Psoriasis and Systematized Epidermal Nevus

Abstract

Multiple lesions of psoriasis circumscribed to those of systematized epidermal nevus occurred in a 31-year-old Japanese woman. She has had extensive verrucose or hyperkeratotic, brownish lesions on the distributional areas of cutaneous sensory nerves originated from the spinal cord C₆-Th₄and L₃-S₁over the right half of her body since birth. Psoriatic lesions first appeared on the brownish lesions at the age of 7 years. Microscopic sections of the psoriatic lesion revealed the same findings as lesions of ordinary psoriasis, losing the histologic features of epidermal nevus. A definite isomorphic response was evoked not only on lesions of epidermal nevus, but also on the apparently normal skin, following a skin abrasion, although most psoriatic lesions had disappeared with parenteral methotrexate therapy.