Multicentric reticulohistiocytosis-mimicking dermatomyositis. Case report and review of the literature.

Multicentric reticulohistiocytosis is a rare disorder of unknown etiology, characterized by skin and mucosal papulonodular eruptions and destructive polyarthritis. Histopathological study of these lesions shows a nodular infiltrate composed of histiocytes and multinucleated giant cells, with an eosinophilic, granular, 'ground-glass' cytoplasm. We report a case of multicentric reticulohistiocytosis with skin lesions mimicking dermatomyositis and we also review previously reported cases describing such a clinical situation. Our case further emphasizes that multicentric reticulohistiocytosis can mimic clinical features of dermatomyositis. A macular or patch-like erythema in a photodistributed fashion, in addition to other clinical manifestations, can be mistaken for dermatomyositis. However, skin biopsies from these areas may early differentiate both conditions with different treatment options and morbidity. Copyright (c) 2007 S. Karger AG, Basel.