in portal venous phase images. Abdominal MM showed a hypointense mass on Tl- and T2-weighted images. The peripheral rim of the mass was Tl hypointense and T2 hyperintense. On dynamic series, the mass showed marked enhancement in the arterial phase and subsequent progressive washout in the delayed phase. The peripheral rim exhibited delayed enhancement. The final pathologic diagnosis was hepatic actinomycosis.
CONCLUSION Hepatic actinomycosis is a rare granulomatous disorder. Imaging findings of hepatic actinomycosis are various and may mimic those of neoplasms. Abdominal MRI offers the benefit of tissue contrast that is superior to that of CT in the differentiation of inflammatory pseudotumor from other solitary hepatic neoplasms. Fine-needle biopsy or surgery is necessary for definite diagnosis and management.