Excerpt from Squamous Cell Carcinoma, Conjunctival

Synonyms, Key Words, and Related Terms: conjunctival squamous cell carcinoma, squamous cell carcinoma of the conjunctiva, conjunctival intraepithelial neoplasia, CIN, SCC

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Background: Squamous cell carcinoma of the conjunctiva is a malignant epithelial neoplasm characterized by basement membrane invasion or distant metastasis. Epithelial tumors of the conjunctiva are similar to conjunctival intraepithelial neoplasia (CIN).

Squamous cell carcinoma of the conjunctiva represents a form of CIN that has either broken through the basement membrane to involve the subepithelial tissue or has metastasized. Morbidity is related primarily to local involvement of the conjunctiva and cornea, although regional spread and distant metastasis are possible. Rarely ocular penetration can occur, particularly with the mucoepidermoid type.

Pathophysiology: Squamous cell carcinoma is believed to arise from limbal stem cells and presents as a mass in the interpalpebral fissure at the nasal or temporal limbus. It may have a gelatinous and velvety, papilliform, or leukoplakic appearance. Given its variable appearance, it may pose a diagnostic challenge as a masquerade syndrome.

Frequency:

In the US: Squamous cell carcinoma is the most common conjunctival malignancy in the United States.

Internationally: Patients who live close to the equator tend to present at a younger age than patients who live more distant from the equator. The incidence of the disease varies geographically, 0.03-3.5 cases per 100,000 people per year.

Mortality/Morbidity: The morbidity from squamous cell carcinoma of the conjunctiva relates to the ocular side effects of the disease and its treatment, as well as regional orbital sequelae, periorbital spread, periorbital sinus involvement, and intracranial involvement. Death may result from distant or regional metastases, as well as intracranial spread.

Race: Squamous cell carcinoma of the conjunctiva is most common in Caucasian individuals.

Sex: Squamous cell carcinoma is more common in males (75%) than in females (25%).

Age: Patients with squamous cell carcinoma of the conjunctiva tend to be elderly, with an average age of 60 years. Patients with acquired immunodeficiency syndrome (AIDS) have a 13-fold increased risk of developing conjunctival epithelial malignancies; these patients also present at a younger age.