Pigmented Villonodular Synovitis of the Shoulder: A Case Report and Literature Review

BACKGROUND Pigmented villonodular synovitis is a rare clinical entity, with 2-3% of all PVNS cases affecting the shoulder. Diagnosis is challenging and can elude clinicians for years, with definitive treatment involving arthroscopic or open synovectomy. CASE REPORT A 50-year-old woman presented with left shoulder pain persisting for 2 years. She was initially conservatively treated by a rheumatologist, with corticosteroid schemes intra-articularly injected and per os, but no improvement of her symptoms was noted. Two years later, she was referred to the Orthopedics Department of our hospital with constant pain in her left shoulder, refractory to the conservative measures. Physical examination revealed tenderness of her shoulder on palpation and limited range of motion. The diagnosis of PVNS was established by preoperative magnetic resonance arthrography (MRA) and confirmed by biopsy from intra-operative tissue sampling. Arthroscopic debridement and synovectomy were performed, yielding good surgical results, and she now reports pain relief, improved function, and no recurrence of symptoms at 1-year follow-up. CONCLUSIONS The diagnosis of PVNS can be elusive for years. MRI and clinical suspicion along with tissue biopsy can set the diagnosis. Shoulder PVNS follows a similar natural history as knee PVNS, with conservative treatment failing and arthroscopic excision providing definite relief. We report a rare case of shoulder PVNS, underscoring the importance of considering PVNS in cases of shoulder pain refractory to conservative treatment.