Retroperitoneal malignant mesenchymoma: imaging findings in five cases.

BACKGROUND

To describe computed tomographic (CT), magnetic resonance (MR), ultrasonographic (US), and angiographic findings of retroperitoneal malignant mesenchymoma with emphasis on CT findings.

METHODS

Five CT, four US, four angiography, and two MR studies were obtained in five patients with pathologically proven retroperitoneal malignant mesenchymoma.

RESULTS

Tumors were larger than 10 cm (n = 4), well-circumscribed and heterogeneous (n = 4), and with massive intratumorous calcifications (n = 3) on plain CT or US. Tumors showed heterogeneous enhancement on contrast-enhanced CT scans (n = 4) and moderate hypervascularity with heterogeneous staining on angiography (n = 3). Tumors were essentially hypointense on T1-weighted MR images (n = 2) and heterogeneous hyperintense on T2-weighted MR images (n = 2). Plain CT showed a fat-dense structure in a tumor in one patient.

CONCLUSIONS

The radiologic findings of large expansile heterogeneous masses in the retroperitoneum, especially with massive calcifications, were considered to be typical of malignant mesenchymomas.