SPR Unknown # 102 -- FINAL
4 year-old boy with 8 month history of intermittent knee pain
Publication Date: 2014-01-29
4 year old boy with an 8-month history of intermittent swelling of the left knee, related to physical activity according to the father but not related to any specific injury. There are no other areas of swelling or tenderness such as in the neck or fingers. It was noted in his medical history that at birth there was a positive DAT test for hemolytic anemia. He did not, however, progress to bilirubinemia or show other signs of hemophilia.
There are radiographs which demonstrate moderate swelling of the left knee with cortical irregularity and erosive changes involving the left distal femur. An MRI of the left knee demonstrates heterogeneous T1/T2 hyperintensity with GRE susceptability artifact suggestive of hemosiderin deposits.
Pigmented villonodular synovitis (pathology confirmed)
Pediatric arthropathies are quite rare with an estimated rate of approximately 10 in 100,000. A majority of diagnosed juvenile chronic arthritis are idiopathic. Pigmented villonodular synovitis (PVNS) can be focal or diffuse and is a joint disease characterized by synovial inflammation and overgrowth. PVNS most commonly affects the knees and hips but can affect any joint space, often leading to bony erosions, swelling and pain. Surgery can help decompress the joint but growth often recurs. Radiation treatment has been shown to slow the progression. Differential diagnoses would include: Hemophilic arthropathy, uncalcified synovial chondromatosis, tuberculous arthritis, Trevor's disease, pauciarticular rheumatoid arthritis or a soft tissue hemangioma.