Histologic study of the ocular lesions in multiple endocrine neoplasia syndrome type IIb.

We studied the clinical and histopathologic findings in the eyes of two patients with multiple endocrine neoplasia type IIb. A prominent clinical feature of this condition is enlarged nonmyelinated corneal nerves composed of bundles of axons associated with Schwann cells. Prominent corneal nerves within an otherwise normal corneal stroma are an important clinical feature of multiple endocrine neoplasia type IIb. Because of this, ophthalmologists are in a position to make an early diagnosis and hence to recommend diagnostic procedures and treatment for the associated potentially fatal medullary carcinoma of the thyroid and pheochromocytomas.