POS1355 THE REMITTING SERONEGATIVE SYMMETRICAL SYNOVITIS WITH PITTING EDEMA SYNDROME (RS3PE): REVIEW OF TEN YEARS AT A REFERENCE HOSPITAL

Background:The Remitting Seronegative Symmetrical Synovitis with Pitting Edema Syndrome (RS3PE) is a rare rheumatological disease, considered a benign process.Objectives:This study aims to describe its clinical features and serological markers, and also to analyze its possible association with neoplasms.Methods:An observational retrospective study was performed to assess demographic and clinical characteristics of patients diagnosed from RS3PE at a reference hospital amongst the Rheumatology and Internal Medicine departments, from 2010 to 2021.Results:Twenty-seven patients were included, with a mean age of 82.74 y.o. (IC95% 80.45-85.04; range 66 to 93), and a 51.85% proportion of males. Only 22.22% were from rural areas.All patients presented bilateral hand edema although some associated feet edema (40.74%) or morning stiffness (70.37%). Blood tests demonstrated anemia in 44.44% of patients. Inflammatory markers were elevated, such as C-Reactive Protein (29.23 mg/L, IC95% 18.17-40.29), erythrocyte-sedimentation rate (33.74 mm/hour, IC95% 24.22-43.26) and fibrinogen (531.6 mg/dL, IC95% 482.91-580.30). Only a few patients presented any autoimmune serological marker such as antinuclear antibodies (18.18%) or rheumatoid factor (8.70%).X-ray screening was realized to 22 patients. 14 showed of osteoarthritis radiologic presentation, 4 had radiological findings of chondrocalcinosis and one of them presented both. Only one patient had bone erosion.Malignancy screening was performed at diagnosis in only 29.63% of patients (all negative). During follow-up only two tumors were detected (mean accumulated follow-up: 40.37 months, IC95% 26.70-54.04; range 1 to 122) and there were adenocarcinoma primary neoplasms.All but one patient received low-dose corticosteroids, with a good and rapid response in all cases. Three patients received treatment with methotrexate (2) or leflunomide (1).Conclusion:RS3PE must be contemplated in elderly patients presenting with bilateral hand pitting edema and articular symptoms. No specific biomarkers have been described, but inflammatory reaction is often found in the absence of rheumatoid arthritis biomarkers. Rapid response to corticosteroids is prevalent. Only two neoplasms were detected during follow-up.References:[1]Paira S, Graf C, Roverano S, Rossini J. Remitting seronegative symmetrical synovitis with pitting oedema: a study of 12 cases. Clin Rheumatol. 2002 May;21(2):146-9. doi: 10.1007/pl00011218. PMID: 12086166.[2]Cobeta García JC, Martínez Burgui J. RS3PE syndrome or benign edematous polysynovitis in the elderly. Study of 8 cases. Rev Clin Esp. 1999 Dec;199(12):785-9. Spanish. PMID: 10687410.[3]Moreno Obregón F, Del Castillo Madrigal M, Díaz Narváez F, Pérez Delgado FJ. RS3PE syndrome with positive rheumatoid factor. Reumatol Clin. 2019 Nov-Dec;15(6):e168-e169. English, Spanish. doi: 10.1016/j.reuma.2017.11.009. Epub 2017 Dec 15. PMID: 29254743Disclosure of Interests:None declared