Chronic monoarthritis demand an investigation of inflammatory diseases, such as rheumatoid arthritis (RA), infectious diseases like tuberculosis; and other diseases that cause synovitis and joint effusion, such as pigmented villonodular synovitis (PVNS), synovial hemangioma, synovial osteochondromatosis and arborescence lipoma. We report the case of a young patient with chronic right shoulder monoarthritis, who's magnetic resonance imaging (MRI) showed synovitis. Arthroscopy was performed and the biopsy revealed PVNS. CASE REPORT: J C M, 15 years-old, female, Caucasian, student. She was sent to a Rheumatologist along with a diagnosis of juvenile idiopathic arthritis (JIA). The patient presented, for one year, a mild pain of insidious onset in her right shoulder, with relief of the symptoms in two days under nonsteroidal anti-inflammatory therapy (NSAIDs). During this year, the patient presented five or six episodes of pain with the same characteristics. No other signs and symptoms were related. The following tests showed normal or negative results:complete blood count, ESR, C-reactive protein, rheumatoid factor and urinalysis. The antinuclear antibody (ANA) was 1/80 speckled pattern. The MRI of the shoulder showed glenohumeral synovitis with joint effusion and soft tissue swelling in the subscapular bursa, which could correspond to pannus. As the medical history and physical examination were not compatible to JIA, a second MRI was performed, which showed an increase of the synovitis. The patient was submitted to an arthroscopy with biopsy and the histopathological examination showed PVNS. A complete synovectomy was performed and a new MRI, nine months later, showed no synovitis. PVNS of the shoulder is uncommon, and synovectomy was curative in this case.
monoarthritis; pigmented villonodular synovitis; shoulder; synovitis
