A case of cutaneous zosteriform metastatic carcinoma arising on the healed site of herpes zoster

We report a case of a 67-year-old man presenting with a 2-week history of erythematous zosteriforra indurated confluent nodules and plaques on the right chest which was affected by a herpes zoster infection one month ago. The previous history revealed an adenocarcinoma with malignant pleural effusion on the right hing (stage TV, T4N1M1) 3 months ago. Histopathologic findings showed tumor cells infiltrated throughout the dermis, forming focal glandular structures. We think that me case was the isotopk response in the form of an occurrence of a new skin disorder at the site of another unrelated and already healed skin disease. Many cases of isotopic response have been reported in Korean literature such as lichen planus, granuloma annulare, benign fibrous histiocytoma and reactive perforating collagenosis occurring on the healed site of herpes zoster infection. This is the first report of cutaneous metastatic carcinoma as an isotopic response in Korea.