Darier disease, also known as keratosis follicularis or dyskeratosis follicularis, is a rare autosomal dominant genodermatosis. It is clinically manifested by hyperkeratotic papules primarily affecting seborrheic areas on the head, neck and thorax, with less frequent involvement of the oral mucosa. When oral manifestations are present, they primarily affect the palatal and alveolar mucosa, are usually asymptomatic, and are discovered in routine dental examination. Histologically, the lesions present suprabasal clefts in the epithelium with acantholytic and dyskeratotic cells represented by corps ronds and corps grains. This paper reports a case of an adult male patient presenting clinical signs of Darier disease in the palatal mucosa and skin on the neck and upper limbs. Intraoral biopsy of the affected area, analysis of family history and evaluation by a multidisciplinary team led to the diagnosis of Darier disease. Dental professionals and pathologists should be aware of these lesions to allow correct diagnosis and proper management of this disease.