Multicentric reticulohistiocytosis responding to tumor necrosis factor-alpha inhibition in a renal transplant patient.

Multicentric reticulohistiocytosis (MRH) is a rare systemic disease that characteristically produces severe erosive arthritis of the distal and proximal interphalangeal joints along with cutaneous nodules over the upper extremities and face, but it can be found in other organs. There is no known etiology, and it often remits spontaneously within 5-10 years, but can result in severe disfigurement. The diagnosis is made when histologic analysis of involved synovium or cutaneous nodules reveals characteristic histopathology. We describe a case of MRH manifesting as erosive arthritis that developed despite immunosuppressive therapy. Based on studies reporting tumor necrosis factor-a (TNF-alpha) positive cells within MRH lesions, we began treatment with TNF-alpha inhibition. Within 2 months the patient showed dramatic clinical and serologic improvement that was maintained until she stopped treatment secondary to an upper respiratory tract infection. Once treatment was restarted, the symptoms again improved.