Human papillomaviruses (HPVs) are causative of a group of clinically papillary lesions. The HPV-related lesions of the oral cavity include squamous papilloma, condyloma acuminatum, verruca vulgaris, and multifocal epithelial hyperplasia. Benign entities, such as verruciform xanthoma or giant cell fibroma, as well as malignancies, such as papillary squamous cell carcinoma and verrucous carcinoma, may be considered in the clinical and/or histologic differential diagnoses of these lesions. Mechanisms of infection, epidemiology, clinical presentations, histologic features, and differential diagnoses of the HPV-related oral pathologies are discussed. Current concepts of viral transmission, especially as pertaining to lesions in pediatric patients, and the impacts of HPV vaccination are reviewed.

Ameloblastomas are benign but aggressive odontogenic tumors that most commonly affect the posterior mandible. Approximately 15% occur in the maxilla, with a subset thought to originate from the epithelial lining of the sinonasal cavities. Histologically, sinonasal ameloblastomas are identical to those of the oral cavity, with classical features of palisaded columnar basilar cells surrounding a central proliferation that resembles the stellate reticulum of a developing tooth. Unlike the gnathic variant, sinonasal ameloblastomas tend to affect males more than females, and the incidence of diagnosis peaks at a later age, approximately 60 years old. The overall prognosis is favorable, with local recurrence being the most common long-term sequalae.

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Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is a rare entity. Patients often present with complaints of nasal fullness, obstruction, and epistaxis. It may be confused with metastatic papillary thyroid carcinoma due to its histologic similarity and overlapping immunohistochemical studies, but it is important to distinguish between the two because of differing treatment modalities and prognosis. A significant difference between the two is that despite both entities demonstrating TTF-1 positivity, TL-LGNPPA usually does not stain for thyroglobulin. TL-LGNPPA exhibits indolent growth, with no incidence of metastasis or recurrence after surgical excision.

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