A case of multicentric reticulohistiocytosis

A 47-year-old woman had noticed scattered erythema on the forehead about two years previously. These skin eruptions gradually extended to the whole face, neck and forearms with multiple nodules on her hands, accompanied by arthralgia. At her first visit to our hospital, a physical examination revealed aggregated red papules, 3-4 mm in size, on the face, auricles and neck, and small erythemal patches scattered on the forearms. Small brownish red nodules were present on the fingers with the joints swelling. Arthritis of both shoulders and hip joints were observed by computed tomography, and an X-ray roentgenogram showed arthritis of multiple finger joints. A histopathological examination of a skin nodule revealed a diffuse infiltration of histiocyte-like cells with eosinophilic and ground-glass like cytoplasm in the dermis. Multinucleated histiocytes were positive for CD68 and CD10. We diagnosed this case as multicentric reticulohistiocytosis based upon these findings. No evidence suggesting internal malignancy was observed. The patient was treated with oral prednisolone 20 mg/day in combination with oral methotrexate 6 mg/week, which stopped the progression of the arthritis and gradually improved the skin eruptions.