Tenosynovial Giant Cell Tumours: MRI Imaging Pearls - A Pictorial Review

Tenosynovial giant cell tumours (TSGCTs) are uncommon synovial neoplasms arising from the synovium of joints, bursae, and tendon sheaths. Although histologically benign, these lesions may exhibit locally aggressive behaviour, particularly in diffuse forms, leading to progressive joint destruction, functional impairment, and frequent recurrence after surgical treatment. Early recognition and accurate characterization are therefore essential for appropriate management. Magnetic resonance imaging (MRI) is the imaging modality of choice for the evaluation of TSGCT due to its excellent soft tissue contrast and its ability to demonstrate characteristic features related to the tumour’s histopathological composition. Typical MRI findings include low-to-intermediate signal intensity on T1-weighted images, relatively low or heterogeneous signal intensity on T2-weighted sequences, and susceptibility-related blooming artefacts caused by intralesional hemosiderin deposition. Additional features such as synovial proliferation, joint effusion, and bone erosions may further support the diagnosis, particularly in diffuse disease. This pictorial essay provides a comprehensive overview of the imaging spectrum of TSGCT with emphasis on MRI findings and their correlation with underlying pathology. The different subtypes according to the current World Health Organization classification are illustrated. In addition, the complementary role of other imaging modalities such as ultrasound, radiography, and computed tomography is discussed.