Rare case of systemic lupus with manifestation of FS Jaccoud arthropathy: a case report and literature review.

Background: François-Sigismond Jaccoud arthropathy (FSJA) is a rare, secondary joint disease characterised by joint deformities without bone erosions, with a "reducible" pattern. Substantial knowledge exists in this area; however, the pathogenesis of FSJA remains indefinite, and clear diagnostic criteria are lacking. Moreover, preventive measures and specialised treatment interventions for the development of FSJA are needed. Thus, in this novel report, we present the case of a 24-year-old male patient with secondary FSJA, characterised by a prolonged disease course, early atypical symptoms, and an unclear primary systemic lupus erythematosus (SLE) diagnosis. Our objective was to provide further guidance regarding the pathogenesis, diagnosis, and treatment of FSJA secondary to SLE.

Case presentation: The patient presented with a 9-year medical history of polyarthralgia. Furthermore, a generalised rash of the lower limbs and hand deformities manifested over a 6-month duration, with symptoms worsening over a week. Physical examination revealed butterfly-shaped facial erythema, hand deformities, and arthralgia. Radiography revealed joint deformities without bone erosions. Laboratory findings indicated proteinuria, positive antinuclear antibodies, and decreased levels of complement components 3 and 4. Based on the 2019 European League Against Rheumatism/American College of Rheumatology classification criteria, the diagnoses of lupus nephritis (LN) and FSJA, secondary to SLE were made. The patient's SLE LN and joint symptoms improved after a year of intravenous belimumab infusion; in addition to oral methylprednisolone, hydroxychloroquine, and mycophenolate mofetil. Additionally, his hand deformities did not considerably worsen.

Conclusions: FSJA secondary to SLE is rare; nonetheless, further attention and studies regarding this condition are required. Clinically, the differential diagnosis of FSJA should routinely be performed to avoid a misdiagnosis. The manifestation of early joint symptoms without joint deformation requires regular examinations of the joints, in patients with SLE. The early diagnosis and prompt management of FSJA will thus be ensured, reducing the impact on their quality of life.