[Melanoma and dysplastic nevus after 8 years of topical Caryolysine]

A 48-year-old woman with poikiloderma atrophicans vasculare was treated with topical mechlorethamine, applied three times weekly, for eight years. After five years treatment she developed nine melanocytic naevi on covered skin. The naevi spread for the next three years and a surgical excision was performed. Pathological examination revealed one level II SSM, one level I SSM and seven junctional naevi with focal dysplasia or melanocytic hyperplasia. The development of melanoma and dysplastic naevi after topical mechlorethamine has not been previously reported. However it seems likely that mechlorethamine was the causative agent. As for the mechlorethamine's imputability in this case, we have used a method combining intrinsic identification of adverse drug responsibility's score, based on the clinical case and on extrinsic identification based on literature evaluation. We suggest that mechlorethamine could act as UV light.