Rare Giant Cell Tumor of the Distal Flexor Digitorum Longus Tendon Sheath and Early Diagnosis with Use of Magnetic Resonance Imaging.

Giant-cell tumor of the tendon sheath (GCT-TS) is an uncommon occurrence for a foot and ankle surgeon. However, there is a need to recognize the symptoms of typical and atypical presentations of this pathology. These benign neoplasms are recognized clinically as a soft-tissue mass that is usually painless and palpable. The foot and ankle account for only 3% to 5% of all GCT-TS in the body, with most being located in the hand. Giant cell tumor in the tendon sheath occurring in the foot and ankle is usually encountered on the lateral ankle and dorsum of the foot, occupying the extensor tendons. Additionally, it is commonly misdiagnosed clinically. This case study illustrates how early use of magnetic resonance imaging decreased patient morbidity with early recognition and excision of GCT-TS.