Dear Michiel

The giant cell tumor, staged as B3 is a benign bone tumor with characteristics of aggressiveness. The treatment depends on several factors such as the integrity of the articular joint surface, the location and extent of the tumor, patient age and presence of metastases. The aggressiveness in treatment will depend on the histological appearance after the biopsy, which can vary from filling defect with bone graft bone cement, segmental resection and replacement by graft bone bank, arthroplasties and even amputation

The pigmented villonodular synovitis and its tendonsheath analog are usually diagnosed intra operationem (macroscopically) and they should be subjected to wide (total) synovectomy. The diagnosis is confirmed histologically post operationem and its relation to a giant cell tumor as well. So the primary treatment is usually done in general orthopaedic units. In case of recidivs and aggressive growth these patients should be referred to oncoorthopaedic centers. The long-term course of this condition is often unpredictable and they should be followed up with attention.