Case report of a young man showing neuromas of the palpebral and bulbar conjunctiva and markedly thickened nerve fibers in both cornea. Multiple neuromas were seen on the lips and in the oral cavity. A medullary carcinoma of the thyroid was found. These symptoms pointed to the diagnosis of a MMN or MEN type 3 syndrome. There were no signs of phaeochromocytoma, however, which also belongs to this syndrome. The ophthalmologist, who may be the first to see such a patient as a child, should be aware of the malignancies which develop around puberty and of the strong and dominant heredity of this disease.