Abstract / Summary
Angiofibroma of soft tissue (AFST) is a rare, benign fibroblastic tumor that is difficult to distinguish from malignancies based on radiological and pathological findings. While several reports have described the clinicopathological findings of AFST, there remains little information on its radiological features and imaging characteristics. We encountered five new patients with AFST (three men and two women) and report their clinicopathological and radiological findings herein. Their ages ranged from 32 to 69 years (median: 53 years; mean: 52 years). The tumors of four of the patients were in the lower limbs while that of the fifth was in the upper limb; their sizes ranged from 3 to 11 cm (mean: 6.8 cm). None of the five patients had tumor-related symptoms. Magnetic resonance imaging (MRI) revealed a bifurcated morphology with relatively clear margins in all the patients, with isointensity on T1-weighted imaging, hyperintensity on T2-weighted imaging, and marked enhancement after gadolinium administration. None of the subjects showed evidence of invasion into surrounding tissues. The differential diagnosis included a malignant soft tissue tumor with myxoid components such as a low-grade myxofibrosarcoma and myxoid liposarcoma. In four patients, a definitive diagnosis of AFST was achieved following the detection of NCOA2 gene rearrangements, whereas the fifth was diagnosed based on histological findings. Four patients underwent marginal resection and have experienced no local recurrence or metastasis, while one remained under careful observation in lieu of surgery because of his poor general condition. Although AFST is a benign tumor, it can mimic a malignant tumor on radiological and pathological findings; therefore, we recommend caution during the differential diagnosis. If MRI reveals a myxoid, lobulated tumor with no apparent invasion of the surrounding tissue and strong contrast enhancement, AFST ought to be considered.