Clinical effect of tocoretinate on lichen and macular amyloidosis

Abstract

Lichen amyloidosis and macular amyloidosis are commonly therapy-resistant. Tocoretinate is a hybrid compound of retinoic acid and tocopherol that is commonly used for the treatment of skin ulcers. Although beneficial effect of oral retinoic acid on lichen amyloidosis is reported, tocoretinate has not been reported to be useful for the treatment of lichen amyloidosis or macular amyloidosis. We evaluated the effects of topical tocoretinate on lichen amyloidosis and macular amyloidosis lesions. Tocoretinate was topically applied daily to the lesions and clinical improvement and histological changes were evaluated. The outcome was very good for four, good for two, moderate for two and poor for two of 10 treated patients. Epidermal hypertrophy was reduced and expression of involucrin, keratin 1 and keratin 10 was decreased by tocoretinate treatment, suggesting the normalization of epidermal differentiation. Amyloid deposits remained histologically detectable, even in clinically responsive patients. Together, topical application of tocoretinate reduced the clinical symptoms of lichen amyloidosis and macular amyloidosis, and normalized disturbed epidermal differentiation.