Ultrastructural Study of a Case of Extramammary Paget's Disease of the Vulva

Extramammary Paget's disease of the vulva was found in a 75-year-old woman. The ultrastructural features of Paget cells include rare desmosomes between two Paget cells as well as between Paget cells and adjacent keratinocytes, occasionally giant mitochondria, abundance of cytoplasmic organelles, microvilli, and thick bundles of filaments not connected with plasma membrane. The keratinocytes frequently showed decreased numbers of desmosomes, moderate numbers of plasma membrane extensions resembling microvilli, rarefaction, and dispersion of tonofilament bundles, and an increase in cytoplasmic vesicles and ribosomes. The keratinocyte alterations and Paget cells ultrastructure suggest that Paget cells may originate from keratinocytes.