2020–2021 BCSC Basic and Clinical Science Course™
8 External Disease and Cornea
Chapter 8: Systemic Disorders With Corneal and Other Anterior Segment Manifestations
Multiple Endocrine Neoplasia
Multiple endocrine neoplasia (MEN) is a group of disorders that affect the body’s endocrine system. MEN typically involves tumors (neoplasia) in at least 2 endocrine glands. These growths can be benign or malignant. The condition is classified as MEN 1, MEN 2A, or MEN 2B, depending on the glands involved.
MEN 2 results from a spontaneous mutation of the RET gene, or it is inherited in an autosomal dominant fashion.
MEN 2B is characterized by medullary carcinoma of the thyroid gland, pheochromocytoma, and mucosal neuromas. Patients with MEN 2B have enlarged corneal nerves. In addition, they often have a marfanoid habitus. Conjunctival and eyelid neuromas and keratoconjunctivitis sicca may occur. Patients with MEN 2A also have been noted to have enlarged corneal nerves. Table 8-7 lists other causes of prominent corneal nerves (Fig 8-16) from either true enlargement or increased visibility.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.