Benign Breast Lesions That Mimic Cancer: Determining Radiologic-Pathologic Concordance

Julia Mario, BA; Shambhavi Venkataraman, MD; Vandana Dialani, MD; Priscilla J. Slanetz MD, MPH


Appl Radiol. 2015;44(9):28-32. 

In This Article


Mammary fibromatosis, also known as desmoid tumor, is a rare, benign tumor of fibroblasts and myofibroblasts.[30,31] Clinically, it presents as a firm, painless, mobile mass, although patients can present with focal pain if the tumor involves the chest wall. Additional physical findings may include skin retraction, dimpling, or nipple retraction, arousing suspicion for breast carcinoma.[30,31] On mammography, fibromatosis typically appears as a spiculated mass whereas on ultrasound it typically presents as a hypoechoic mass with spiculated, irregular or microlobulated margins[30] (Figure 4a). On MRI it usually appears as a mass with low to medium signal intensity on T1-weighted images and variable signal intensity of T2-weighted mages, with benign or Type I kinetics.[32] Chest wall involvement is best evaluated by MRI (Figure 4b). Wide surgical excision is preferred, as these tumors tend to be locally aggressive.[31]

Figure 4.

Spindle cell lesion. (A) A 25-year-old lactating woman presented with a palpable abnormality in her right breast. Ultrasound shows an irregular shadowing hypoechoic mass suspicious for malignancy. Core biopsy revealed spindle cell lesion. Excisional biopsy confirmed fibromatosis. (B) A 53-year-old woman presented with increasing focal pain in the inferior medial left breast. Mammography (not shown), revealed a focal asymmetry that corresponded to an irregular hypoechoic mass extending into an intercostal space on ultrasound (not shown). MR imaging on T1-weighted fat-suppressed post contrast sequences confirmed a spiculated heterogeneously enhancing mass with mixed kinetics invading the chest wall. Biopsy confirmed fibromatosis. (C) A 46-year-old woman with history of right breast cancer presented with firm mass in right upper outer quadrant. Spot compression mammogram demonstrated an irregular asymmetry at the site of BB marking the palpable area. (D) Ultrasound in the same patient showed an irregular hypoechoic mass with internal heterogeneity. Core biopsy revealed spindle cell lesion. Excisional biopsy confirmed myofibroblastoma. (E) A 46-year-old woman presented for routine screening. Mammogram showed an enlarging asymmetry in the right upper outer quadrant without any microcalcifications (arrows). Ultrasound (not shown) was unremarkable and showed asymmetric breast parenchyma. Due to mammographic appearance, a stereotactic core biopsy was performed, which confirmed PASH.