Image supplied by Fiona Barrett, Specsavers Cannonvale, QLD
A conjunctival intraepithelial neoplasia (CIN) is a pre-malignant or malignant lesion of the eye, confined to the conjunctival epithelium. It falls within the ocular surface squamous neoplasia group and is the most common type of conjunctival tumour seen.
CINs are more prevalent in lighter-pigmented populations, in males and in an older population. UV exposure, smoking, petroleum product exposure, HIV and HPV are potential risk factors with incidence of CIN, although aetiology is still unclear.
A CIN can present as a fleshy, slightly elevated mass, most commonly located within the inter-palpebral zone, near or at the limbus. Appearance can be gelatinous, sessile in nature, or occasionally leukoplakic (having a white plaque on the surface of the lesion). Often there is surrounding corkscrew-like vasculature and slightly abnormal margins.
Patients may complain of conjunctival hyperaemia (redness), noticing the appearance or change of the growth, a foreign body sensation, and pain / irritation.
Clinically, benign, pre-malignant and malignant conjunctival lesions are extremely hard to differentiate. Diagnosis of a CIN in comparison to benign conjunctival lesions (such as pingueculae and pterygia) or malignancies (such as squamous cell carcinoma) can only be confirmed with a biopsy and histological assessment.
Management & Treatment
In an optometric setting, it is important to document size, shape and appearance of any new or existing lesion, and to monitor carefully for any change or growth. Given the clinical difficulty of differentiating the severity of conjunctival lesions, referral for biopsy is recommended for any suspicious lesion to confirm diagnosis. Treatment options can include surgical excision, topical mitomycin C, local chemotherapy, topical 5-fluoracil and interferon.