Distinguishing bowenoid papulosis from Bowen disease in the mouth: A case report.

Bowenoid papulosis (BPap) is an uncommon skin disorder linked to human papillomavirus (HPV) infection and characterized clinically by the presence of scattered papules or small plaques, multiple and pigmented, that involve the stratified squamous epithelium. Bowen disease (BD) is recognized as the main differential diagnosis of BPap. An 80-year old white woman was referred for the evaluation of multiple, brown verrucous papules measuring 3 to 4 mm in diameter on the right maxillary gingiva. Histopathological analysis revealed disturbed epithelial maturation with papillary stratified squamous epithelium, koilocytic dysplasia, parakeratosis, acanthosis, basal double-layer, loss of cellular polarity, nuclear hyperchromatism and pleomorphism, scattered mitosoid bodies, and a high degree of cytologic atypia. An immunohistochemical investigation for p53 and Ki67 showed staining of the basal and suprabasal layer, while p16 was strongly expressed in the nuclei of epithelial cells and Bcl-2 was positive only in mitosoid bodies and the lymphocytic inflammatory infiltrate. In situ DNA hybridization was negative for HPV. Oral BPap is an uncommon lesion in which the diagnostic process includes clinical, histopathological, and molecular correlations due to the similarity to aggressive behavior lesions such as BD.