Limbal nodule

A limbal nodule is any nodular lesion at the limbus of the eye.
The differential diagnosis for a limbal nodule can include:

Pinguecula
Early Pterygium
Foreign body / foreign body granuloma
Phlycten, an inflamed nodule of lymphoid tissue
Episcleritis
Scleritis
Granuloma
Limbal dermoid, a kind of choristoma
malignant melanoma
naevus

A 1989 case series of 636 limbal nodules examined over a period of 40 years at the Institute of Ophthalmology in London reported that 351 nodules involved malanocytes with two-thirds being benign nevi. Seventy three lesions were squamous cell carcinomas, and 137 premalignant lesions. Ten percent of the lesions were dermoid nodules.