Electron microscopic investigations on biopsies, taken from one patient with malignant melanoma and two with keratoma palmoplantare, have revealed that many keratinocytes contain numerous intracytoplasmic desmosomes, especially in melanoma. Most of them are interconnected by membrane structures for building large complexes. These intracytoplasmic desmosomes, which are 250–500 nm long and about 80 nm wide, partly show granular contact layer. The attachment plaques are surrounded by either filamentous or granular structures, which possibly induce the formation of the desmosomes. We suppose that these desmosomes partly come into the cytoplasm by invaginations of certain areas of the cell membrane, however, another part may be formed intracytoplasmically after invaginating of such sites of the cell membran