Mammary Paget's disease is clinically defined as skin inflammation of the nipple area and is an adenocarcinoma of the epidermis of the nipple. The pathogenesis of mammary Paget's disease is relatively unknown; nonetheless, there are two popular theories that support the underlying carcinoma and de novo carcinogenesis. For the attending medical practitioner, mammary Paget's disease poses a diagnostic and therapeutic dilemma, especially in the absence of a clinically palpable breast mass. We report a rare case of a 48-year-old Malay woman who presented at Hospital Universiti Sains Malaysia, Kelantan, Malaysia with the symptom of skin erosion on the left nipple and unresponsiveness to multiple topical treatments. A full evaluation and assessment of the patient were conducted, and mammary Paget's disease was diagnosed.