Langerhans' cells in seborrheic keratosis. A clinical and ultrastructural study.

Skin biopsies from 10 patients with seborrheic keratoses were examined by electron microscopy for the presence of Langerhans' cells. Comparing seborrheic keratoses with normal skin of the same patient and with normal skin from controls, neither an increased number of Langerhans' cells nor an increased number of specific granules, Birbeck granules, nor abnormal Langerhans' cells, was found. Melanosomes in a Langerhans' cell were observed in 2 seborrheic keratoses, suggesting phagocytic activity of the Langerhans' cell.