Abstract
A 46-year-old pre-menopausal woman noticed a right breast lump around July 2010 but left it untreated. In January 2011, experiencing pain in the same region, she consulted us. A 1.5-cm movable hard mass was palpable in the C region of the right breast. Mammography showed no abnormalities, but ultrasonography revealed two vertically aligned hypoechoic masses (4 and 6 mm in diameter), with architectural distortion, in the same breast region. Suspecting breast cancer, we performed a needle biopsy. Pathological findings included marked proliferation of fibroblasts. Three months later, a slight dimple was noted in the same region and we performed a second needle biopsy. Immunological findings suggested fibromatosis. The patient declined surgery, and follow-up ultrasonography in October showed enlargement of the mass. Partial mastectomy was performed. Pathological diagnosis was fibromatosis, a benign neoplastic disease characterized by an invasive proliferation of fibroblasts. Primary mammary fibromatosis is a rare disease and is difficult to differentiate from breast cancer based on clinical findings. First-line treatment is surgical resection, but local recurrence is common, necessitating close follow-up. We report the details of this rare case of mammary fibromatosis and present a literature review.
