A 70-year-old man with a history of lung adenocarcinoma was admitted to our hospital for chemotherapy. During his hospitalization, eruptive papules with a dermatomal distribution developed on his left chest. He reported a history of herpes zoster with a similar distribution 5 months prior. On physical examination, grouped, vesicle-like papules with erythematous bases were distributed along the left T4 dermatome (Fig. 1a). The lesions were initially treated as recurrent herpes zoster with famciclovir, but new lesions continued to develop.
