Ocular manifestations in multiple endocrine neoplasia type 2b.

PURPOSE: To describe the clinical and laboratory findings in a patient with multiple endocrine neoplasia type 2b. METHOD: Case report. An 8-year-old boy underwent ophthalmic examination, genetic evaluation, total thyroidectomy, and biopsy of a tongue nodule. RESULTS: Ocular features, including previously unreported iris changes, and their probable origin are discussed. Genetic testing detected the point mutation at codon 918 within the RET protooncogene on chromosome 10, characteristic of multiple endocrine neoplasia type 2b. Histologic analysis of excised thyroid tissue disclosed medullary carcinoma. A tongue nodule proved to be neuromatous. CONCLUSION: Ophthalmologists can play an important role in the recognition of multiple endocrine neoplasia type 2b, a potentially lethal condition.