[Multicentric reticulohistiocytosis and myelodysplastic syndrome].

Multicentric reticulohistiocytosis (MRH) is a rare disorder of skin and joints, and its aetiology is unknown. We describe a male patient who had first developed osteoblastic lesions of the skeleton in 1976 at the age of 59 years. Three years later, he presented with multiple papular and nodular skin lesions, predominantly on the limbs and upper trunk, and 4 years later he developed painful arthropathy. In 1988 skin examination showed multiple brownish-red papulo-nodules, some of which, at mechanically stressed areas, were ulcerated. The patient complained of pronounced arthrotic disorders with reduced joint mobility. Examination of biopsy specimens from active skin lesions demonstrated extensive numbers of macrophages with partial confluence to giant cells with typical ground-glass cytoplasm. Electron microscopy revealed phagocytosis of collagen-like-structures. Examination of bone marrow biopsy specimens revealed diffuse infiltration by histiocytic cells. The diagnosis made was therefore MRH. The patient was treated for several years with different therapeutic regimens, including azathioprin, dapsone, prednisolon, chlorambucil and cyclophosphamide, and complete remission of skin lesions and of bone marrow infiltration was observed. However, a myelodysplastic syndrome with refractory anaemia and ring sideroblasts developed, which is generally understood to be a preleukaemic condition. Myelodysplastic syndromes commonly develop between 3 and 10 years after the start of a therapy with antineoplastic agents.