Tenosynovial giant cell tumour of the neck.

We report the case of a diffuse tenosynovial giant cell tumour to be found adjacent to the thyroid gland. These tumours, also known as extra-articular pigmented villonodular synovitis, are found more commonly in the fingers, wrist, knee thigh and foot, rarely in the head and neck. These tumours are prone to local recurrence, require a high clinical index of suspicion and if they have atypical features may be extremely difficult to obtain a histological diagnosis.