Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell neoplasm caused by the human T-cell leukemia virus type 1 (HTLV-1). It is characterized by a short survival time and lack of response to chemotherapy. We report a case of a 56-year-old woman, from the Brazilian northeast state of Bahia, who presented with a 2-month history of infiltrated papular and nodular skin lesions, especially on her forehead and also on her lower and upper limbs. Laboratory tests revealed positive serology for HTLV-1. Histopathological findings and the immunohistochemical profile confirmed the diagnosis of adult T-cell lymphoma/leukemia. A month after the diagnosis, the patient presented acute fatigue and pronounced paleness of the skin, dying of septic shock after her first chemotherapy cycle. The aim of this case report was to emphasize the importance of maintaining high clinical suspicion for ATLL, considering the epidemiological profile of the disease, especially for patients whose only early symptoms are cutaneous lesions.