A 14-year-old boy is brought to the office due to painless nodules on his lips and tongue. The lesions appeared several months ago and have been progressively enlarging. The patient underwent total thyroidectomy 5 years ago following the discovery of a thyroid mass and takes replacement thyroid hormone. On physical examination, the patient is tall and slender with disproportionately long arms and legs. His fingers are also long and thin, and joint laxity is present. Eye examination is normal and oral inspection reveals several small, soft, flesh-colored papules on his lips and tongue. Serum TSH is within normal limits. This patient most likely has which of the following conditions?
Classification of multiple endocrine neoplasia | |
Type 1 |
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Type 2A |
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Type 2B |
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This patient has a marfanoid habitus—a tall and slender build with disproportionately long arms, legs, and fingers. The flesh-colored nodules on his lips and tongue are likely mucosal neuromas, which are unencapsulated, thickened proliferations of neural tissue. This patient also has a history of total thyroidectomy, which was likely due to medullary thyroid cancer (MTC). This combination of clinical findings is consistent with multiple endocrine neoplasia type 2B (MEN 2B), which is due to an autosomal dominant germ-line mutation in the RET proto-oncogene.
Other possible manifestations of MEN 2B include pheochromocytoma and intestinal ganglioneuromas (which may cause constipation). The earliest manifestations of the disease often appear in childhood or adolescence. Early recognition of MEN 2B is important as almost all patients develop MTC and prophylactic thyroidectomy can be life-saving.
(Choice A) Ehlers-Danlos syndrome is a heritable connective tissue disorder characterized by skin hyperextensibility, joint hypermobility, tissue fragility, poor wound healing, and easy bruising. There is no known association between Ehlers-Danlos syndrome and thyroid cancer or perioral nodules.
(Choice B) Although this patient has a marfanoid habitus, the remainder of his presentation is more consistent with MEN 2B than Marfan syndrome. In addition, unlike true Marfan syndrome, patients with MEN 2B do not develop aortic malformations (eg, dilation) or ocular malformations (eg, ectopia lentis).
(Choice C) Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant condition characterized by parathyroid adenomas with hyperparathyroidism, anterior pituitary gland tumors, and pancreatic endocrine tumors (the "3 Ps"). MEN 1 is not associated with thyroid cancer or perioral nodules.
(Choices E and F) Neurofibromatosis type 1 is characterized by café au lait spots, cutaneous neurofibromas, axillary or inguinal freckling, optic glioma, and iris hamartomas. Neurofibromatosis type 2 (the more central form) is characterized by bilateral acoustic neuromas, brain meningiomas, and schwannomas of the dorsal roots in the spinal cord. Although this patient has (mucosal) neuromas, the remainder of his presentation is more consistent with MEN 2B.
Educational objective:
Multiple endocrine neoplasia type 2B is characterized by medullary thyroid cancer, pheochromocytoma, marfanoid habitus, and oral and intestinal mucosal neuromas.