Extensive cutaneous Langerhans cell histiocytosis in an elderly woman.

Langerhans cell histiocytosis (LCH), especially with involvement limited to the skin in adults is a rare entity. Primary cutaneous LCH in older patients usually follows a benign course and can regress spontaneously. We report a fatal case of disseminated cutaneous LCH in an elderly woman. A 64-year-old woman presented with confluenced erythematous macule and diffuse papuloscaling and papulocrusted lesions on the trunk that became erosive on the area of axillae and groins. Histopathological study of skin specimens showed extensive epidermotropic and folliculotropic, lichenoid infiltration of Langerhans' cells. Positive immunohistochemical staining for CD1a and S-100 protein in Langerhans' cells, and numerous typical Birbeck granules in the cytoplasm of Langerhans' cells by electron microscopy study confirmed the diagnosis of LCH. Chest X-rays and computed tomography scans showed mild interstitial pneumonia without a honeycomb appearance. The patient was diagnosed with LCH. Her general condition worsened rapidly and she died 1 month after diagnosis. Because extracutaneous involvement of LCH had been ruled out by laboratory and imaging investigations, we would like to believe this case should be classified as "malignant" LCH based on the clinical course.