Intramuscular Tenosynovial Giant Cell Tumor Harboring a Novel CSF1-CD96 Fusion Transcript

Tenosynovial giant cell tumors typically arise in the synovium of joints, bursae, or tendon sheaths. They may occur in an intra- or extra-articular location and can be divided into localized and diffuse types. The neoplastic nature of the lesion has been supported by a recurrent CSF1 gene rearrangement in a small subset of lesional cells, of which the most common fusion partner is COL6A3. Herein, we report a case of intramuscular localized tenosynovial giant cell tumor harboring a novel CSF1-CD96 fusion transcript, thus expanding the molecular profile of this tumor.