Plantar fibromatosis: a benign aggressive neoplasm with a characteristic appearance on MR images.

PURPOSE

To define the magnetic resonance (MR) imaging characteristics of plantar fibromatosis.

MATERIALS AND METHODS

Sixteen patients (19 feet) with proved plantar fibromatosis underwent preoperative MR imaging at 1.5 T. A control group of 19 people (24 feet) also underwent MR imaging.

RESULTS

Twenty-seven lesions (mean size, 2.2 x 1.0 cm) were identified. All had infiltrative upper margins. Four (15%) of the 27 grew deep to the aponeurosis; 25 (92%) exhibited some signal intensity heterogeneity. All 27 of the lesions on T1-weighted conventional spin-echo (SE) images, seven (78%) of the nine on T2-weighted conventional SE images, and 17 (94%) of the 18 on T2-weighted fast SE images were isointense to minimally hyperintense (to the signal intensity of adjacent muscle). Five (83%) of the six lesions on short inversion time inversion-recovery images were hyperintense. Enhancement was variable on contrast material-enhanced images; nine (60%) of the 15 lesions on these images showed marked enhancement.

CONCLUSION

Plantar fibromatosis is a benign but infiltrative neoplasm with a characteristic location and appearance on MR images.