[Multicentric reticulohistiocytosis: A case report].

A 65-year-old woman developed erythema, papules and nodules over the body. Some nodules of her auricles and hands like string beads. Besides, she suffered from symmetrical swelling and pain of multiple joints, morning stiffness with deformity of joints; She had elevated erythrocyte sedimentation rate and C reactive protein levels; Her rheumatoid factor and antinuclear antibody were positive; Joints destruction was found with X-ray imaging; Skin pathology showed Dermal infiltrate of abundant histiocytes, part of them with a ground-glass appearance; A CD68 immunohistochemical stain was positive and the cells were negative for S100, CD1a. These findings were diagnostic evidences of multicentric reticulohistiocytosis (MRH). The patient received high-dose of glucocorticoids combinated with immunosuppressive agents, and achieved a satisfactory effect. MRH was a rare multisystem disease characterized by papulonodular mucocutaneous and destructive arthritis, and its pathogeny was not yet completely understood. The typical lesions of MRH were hard papules or nodules that usually occured on the hands, face and arms. Classic coral bead appearance from periungual cutaneous nodules that were characteristic of MRH. MRH was an inflammatory joint disease, affecting almost all the appendicular joints and characterized by joint multiple, symmetrical, destructive, progressive disability. Joints destruction of the distal interphalangeal joints was a unique feature of MRH. In addition to skin and joints, it could also involve other systems. There were no diagnostic laboratory markers for MRH. Laboratory examinations had often been found to be non-specific. Imageological examination mainly showed bone and joint destruction. Skin biopsy was the best test to diagnose MRH, the typical histopathological findings included an infiltrate with histiocytes and multinucleated giant cells with a ground-glass appearing in eosinophilic cytoplasm, and the immunohistochemical stain was positive for CD68. The diagnosis was typically made based on the clinical presentation, supportive radiographic findings and skin biopsy. MRH was easily possible to mistake for other more common autoimmune conditions, such as rheumatoid arthritis, psoriatic arthritis, osteoarthritis, and dermatomyositis, but the distinctive clinical, radiographic, and histologic features could aid in differentiating these diseases. MRH could mimic other rheumatic diseases, besides, it could also coexist with cancer or other autoimmune disorders. There was no standardized treatment for MRH. However, Nonsteroidal anti-inflammatory drugs, glucocorticoid, Immunosuppressant, biologic medications, and bisphosphonates had been used with varying degrees of curative effect. Treatment with glucocorticoid combined with immunosuppressants were effective for rash and arthritis, early use of them should be strongly considered, and refractory cases could be treated with biological agents. By reporting a MRH case and reviewing literature, this paper aims to help the clinicians improve the understanding of this rare disease, and suggests that when one diagnosis cannot explain the whole picture of the disease, and further evidence should be sought to confirm the diagnosis.