Microscopic Polyangiitis with Pulmonary-renal Involvement in a Patient with Polyarticular Juvenile Idiopathic Arthritis: A Case Report.

The association of polyarticular juvenile idiopathic arthritis (p-JIA) and microscopic polyangiitis (MPA) is extremely rare. Very few case reports described the coexistence of these two diseases to date. Here we report a 26-year-old female, a diagnosed patient of rheumatoid factor positive p-JIA for 15 years who developed MPA with renal and pulmonary involvement at the age of 26 years. She was successfully treated with intravenous corticosteroid and injection rituximab. This case report is unique as an association between MPA and p-JIA is very rare.