Non-Hodgkin lymphoma

A 46-year-old man comes to his physician for assessment of a pruritic rash for the past two months. The patient states he has tried calamine lotion and several emollients with minimal relief. He has not used any body washes or creams. The patient has a remote history of intravenous drug use but has not used in the past year. Vital signs are within normal limits. Examination reveals a scaly rash over the chest, back, and legs. A photograph of the rash is shown. A biopsy of one of these lesions exhibits clusters of abundant lymphocytic cells with cerebriform nuclei within the epidermis and dermis. Which of the following is the most likely diagnosis?