[Imaging manifestations of tumors metastasized in fatty liver]

To evaluate the manifestations of tumors metastasized in fatty liver and the value of various imaging modalities, especially CT.

Nine cases of tumors metastasized in fatty liver were proved by clinical follow-up for 3-13 months. The primary neoplasms were breast carcinoma in 6 cases; ovarian carcinoma, malignant melanoma and colon carcinoma, one case for each. All had CT(19 episodes) and ultrasonography (US, 20 episodes). Four cases had MRI and 2 cases had DSA.

Liver metastatic lesions were missed by US in 2 cases with moderate to marked fatty liver. On CT without contrast administrations, fatty liver was divided into marked, moderate and mild degree according to the density of hepatic parenchyma which was lower than that of the spleen; lower and higher than or equal to that of the intrahepatic blood vessels. Depending on the degree of fat infiltration(FI), the density of the metastatic lesions was high when FI was marked and low when FI was mild. However, when FI was moderate, the density of the metastatic lesions varied, being high, equal or low. On enhanced CT, all of the lesions were enhanced with moderate to marked fatty liver background. Lesions were heterogeneous in 4 cases. On plain CT, metastatic lesions had high-density rim, 2-6 mm in width in 4 cases. In SE sequence of MRI, metastatic lesions were hypointense on T1W and hyperintense on T2W, and moderately hyperintense on opposed-phase.

Tumors metastasized in fatty liver show a broad spectrum of image manifestations. They are related to the degree of fat infiltration. On plain CT, isodense lesions are easily escaped detection when moderate degree of fatty liver is present. Contrast administrations is mandatory. Liver metastases is suggested if a lesion is found with hyperattenuating rim on plain CT, or appears heterogeneous after enhancement. MRI is of diagnostic help.