Physicians from the Rheumatology and Radiology Departments at the Hassan II University Hospital in Morocco present in this report the rare case of elbow pigmented villonodular synovitis (PVNS).
There are only 15 published cases of this condition. The diagnostic process and successful treatment described here may help others recognize and treat future cases.
Pigmented villonodular synovitis (PVNS) is a benign disease of the joint synovium. Benign in this case means that the condition is confined to the area of involvement. It doesn’t spread or travel to other parts of the body. It does not cause death but disability is possible. The synovium is the layer of soft tissue that lines the joint. It has a clear fluid that helps lubricate the joints.
Symptoms usually include joint swelling of a single joint (knee, hip, ankle, shoulder, elbow — in that order) with pain and loss of motion. Pain and loss of motion get worse as the disease progresses. X-rays often show lytic lesions (bone eaten away). In this case, the 32-year-old woman affected had a huge hole in the back of the elbow called a fenestrated fossa.
But lytic lesions of the bone can be caused by cancer so an MRI and biopsy are required to make an accurate diagnosis. In the case of pigmented villonodular synovitis (PVNS), MRI findings are clear. This is because the tissue contains iron deposits called hemosiderin and the MRI signals clearly show these lesions. Synovial fluid removed from the joint was yellow, another clue as to the diagnosis.
The final confirming diagnostic “test” was surgery to open the joint and remove the tissue, a procedure called synovectomy. With open incision, the surgeon could clearly see the condition. Lots of yellow thickened synovial tissue was visible. Tissue samples sent to the lab provided an examination of the cells, called a histology report to further confirm the diagnosis.
By completely removing all diseased tissue, the patient was able to fully move the elbow again without pain. The disease did not come back again despite other reports that the recurrence rate for PVNS after synovectomy is around 46 per cent for the elbow.
The authors believe their success in this case is due to the fact that the joint was carefully and thoroughly cleaned of all diseased tissue (right down to the bone). Radiotherapy (radiation to the area) is sometimes recommended but this patient did not have that additional treatment. No one knows what causes this disease or the best treatment for it. The authors hope by presenting this case, they can add to the knowledge base about pigmented villonodular synovitis (PVNS).