[Cutaneous coumarin necrosis of the breast]

In a 62-year-old female patient petechial haemorrhages of the right breast were observed after the 4th day of treatment with phenprocoumon. Within a few hours large cutaneous necroses developed. Histology showed lymphocytic vasculitis with vessel wall destruction and erythrocytic extravasates as well as necrobiotic changes of the middle and lower corium. High-dosage treatment with prednisolone was started after withdrawal of phenprocoumon. Progression of the necrosis to the left breast could be prevented. However, necrosis of the haemorrhagic area of the right breast could not be arrested. Aetiology and pathomechanisms of coumarin-induced necrosis have to date not been ascertained. Allergic precipitating mechanisms probably were of no importance in our patient.