14-year-old male patient with history of pheochromocytoma, who presented to the ER with thumb pain and noted to have a soft tissue mass in the fifth digit on radiographs. A somewhat lobulated mass measures approximately 1.7 x 0.8 x 2.3 cm (transverse x AP x craniocaudal) centered dorsal to the fifth digit PIP joint and middle phalanx. This lesion demonstrates low T1 signal intensity and high T2 signal intensity with internal low T2 signal septae, which enhance. The underlying osseous cortex appears intact with normal bone marrow signal intensity. The extensor tendons are not clearly delineated within this region. The lesion displaces the normal blood vessels within the dorsum of the finger away from the bone. A linear transverse signal in the distal first metacarpal metaphysis corresponds to linear T2 signal compatible with a nondisplaced fracture with surrounding bone marrow edema.
1. Soft tissue mass about the dorsal surface of the fifth digit PIP joint most likely represents a lymphangioma. 2. Non-displaced transverse fracture of the first metacarpal. 