Successful Treatment of a Patient with Rheumatoid Arthritis and Comorbid Multicentric Reticulohistiocytosis.

Multicentric reticulohistiocytosis (MRH) is a rare disease of unknown pathogenesis, characterized by skin histiocytosis and destructive arthritis. The present study describes a 53-year-old woman who presented with rheumatoid arthritis (RA) and MRH, which is a clinically rare entity. Diagnosis of MRH was based on nodule pathology. Meanwhile, the patient had typical arthritis, was positive for serum anti-cyclic citrullinated peptide (anti-CCP) antibodies and synovitis confirmed by joint ultrasound, and was diagnosed with RA. Her symptoms resolved with glucocorticoids and methotrexate.