29 year old female with right breast retropectoral saline implant. Right breast MLO projection scanned analogue mammogram from outside institution demonstrates focal bulge in the contour of the implant denoted by white arrow.

29 year old female with right breast fibromatosis. 2A: Right breast MLO projection digital mammogram (Hologic Selenia Digital Mammography Unit). 2B: Right breast CC projection digital mammogram. Images demonstrate a partially imaged large retropectoral soft tissue density mass in the right breast with well-circumscribed anterior margins measuring 11.8 × 11.7 × 5.8cm.

29 year old female with right breast fibromatosis. Right breast panoramic view ultrasound demonstrates a hypoechoic solid mass with circumscribed anterior margins measuring 11.3 × 5.7 cm (GE Healthcare LOGIQ E9 Breast Ultrasound Unit utilizing a linear 7.5–15MHz probe).

29 year old female with right breast fibromatosis and left breast saline implant. 4A: Axial T1 weighted breast MR image (TR 565 TE 12; 1.5 Tesla Siemens MAGNETOM Sonata MRI scanner using breast phased array coil; matrix 256×256) showing a right retropectoral breast mass isointense to muscle measuring 10.5 × 6.2 × 10.5 cm. Left breast retropectoral saline implant is hypointense relative to muscle. 4B: Axial T2 weighted MR image (TR 3570 TE 93) showing right breast retropectoral mass with heterogeneous signal intensity. 4C: Axial STIR MR image (TR 5470 TE 70) showing right breast mass with heterogeneous signal intensity.

29 year old female with right breast fibromatosis before and after treatment with tamoxifen.
5A: Axial T1 weighted MR 6 minutes post contrast subtraction image before tamoxifen therapy (TR 6.44 TE 1.4; 1.5T Siemens MAGNETOM Sonata MRI scanner using breast phased array coil; matrix 512×287; 15cc of Magnevist) shows heterogeneously enhancing right retropectoral breast mass measuring 10.5 × 6.2 × 10.5 cm. Left breast saline implant is seen.
5B: Sagittal T1 weighted fat suppressed post contrast image of the right breast before tamoxifen therapy(TR 11.9 TE 5.54; matrix 320×221).
5C: Axial T1 weighted MR 5 minutes post contrast subtraction image 14 months after tamoxifen therapy (TR 4.3 TE 1.51; 1.5T Siemens MAGNETOM Sonata MRI scanner using breast phased array coil; matrix 384×381; 15 cc of Prohance) shows heterogeneously enhancing right retropectoral breast mass that is significantly smaller in size measuring 1.8 × 4.9 × 5.9 cm. Left breast saline implant remains unchanged.
5D: Sagittal T1 weighted fat suppressed post contrast image of the right breast 14 months after tamoxifen therapy(TR 11.9 TE 5.4; matrix 320×221).

29 year old female with right breast fibromatosis. Axial post contrast subtraction image with color mapping (1.5T Siemens MAGNETOM Sonata MRI scanner utilized with dedicated breast coil; evaluation of contrast uptake performed with DYNACAD). The retropectoral right breast mass is blue denoting progressive enhancement. The enhancement curve on the right is confirmatory.

29 year old female with right breast fibromatosis. Medium power view of a core biopsy sample demonstrating a spindle cell neoplasm (H&E stain, 10x).