An unusual case of non-Langerhans cell histiocytosis.

A 28-month-old boy had firm, red nodules for 4 months that were mostly localized to the face. The eruption was preceded by conjunctivitis, eyelid edema, and swelling of the root of the nose. He also had dyspnea, anisocoria with areflexia, swelling of the parotid glands, and hepatosplenomegaly. A bone marrow aspirate showed 25% eosinophils. A skin biopsy specimen revealed a lymphohistiocytic infiltrate that involved the entire dermis. Most of the cells expressed antimacrophage markers; S-100 was negative. Electron microscopy showed poorly differentiated histiocytes without any specific marker. Steroid therapy induced complete clearing. Two years later, after several cutaneous recurrences, the patient is free of disease. We believe that this case represents a nodular, benign non-Langerhans cell histiocytosis with cutaneous lesions that differ from previously described histiocytopathies.