🚨Jaren Jackson Jr. Diagnosed with PVNS in knee! *Teaching Point* PVNS stands for Pigmented Villonodular Synovitis of the Knee Now it is often referred to as Tenosynovial Giant Cell Tumor – TGCT) PVNS is a benign but locally aggressive proliferative disorder of the synovium. It most commonly affects the knee (≈75% of cases), typically in adults between ages 20–50. So the knee in a 26 year old fits the profile There are two forms: 1.Localized (nodular) – discrete mass, often anterior compartment 2.Diffuse – widespread synovial involvement (more aggressive, higher recurrence). Jackson’s was localized to the knee. PVNS is now understood as a neoplastic process, not purely inflammatory. It is driven by overexpression of CSF1 (colony-stimulating factor 1), and that leads to recruitment of macrophages. This in turn leads to accumulation of hemosiderin (iron pigment from recurrent microbleeding). Synovial hypertrophy → cartilage damage over time Classic presentation: •Chronic knee swelling •Recurrent large effusions •Stiffness •Dull, aching pain •Mechanical symptoms (locking/catching if nodular) •Often atraumatic onset Athletic patients may be misdiagnosed as: •Recurrent synovitis •Meniscal pathology •Early inflammatory arthritis X-Ray •Often normal early •Late stages → erosions along bone margins MRI (optimal) Key features: (see examples below) •Synovial thickening •Low signal intensity on T1 and T2 •Blooming artifact on gradient echo (due to hemosiderin) •Large joint effusion Treatments 1. Surgical Synovectomy (Primary Treatment) Localized PVNS •Arthroscopic excision •Low recurrence (~10–20%) 2. Targeted Medical Therapy Because PVNS is CSF1-driven: •Pexidartinib •Oral CSF1 receptor inhibitor •FDA-approved for symptomatic TGCT not amenable to surgery •Risk: hepatotoxicity (requires REMS monitoring) Used when: •Recurrence after surgery •Not surgically resectable •Severe functional limitation The long-term prognosis is good in that it is benign (non-cancerous), but it cause progressive cartilage destruction. There is risk of long-term secondary osteoarthritis. The good news is that early intervention improves joint preservation. Jackson’s season is over, but there is a chance he can return early in the 2026-27 season.
