Presentation
Enlarging foot mass.
Patient Data
There is a large soft-tissue mass dorsal to the metatarsals, with smooth, well-defined erosion of the 3rd metatarsal diaphysis proximally.
There is a large mass arising deep to the extensor digitorum brevis which invades the 3rd metatarsal diaphysis. It shows heterogeneous signal characteristics on STIR, with high signal areas interspersed with smooth amorphous areas of low STIR and T1 signal. These low/low signal areas are not central in location but more peripheral, especially laterally, and show no blooming on the gradient echo scout images. There is avid contrast enhancement throughout the lesion, with the exception of the areas that were consistently low on all other pulse sequences.
A peripheral area of low/low signal tissue is indicated by the blue arrow. This region represents relatively acellular fibrous tissue (see answer to question 1 for more info)
Case Discussion
Path proven aggressive fibromatosis. See article for further discussion.
Thanks to Dr. George Matcuk for sharing this case with me.