Unusual mitochondrial reaction in psoriatic keratinocytes.

Electron microscopic investigation of skin biopsies revealed that keratinocytes in clinically uninvolved skin from psoriatic patients show the same mitochondrial ring phenomenon after the application of dithranol as has been observed in the cutaneous lesions proper. In various other skin diseases no mitochondrial reaction was evident after dithranol treatment, nor was it seen in chronic dermatitis when dithranol was not applied. It appears, therefore, that this morphological phenomenon is specific to psoriasis and may provide information concerning functional alterations in the pathogenesis of this disease.