Background: Acantholytic acanthoma is a rare benign condition of the skin, commonly solitary, with keratotic surface and a papular or nodular appearance, it is typically asymptomatic, and affects most frequently the trunk. Main observations: In this manuscript we describe an extraordinary case of an acantholytic acanthoma associated to fibrous hyperplasia involving the oral mucosa. Conclusions: We present an exceptional case; to our knowledge, no cases of acantholytic acanthoma affecting oral mucosal membranes have been previously reported in the literature.