• The bone marrow and blood monocytes are precursor cells to the macrophage-histiocyte, the Langerhans cell, the indeterminate cell, the interdigitating cell, and the dendritic cell in the thymus, lymph node, and skin. While there are many histologic and functional similarities in these cell types, some differences do occur. A notable difference is the minimal phagocytosis by the Langerhans cell and the histiocytosis X cell. Non-X histiocytosis is represented by a series of cutaneous disease patterns characterized by localized, nonaggressive, histioxanthomatous skin and mucous membrane lesions, with a tendency to selfheal. Eruptive histiocytoma, juvenile xanthogranuloma, reticulohistiocytoma cutis, papular xanthoma, necrobiotic xanthogranuloma with paraproteinemia, and xanthoma disseminatum are cutaneous patterns of non-X histiocytosis that suggest the possibility of at least two patterns of peripheral macrophage differentiation and pathologic change.
(Arch Dermatol 1981;117:667-672)