The objective of this paper is to report a case of extramammary Paget disease of the vulva, to describe its diagnosis, surgical treatment, and outcome, and to discuss the general characteristics of this pathology. This is a rare neoplasm, found principally in areas in which apocrine and eccrine glands are numerous. This case report is relevant to the literature since the differential diagnosis of extramammary Paget disease is difficult to be done only with the macroscopic appearance of the lesion and even with the microscopic characteristics, requiring further studies, immunohistochemistry, as to differentiate pathologies. The present report describes the case of a 63-year-old patient at the Santa Casa de Misericórdia Hospital in Vitória, Espírito Santo, Brazil, who presented with a hardened, ulcerated, and purplish lesion with hyperchromic and hypochromic spots, measuring 4 cm in diameter, located on the lower third of right labium majus, close to the vaginal fourchette. A right hemivulvectomy was performed, leaving wide margins all around. The patient progressed satisfactorily following surgery. Although extramammary Paget disease is rare, its incidence increases as a function of the patient's age. Patients should be followed up closely because of the risk of persistence and/or recurrence of the disease.