Etiology • A component of the multiple endocrine neoplasia syndrome
type III (MEN III), (also called type 2b) • Syndrome is related to proliferation of neural crest derivatives,
as follows: • Medullary carcinoma of thyroid • Pheochromocytoma • Mucosal neuromas • Ganglioneuromatosis of the bowel
• Autosomal-dominant transmission • Gene is located on chromosome 10
Clinical Presentation of MEN III • Thickened, prominent lips and frenula • Conjunctival neuromas, corneal nerves • Oral mucosal neuromas: tongue, lips, cheeks, commissures • Marfanoid facies and habitus • Medullary thyroid carcinoma • Oral mucosal neuromas may be initial sign of syndrome
type III (MEN III), (also called type 2b) • Syndrome is related to proliferation of neural crest derivatives,
as follows: • Medullary carcinoma of thyroid • Pheochromocytoma • Mucosal neuromas • Ganglioneuromatosis of the bowel
• Autosomal-dominant transmission • Gene is located on chromosome 10
Clinical Presentation of MEN III • Thickened, prominent lips and frenula • Conjunctival neuromas, corneal nerves • Oral mucosal neuromas: tongue, lips, cheeks, commissures • Marfanoid facies and habitus • Medullary thyroid carcinoma • Oral mucosal neuromas may be initial sign of syndrome
Laboratory Findings of MEN III • Increased serum calcitonin levels • Increased urinary vanillylmandelic acid
Microscopic Findings of Mucosal Neuroma • Plexiform bundles of neural tissue • Axons within bundles
Diagnosis • Confirmation of neuroma presence • Demonstration of increased serum calcitonin
Differential Diagnosis • Neurofibromatosis
Treatment • Thyroidectomy • Follow-up for pheochromocytoma development • Genetic counseling
Prognosis • Guarded, with 100% risk of medullary carcinoma • 50% risk of pheochromocytoma