A Case of Infarcted Localized Tenosynovial Giant Cell Tumor of the Knee: Multimodality Imaging Features and Literature Review

Localized tenosynovial giant cell tumor (L-TGCT), formerly called giant cell tumor of the tendon sheath, is one of the benign proliferative diseases of the synovium of a joint, bursa, or tendon sheath. L-TGCT occasionally involves a large joint such as the knee, and rarely it is combined with infarction by pedicle torsion. Neither the prevalence of torsion of L-TGCT nor the mechanism involved are known, but it is thought to be uncommon progress. Herein, we describe a rare case of infarcted L-TGCT in the knee involving torsion of a mass pedicle in a 47-year-old man. We utilized magnetic resonance imaging including diffusion-weighted imaging and axial apparent diffusion mapping, and sonographic appearance during the course of investigations, because radiologic findings showed characteristic features of infarcted L-TGCT.