Multicentric Reticulohistiocytosis

Abstract

A 38‐year‐old woman presented with nodules on the face, scalp, ears, hands and elbows. She also developed fevers, chills, fatigue, weakness, myalgia, joint pain, nausea and weight loss of 40 pounds in eight months. Histology revealed large histiocytes with smooth eosinophilic ground glass cytoplasm, consistent with multicentric reticulohistiocytosis. She was treated with methotrexate 25 mg IM per week and prednisone 10 mg PO QD, with relief of her symptoms and improvement in her skin. Multicentric reticulohistiocytosis is a rare histiocytic systemic disease, with facial and hand skin nodules and symmetric arthritis. Pathognomonic signs include “coral beads” and vermicular erythematous papules bordering nostrils. The histologic hallmark for this disease is a nodular infiltrate of histiocytic cells, including multinucleated giant cells containing an eosinophilic, ground glass cytoplasm. Immunohistiochemistry is positive for CD68 and CD3, and negative for B cell markers as well as Langerhans cell markers. Approximately twenty percent of patients with multicentric reticulohistiocytosis have concurrent malignancy, but there is no one predominant type. The disease usually waxes and wanes for many years, with 30% of patients developing arthritis mutilans. It often regresses approximately seven years after its first appearance.