[Ultrastructural study of Mibelli's porokeratosis. Pathogenic and therapeutic considerations in three cases].

Report of three cases of porokeratosis Mibelli with emphasis on the ultrastructural changes of the entire epidermis underlying the cornoid lamella: autophagocytosis, filamentous degeneration, formation of "corps ronds". These phenomena are correlated with those of apoptosis (or intraepidermal cellular death with filamentous degeneration). Its role in the genesis of the cornoid lamella and in the degeneration of the lesions is discussed. In conclusion, on the basis of the reported observations and of the studies showing the action of retinoic acid and its derivatives on precancerous lesions, the authors propose to treat the actinic disseminated form of porokeratosis Mibelli with the aromatic derivative of retinoic acid (RO 10 9359).