Sonographic appearances of small organizing hematomas and thrombi mimicking superficial soft tissue tumors.

We retrospectively reviewed 2 cases of organizing hematomas and 2 cases of intravascular organizing thrombi and investigated correlations between sonographic and pathologic findings. In all 4 cases, a well-defined hypoechoic heterogeneous mass with surrounding increased echogenicity was evident in the subcutaneous fat layer. Organizing hematomas and thrombi have sonographic features similar to those of benign-looking soft tissue tumors. These lesions should therefore be considered in the differential diagnosis of superficial soft tissue masses.