Autologous hematopoietic stem cell transplantation in a patient with rheumatoid arthritis and multiple myeloma: a case-based narrative literature review.

Rheumatoid arthritis (RA) and multiple myeloma (MM) are rare coexisting conditions that present diagnostic and therapeutic challenges, and while autologous hematopoietic stem cell transplantation (auto-HSCT) is standard for MM, its effect on concomitant RA remains unclear. We report a 50-year-old woman with a 10-year history of RA who developed IgG-κ MM and underwent auto-HSCT following VRD induction and high-dose melphalan conditioning. Serial assessments showed that MM response deepened from partial remission to very good partial remission, with M protein declining and the free light chain ratio normalizing, while RA activity markedly improved-rheumatoid factor decreased from 67.8 to 5.5 IU/mL and DAS28-ESR dropped from 4.33 to 2.25, with complete resolution of joint symptoms and no severe transplant-related complications. A review of the relevant literature supports these findings, suggesting that auto-HSCT may be a safe and effective strategy for simultaneously managing both diseases, although long-term follow-up is necessary to confirm the durability of remission.