Reticulohistiocytic Granulomas of the Skin Associated with Arthritis Mutilans

Reticulohistiocytoma or reticulohistiocytic granuloma refers to a nodular lesion of the skin which, despite its rarity, has aroused considerable interest. The tumor may be single or multiple and is composed chiefly of peculiar nonsudanophilic giant cells with single or multiple nuclei and a homogeneous, finely granular, slightly basophilic (sometimes acidophilic) cytoplasm which tends to have a ground-glass appearance. These cells have been interpreted as ganglion cells and as cells of myoblastoma, but the majority of workers have recognized their reticuloendothelial (histiocytic) nature. Of greatest interest is the association of the skin lesions with arthritis of varying degrees of severity, which has been found in 13 cases including the one herein reported. Our case was unusual because of the nature of the arthritis, which was so severe and progressive that it resulted in widespread absorption of bone, ankylosis of many joints, and the final clinical picture of