At the ulnar side of the middle phalanx of the 4th digit there is a soft tissue lesion. This extends anteriorly and posteriorly around the phalanx, abutting the periosteum but without cortical or marrow signal change. The lesion intimately abuts the flexor tendons, however there is no intra-synovial or intra-articular involvement.
Signal characteristics of the lesion: isointense to muscle on T1, with heterogenous enhancement.