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Describe the tumours of the conjunctiva.

Ophthalmology · 3rd Professional

Benign Lesions

Lesion	Features
Naevus	The commonest conjunctival tumour. appears in the first two decades at the limbus or in the interpalpebral bulbar conjunctiva; flat or slightly raised, pigmented (though up to a third are amelanotic), and characteristically containing clear cysts. It is mobile over the sclera. May darken at puberty or in pregnancy. Malignant change is rare
Papilloma	Pedunculated and often multiple in children, caused by human papillomavirus types 6 and 11, at the fornix or caruncle; and sessile in adults at the limbus, where it has to be told apart from squamous neoplasia. Recurs after incomplete excision, and excision may seed it, so cryotherapy is combined with excision
Dermoid and dermolipoma	Choristomas — normal tissue in an abnormal site. A limbal dermoid is a smooth, yellowish-white solid mass at the inferotemporal limbus, often containing hair, and may cause astigmatism and amblyopia. Association with goldenhar syndrome (with preauricular skin tags and vertebral anomalies) must be sought. A dermolipoma lies at the outer canthus
Pyogenic granuloma	A fleshy, vascular, rapidly growing mass at a site of previous surgery, trauma or a chalazion; it bleeds readily and responds to steroid or excision
Lymphangiectasia and inclusion cyst	Clear cystic dilatations; harmless
Primary acquired melanosis (PAM)	Flat, patchy, brown pigmentation appearing in middle age in a fair-skinned person; it is unilateral and it changes over time. PAM with atypia progresses to melanoma in a substantial proportion, so it must be mapped, biopsied and followed — it is the important precursor lesion

Malignant Lesions

Ocular surface squamous neoplasia (OSSN) — a spectrum from conjunctival intraepithelial neoplasia to invasive squamous carcinoma. The commonest malignant conjunctival tumour, and of particular importance in India and sub-Saharan Africa
Risk factors — ultraviolet exposure; HIV infection.
Appearance — a gelatinous, leukoplakic (white and keratinised), papilliform or nodular mass at the limbus in the interpalpebral fissure, with prominent feeder vessels; it may spread over the cornea as a translucent sheet with a scalloped edge. It is regularly mistaken for a pterygium, and an atypical or rapidly growing "pterygium" should be sent for histology

Applied Aspects

Send every atypical pterygium for histology; ocular surface squamous neoplasia masquerades as one, and the diagnosis is made in the laboratory
Test for HIV in a young patient with OSSN; the association is strong, the disease is more aggressive, and finding it changes the whole management
Ask when the pigmentation appeared and whether it has changed; new, unilateral, evolving pigmentation in an adult is PAM until proved otherwise

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