The natural history of multiple endocrine neoplasia type 2A--a clinical analysis

Pheochromocytoma in an 8-year-old patient with multiple endocrine neoplasia type 2A: implications for screening

Childhood pheochromocytoma in the setting of multiple endocrine neoplasia type 2 (MEN2) remains rare and has not been reported under the age of 12. We present an 8-year-old female with known MEN 2A, C634Y RET mutation, diagnosed with a 6 cm pheochromocytoma requiring laparoscopic adrenalectomy. Given this patient's age at diagnosis, screening guidelines should recommend annual screening beginning at age 8 for patients with MEN 2B or MEN 2A codons 630 or 634 RET mutations.

Unusual case of multiple endocrine neoplasia type 2A syndrome without medullary thyroid carcinoma

OBJECTIVE

To present an unusual case of multiple endocrine neoplasia type 2A (MEN 2A) syndrome and to describe how this case differs from the typical clinical features and usual genetic variations seen in classic MEN 2A syndrome.

METHODS

We describe the work-up, diagnosis, and treatment course of a patient who presented with multi-focal pheochromocytomas, parathyroid adenoma, thyroid abnormalities, and a RET mutation.

RESULTS

A 65-year-old man with previously treated pheochromocytoma presented with a parathyroid adenoma, multiple thyroid nodules, and a RET polymorphism. C-cell hyperplasia (CCH) or medullary thyroid carcinoma (MTC) occurs with nearly 100% penetrance in patients with MEN 2A syndrome. Our patient did not have CCH or frank MTC, but he expressed the other manifestations of the MEN 2A syndrome.

CONCLUSION

MEN 2A syndrome is characterized by the occurrence of MTC, pheochromocytomas, and parathyroid hyperplasia or adenomas. It is inherited in an autosomal dominant fashion, and more than 80% of patients with MEN 2A have a specific substitution on codon 634 of the RET proto-oncogene. Despite the nearly 100% penetrance of MTC or CCH in patients with MEN 2A, our patient did not have this. Additionally, he exhibited a RET mutation that is uncommonly seen in classic MEN 2A syndrome. Our patient may have a MEN 2A variant or a pseudo-MEN 2A syndrome.