Fibromatosis: Not Always a Spiculated Mass!

Extract

A 54-year-old woman presented with a palpable abnormality in the left breast. The patient had a screening MRI at an external facility 18 months prior, which identified nonmass enhancement in the same location as her current palpable mass, prompting additional diagnostic evaluation with mammogram and US. An US-guided biopsy was then performed with pathologic analysis demonstrating healthy fibroglandular tissue, deemed concordant at the outside facility.

The left diagnostic mammogram performed at our facility demonstrates a 5.0-cm oval mass with both circumscribed and indistinct margins in the upper inner breast, corresponding to the patient-indicated area of palpable abnormality (Figure 1). The mass was seen at site of previously biopsied focal asymmetry at the external facility, although it had significantly increased in size and density. A tissue marker from the previous biopsy was identified at the margin of the mass.

Left breast US showed a heterogeneous mass with alternating areas of hypoechoic and hyperechoic tissue and indistinct margins in the upper inner left breast (Figure 2), corresponding to the mammographic finding.