Aggressive angiomyxomas: A comprehensive imaging review with clinical and histopathologic correlation

OBJECTIVE. Aggressive angiomyxomas are rare infiltrative mesenchymal neoplasms that commonly recur locally. The purpose of this study was to conduct a retrospective review of imaging findings of aggressive angiomyxomas with clinicopathologic correlation in 16 patients. MATERIALS AND METHODS. CT and MRI studies and clinical data of 16 patients with histopathologic evidence of aggressive angiomyxoma who had been referred to our institutions from January 2002 through January 2012 were retrospectively reviewed. The tumors were evaluated with respect to location, morphology, attenuation or signal intensity, and enhancement characteristics. RESULTS. The most common location was the pelvis and perineum with the mass on either side of the pelvic diaphragm (12/16, 75%). The characteristic "laminated" appearance was seen in 10 of 12 patients on MRI. Aggressive angiomyxomas showed only mild diffusion restriction and mild ¹⁸F-FDG avidity in both of the two patients who underwent DWI and PET/CT, in keeping with histologic low-mitotic activity. Imaging features, such as collateral vessels and fingerlike growth pattern, were seen in seven of 16 (44%) aggressive angiomyxomas. Internal cystic degeneration was seen in three of 16 (19%) aggressive angiomyxomas. CONCLUSION. The finding of a large multicompartmental tumor with a characteristic internal laminated morphology or extension on either side of the pelvic diaphragm should alert the radiologist to the possible diagnosis of aggressive angiomyxoma. Imaging features, such as large peripheral vessels and cystic degeneration are less common, but presence of these features in the background of laminated morphology should not deter the radiologist from suggesting a diagnosis of aggressive angiomyxoma.