the induced morphological alterations showed two different stages : ( a ) in the injury stage , seen aftr one week of retinoid administraion , the epidermis was mainly characterized by lack of the horny layer and vacuolar cytoplasmic disintergration of the malpighian layer with intracellular edema and accumulation of some pas-positive material .
C0014520
epidermis
C0221921
horny layer