Nodular fasciitis of the breast: two cases with a review of imaging findings.

Nodular fasciitis of the breast is a rare, benign, proliferative disease characterized by sudden onset and rapid growth. It can clinically and radiologically mimic breast cancer. We present imaging findings from two cases of nodular fasciitis that initially manifested as palpable masses. Sonographically, they appeared as irregular, not-circumscribed hypoechoic nodules. The diagnosis of nodular fasciitis was made by US-guided core needle biopsies. US-guided vacuum-assisted excision was subsequently performed in the first case, while the second resolved via spontaneous regression.