title: Successful treatment of multicentric reticulohistiocytosis with alendronate: evidence for a direct effect of bisphosphonate on histiocytes.
abstract: We describe the case of a 44-year-old Japanese woman with severe nodular erythematous skin lesions and arthritis mutilans who was admitted for further treatment of multicentric reticulohistiocytosis. Skin and synovial biopsies showed heavy infiltration with tartrate-resistant acid phosphatase-positive histiocytes and multinucleated giant cells. Immunohistochemical analysis showed that some of the mononuclear cells in the skin were positive for RANKL. After 1 month of Alendronate, an aminobisphosphonate, given at a dosage of 10 mg once a week intravenously for the first 6 weeks and then once a month thereafter, the arthritis and skin nodules improved, and the remission has continued for more than 2 years. The findings in this patient suggest that osteoclast-like multinucleated giant cells differentiate locally in the skin from infiltrating histiocytes with the help of RANKL-positive stromal cells and that alendronate acts directly on cells of monocyte/macrophage lineage in humans. Thus, alendronate should be added to the list of drugs for the treatment of multicentric reticulohistiocytosis.
authors.affiliation: Osaka City University, Graduate School of Medicine, Osaka, Japan. goto@msic.med.osaka-cu.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Goto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Inaba
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Imanishi
authors.forename: Yasuro
authors.initials: Y
authors.lastname: Kumeda
authors.forename: Kentaro
authors.initials: K
authors.lastname: Inui
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Okada
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nishizawa
mesh_terms: D000328:Adult; D019386:Alendronate / Q000627:therapeutic use*; D001168:Arthritis / Q000188:drug therapy / Q000473:pathology; D005260:Female; D006644:Histiocytes / Q000187:drug effects* / Q000473:pathology; D015616:Histiocytosis, Non-Langerhans-Cell / Q000188:drug therapy* / Q000473:pathology*; D006801:Humans; D012871:Skin Diseases / Q000188:drug therapy / Q000473:pathology
chemical_list: D019386:Alendronate