Fig. 13

GCTTS in a 23-year-old female presenting with a 1-year history of right thumb swelling and mild pain. (a) Plain radiograph shows well-defined lucency at the head of the first metacarpal (arrow). (b) T1w sequence shows a lobulated subcutaneous lesion of intermediate signal encasing the flexor pollicis longus tendon (arrow). (c) The lesion shows heterogeneous high signal on T2w-FS sequence. There is pressure erosion on the underlying bone. (d) Foci of susceptibility are demonstrated on the GRE sequence (arrow). (e) There is avid and fairly homogeneous enhancement