Mesenchymal Extratesticular Tumors and Tumorlike Conditions: From the Radiologic Pathology Archives.

Both benign and malignant tumors and tumorlike conditions can arise from the nonepididymal extratesticular tissues. Benign tumors are far more common than malignant tumors, with lipoma being the most common lesion found at this site. Several imaging features can help narrow the differential diagnosis of these lesions, including the presence of fat and imaging features suggestive of fibrous tissue. Lesions that contain fat represent lipoma, liposarcoma, or angiomyofibroblastoma (AMF)-like tumor. If enhancing soft tissue is present in conjunction with fat, the differential diagnosis narrows further to just liposarcoma and AMF-like tumor. Lesions that display magnetic resonance imaging characteristics compatible with fibrous tissue are likely to be fibrous pseudotumor. However, many of the lesions in this location have overlapping imaging findings, and surgical excision is most often necessary for accurate diagnosis. The ability to narrow the differential diagnosis with imaging, however, is helpful for the clinician for both treatment planning and patient counseling.