Tenosynovial juxta-articular giant-cell tumour of the knee--an unusual location of the tumour.

We present a case of a physically active 46 year-old woman who was treated operatively for a juxta-articular tenosynovial giant cell tumour of the knee that caused mechanical symptoms. The preoperative diagnosis was retropatellar lipoma. The tumour was located in the infrapatellar fat pad. No recurrence was observed by MRI in 1-year follow-up.