MRI of fibromatosis: with pathologic correlation.

Fibromatosis refers to group of benign but sometimes locally aggressive proliferative lesions of myofibroblasts. These are characterized by infiltrative growth, and hence may mimic a malignant lesion. These lesions reveal a low signal intensity on T1-weighted pulse sequences, but may show low or high signal intensity on the T2-weighted sequences. Histologic correlation reveals that the lesion showing low signal intensity on T2-weighted sequences has a larger collagenous component, and reduced cellularity compared with the lesion showing high signal intensity on T2-weighted sequences.