Abstract
Nodular fasciitis, which is benign proliferation of fibroblasts, rarely occurs in the breasts, is thought it has features on imaging similar to breast cancer. A case of nodular fasciitis incidentally found in a patient with bilateral breast cancer is reported.
A 44-year-old woman was referred for an abnormality on breast screening. Ultrasound showed an 18 × 13 mm mass in the left B region, and needle biopsy showed infiltrating ductal carcinoma. Ultrasound also showed a 21 × 11 mm hypoechoic mass with indistinct borders in the right CD region, while MRI showed contiguous non-mass-enhancement segmentally in the right breast. Needle biopsy suggested an intraductal papilloma, but because malignancy could not be excluded, a right incisional biopsy was performed.
Histopathology showed mainly papillary DCIS in the right breast, but there were also an adjacent mass with fibroblast proliferation. Immunohistological stanining confirmed a diagnosis of modular fasciitis.
