Histiocytosis X with skin lesions as the sole clinical expression.

The case is presented of a patient with histiocytosis X of the skin of some 25 years' duration. Extensive investigation failed to reveal any other signs of the disease in other organs. The light and electron microscope findings are described. The electron microscope study revealed an abundant cytoplasm with numerous mitochondria, vacuoles, dense bodies, a well-developed Golgi apparatus and numerous Langerhans' cell granules.