Tenosynovial Giant-cell Tumor

Clinical History: 
This 28-year-old woman presented with an approximately 3 year history of slowly-progressive left ankle pain, worse with movement and at the end of the day. After detection of the illustrated mass, surgery was performed with pathologic examination confirming a tenosynovial giant-cell tumor.

Diagnosis:
Tenosynovial giant-cell tumor

MR Technique: 
Scans were acquired at 3 T on a Siemens Verio MR unit. (A) Sagittal pre-contrast spin echo T1-weighted (TR/TE 846/16 ms, scan time 5:42 min:sec) and (B) turbo spin echo fat-suppressed T2-weighted (TR/TE 5010/31 ms, scan time 3:16 min:sec) scans are illustrated, in addition to (C) sagittal post-contrast spin echo fat-suppressed T1-weighted images. The slice thickness was 3 mm in each instance.

Imaging Findings:
An irregular mass demonstrates intermediate signal intensity on T1-weighted images of the ankle. This ill-defined mass is located just superior to the calcaneal tuberosity and extends laterally into the sinus tarsi, involving lateral aspects of the talus and navicular. The lesion exhibits heterogeneous enhancement following contrast administration.