ABSTRACT
<p><b>OBJECTIVE</b>To analyze the manifestation and investigate the value of MRI in the diagnosis of giant cell tumor of tendon sheath (GCTTS).</p><p><b>METHODS</b>Twenty patients with GCTTS proved by operation and pathology were retrospectively analyzed. There were 8 males and 12 females. The average age was 35.5 years, range from 15 to 61 years. All the patients underwent MRI examination.</p><p><b>RESULTS</b>Among the 20 cases, 16 patients had the tumor in knee joint, 2 patients had the tumor in interphalangeal articulation of foot and ankle joint respectively. Nineteen patients had limited tumor and 1 patient had diffuse tumor. The soft tissue mass localized beside lower extremity osteoarticulation was displayed on MRI images. On T1WI, the signal intensities of GCTTS almost equaled to those of skeletal muscle in 15 cases and were slightly lower than those of skeletal muscle in 5 cases. On T2WI, the signal intensities tended to range between those of skeletal muscle and fat in 4 cases, almost equaled to those of skeletal muscle in 13 cases, and were slightly lower than those of skeletal muscle in 3 cases. In the 16 patients with gadolinium-enhanced images on T1WI, 5 patients showed homogeneous enhancement and 11 patients showed inhomogeneous enhancement. Four patients had adjacent bone destruction.</p><p><b>CONCLUSION</b>The location, shape and inner signal characteristic of GCTTS localized beside lower extremity osteoarticulation could be demonstrated clearly by MRI examination, which is valuable for clinical diagnosis, guiding treatment and follow-up visit.</p>