What is ocular surface squamous neoplasia (OSSN)?
OSSN encompasses a wide spectrum of abnormal-growth dysplastic squamous epithelial cells on the surface of the eye. These tumors typically appear in older people, especially those who have had significant exposure to sunlight. Ocular surface neoplasia often appears as tiny growths on the surface of the eye and may be mistaken for ptergium.
What are the risk factors for OSSN??
They likely involve a variety of environmental factors, including UV radiation and exposure to sun. OSSN can also be linked to viral infections, chemical carcinogens, and other environmental risk factors. It is well known that the prevalence of OSSN increases in populations that live near the equator. OSSN is also more common in Caucasians with light complexions and patients with xeroderma pigmentosum, a genetic condition that increases susceptibility to DNA alterations secondary to UV light.
The most common form of OSSN is conjunctival intraepithelial neoplasia (CIN), a noninvasive, slow growing tumor that arises from a single mutated cell on the ocular surface. Rarer forms of OSSN include squamous cell carcinoma (SCC), a malignant lesion in which the dysplastic epithelial cells have penetrated the corneal basement membrane (gaining metastatic potential) and mucoepidermoid carcinoma, a rarr and aggressive variant of SCC, which may be clinically distinguishable from SCC only through special testing.
How is ocular surface neophasia (OSSN) treated?
The history of the lesion and number of prior treatments often dictate tumor management. Major breakthroughs in the diagnosis and treatment of the disease have occurred within the past two decades. These include increasing use of topical chemotherapeutic agents over surgery. Interferon-α2b, mitomycin C, and 5- fluorouracil have the advantage of treating the entire ocular surface and avoiding surgical complications such as positive tumor margins, scarring, and limbal stem cell deficiency. If the tumor is large or recurrent, surgical removal is often recommended. The Ocular Oncology Service at New York Eye and Ear Infirmary of Mount Sinai (NYEE) has extensive experience diagnosing and treating these often complex conditions.