Case Study: What is this enlarging lump on a 13 yo girl?

Dr Elaine Wong

Amelanotic Conjunctival Naevus

A conjunctival naevus is a common, benign tumour of the conjunctiva. It is circumscribed, sessile, slightly elevated lesions that can have a cystic component.
It usually appears in the first 2 decades of life. When it first appears, it is usually a non-pigmented sessile mass which becomes darker and larger later on, especially with puberty or pregnancy. Sometimes, the increase in pigmentation may be misleading, as it gives a false impression that the lesion is increasing in size.
They are often located in the interpalpebral conjunctiva, close to the limbus, with no corneal invasion. It is highly mobile over the sclera.

How do you distinguish it from something more malignant?

Benign lesions are more cystic and mobile over the sclera. Malignant lesion may be nodular with feeder vessel and immobile over the underlying sclera. Malignant lesion may arise from surrounding conjunctival melanosis.

How do you monitor this?

Monitoring with photos every 6 – 12 months to detect changes in size or colour. I usually suggest parents to maintain a photo diary themselves with their smart phone.

What is the Prognosis?

The risk of malignant transformation from a conjunctival naevus to a conjunctival melanoma is around 1%. This typically occur around 60-70 yo who presents with a nodular mass. Malignant transformation is nearly unheard of in the paediatric/ adolescent population.

When do you refer for treatment?

If there are any malignant features associated with it or if patient wants removal for cosmetic reasons.