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Excerpt from Papilloma, ConjunctivalSynonyms, Key Words, and Related Terms: conjunctival papilloma, papillomatous lesion, benign squamous epithelial tumor Please click here to view the full topic text: Papilloma, ConjunctivalBackground: In general, papilloma is a histopathological term describing tumors with specific morphology. They take on a classic fingerlike or cauliflowerlike appearance. Papillomatous lesions often are lobulated with a central vascular core. Irrelevant of its cytology, a neoplasm of epithelial origin with this form of growth is also called papilloma. Papillomas can be benign or malignant and can be found in numerous anatomical locations (eg, skin, conjunctiva, cervix, breast duct). Specifically, conjunctival papillomas are benign squamous epithelial tumors with minimal propensity toward malignancy.Conjunctival papillomas are categorized into infectious (viral), squamous cell, limbal, and inverted (histological description) based on appearance, location, patient’s age, propensity to recur after excision, and histopathology. They demonstrate an exophytic growth pattern. Interestingly, inverted papillomas exhibit exophytic and endophytic growth patterns. Conjunctival papilloma also can be classified based on gross clinical appearance, as either pedunculated or sessile. The pedunculated type is synonymous with infectious conjunctival papilloma and squamous cell papilloma. The limbal conjunctival papilloma often is referred to as noninfectious conjunctival papilloma because it is believed that limbal papillomas arise from UV radiation exposure. Because of its gross appearance, limbal papillomas are typed as sessile. Although rare, inverted conjunctival papillomas sometimes are referred to as mucoepidermoid papillomas because these lesions possess both a mucous component and an epidermoid component. A strong association exists between human papilloma virus (HPV) types 6 and 11 and the development of conjunctival papillomas. Infectious conjunctival papillomas also are known as squamous cell papillomas. This term arises from its histopathological appearance (ie, the lesion is confined to the epithelial layer, which is acanthotic). Pathophysiology: HPV and polyomavirus are members of the Papovavirus family. These viruses are small (55 nm), naked, and icosahedral with circular double-stranded DNA. Papilloma viruses exhibit site and cell-type specificity, as follows:
Recently, HPV 6a and 45, two new subtypes, have been reported to be associated with conjunctival papilloma.
Transmission is via direct human contact. Proliferation of dermal connective tissue is followed by acanthosis and hyperkeratosis. HPV is tumorigenic, and it commonly produces benign tumors with low potential for malignancy. In general, prolonged proliferation may lead to cellular atypia and dysplasia. Frequency: Although no cross-section epidemiological studies are available, evidence suggests that people without overt clinical presentation may harbor the virus, and HPV DNA can be identified in asymptomatic conjunctiva. HPV types 6 and 11 are the most frequently found in conjunctival papilloma. A published paper reported that HPV type 33 is another source in the pathogenesis of conjunctival papilloma. HPV types 16 and 18 commonly are associated with not only high-grade cervical intraepithelial neoplasia and invasive carcinoma but also squamous cell dysplasia and carcinoma of the conjunctiva. ..... |
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