RESUMO
INTRODUCTION: Tamoxifen is widely used for the treatment of hormone-responsive breast cancer. In this article, we report a case of a patient who developed hand deformities following long-term administration of tamoxifen. CASE REPORT: A 57-year-old woman, followed for invasive ductal carcinoma of the left breast under tamoxifen for 7 years, presenting joint pain with deformities in her fingers. MANAGEMENT & OUTCOME: Following the appearance of the adverse effect, tamoxifen was stopped. A series of biologic and radiologic analysis were performed in order to explain the appearance of this event. A substitution treatment was discussed and a rheumatologist's opinion was requested. DISCUSSION: Tamoxifen appears to be associated with the development of inflammatory osteoarthritis resembling rheumatoid arthritis. Possible mechanisms of such an effect are discussed.