An 83-year-old man was evaluated for a 1-year history of a pruritic, progressively worsening migratory rash, with associated weakness and a 5-kg weight loss. He had a 30-pack-year history of smoking; he had stopped smoking 45 years earlier.
On examination, he had erythematous skin lesions that appeared in concentric, raised, serpiginous bands, with desquamation
What is the most likely diagnosis?
