Imaging features of hepatic sarcomatous carcinoma on computed tomography and gadoxetic acid-enhanced magnetic resonance imaging.

PURPOSE: To determine the imaging features of hepatic sarcomatous carcinoma including sarcomatous intrahepatic cholangiocarcinoma (S-ICC) and sarcomatous hepatocellular carcinoma (S-HCC) on computed tomography (CT) and gadoxetic acid-enhanced magnetic resonance imaging (MRI).

MATERIALS AND METHODS: Twenty-four patients with pathologically confirmed S-ICCs (n = 13), S-HCCs (n = 7), sarcomatous carcinoma (n = 2), carcinosarcoma (n = 1), and sarcomatous combined HCC-CC (n = 1) (size range 2.1-23 cm, mean 8.3 cm) underwent gadoxetic acid-enhanced MRI (n = 20) and/or dynamic CT (N = 24). Underlying chronic hepatitis or cirrhosis was found in 17 patients. Two reviewers evaluated morphology, signal intensity, and enhancement features of tumors based on a consensus.

RESULTS: Lobulated contour was observed in 15 tumors (62.5%); the rest were round or oval masses. During dynamic imaging, S-ICCs showed poor enhancement (n = 10 on CT; n = 7 on MRI) or initial thin-rim enhancement with/without progressive enhancement (n = 3 on CT; n = 6 on MRI). S-HCCs and the other four tumors showed a thin or thick enhancement pattern on both CT and MRI. T2 bright signal intensity similar to fluid was found in 10 tumors. Target appearance on hepatobiliary phase and diffusion-weighted imaging was seen in two S-ICCs and two S-HCCs. Of 18 surgically resected tumors, 17 showed vascular invasion and/or thrombosis in histology and 12 in CT and MRI. Ten tumors were accompanied by intrahepatic metastasis or tumor seeding and 19 patients had recurrence or progression of tumors during follow-up.

CONCLUSION: Hepatic sarcomatous carcinoma including S-HCC and S-ICC generally presents minimal rim-like arterial enhancement or extreme hypovascularity on CT and gadoxetic acid-enhanced MRI with a high frequency of T2 bright area due to extensive necrosis and vascular invasion.