Immunohistochemistry and electron microscopy in Langerhans cell histiocytosis confined to the skin.

Four cases of benign Langerhans cell histiocytosis limited to the skin were studied. In all three self-healing cases (cases 2, 3, and 4) many dense bodies, myelin bodies, and worm bodies were found. In one chronic case (case 1) none of these was identified. In all four cases, in addition to CD1, HLA-DR, and S-100 stains, interferon-gamma and S-100 beta-subunit were positive in the dermal tumor cells. Both interferon-gamma and S-100 beta-subunits were negative in the normal epidermal Langerhans cells. A comprehensive literature review yielded 87 cases of skin-limited Langerhans cell histiocytosis. These cases could be subgrouped into three categories: (1) those that resolved spontaneously, (2) those that responded to therapy and had no recurrence, and (3) those with persistent or recurrent lesions, not responding to therapy but still limited to the skin.