Cowden's disease is an autosomal dominant disorder caused by mutation of the phosphatase and tensin homologue deleted on chromosome 10 (PTEN). Cowden's disease is characterized by symptoms such as hamartomas developing in multiple organs, papillomatous hyperplasia, and papules on the face or limbs. We describe a 69-year-old woman with a chief complaint of gingival swelling who was found to have multiple papillomatous hyperplastic lesions of the maxillary and mandibular gingiva within the oral cavity and small papules on the skin of the neck. Upper gastrointestinal endoscopy revealed multiple polyps in the esophagus and stomach. Cowden's disease was diagnosed after detection of the PTEN mutation on genetic analysis. Caution is required in differential diagnosis when multiple papillomatous papules are present within the oral cavity, because this could be an oral symptom of a disorder such as Cowden's disease.
