Fibromatosis of breast

  • Aggressive growth of fibroblasts and myofibroblasts
  • Arises typically from pectoralis fascia
  • Hence the mass is often seen closely related to pectoralis major
  • Large spiculated dense lesion
  • Hypoechoic on ultrasound, hypointense on MR sequences with variable enhancement post contrast
  • MRI best for delineating extent prior to excision