RESUMO
INTRODUCTION: Extramammary Paget's disease is a rare histological type of intraepithelial adenocarcinoma that mainly affects apocrine sweat gland-rich areas. Predilection sites include the anogenital region and, less commonly, the axillae. These tumors rarely occur in non-apocrine regions. The aim of this case report is to describe a case of extramammary Paget's disease in the external auditory canal with extensive temporal bone involvement and skull base invasion. CASE PRESENTATION: A 40-year-old Caucasian man presented with a progressively growing, vegetating lesion localized in his right-hand external auditory canal. He had peripheral facial nerve paralysis and complete ipsilateral hearing loss. An incisional biopsy suggested extramammary Paget's disease, and the immunohistochemical analysis confirmed the diagnosis. The tumor was considered inoperable because of the extensive skull base involvement, and he was referred for palliative radiotherapy. CONCLUSION: We report here the third case of extramammary Paget's disease affecting the external auditory canal to be described in the literature. In all the three cases, the prognosis was unfavorable despite treatment.