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.


CONCLUSIONS
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.
Department of Internal Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.
Nicole M
NM
Tyer
Glenn D
GD
Braunstein
David
D
Frishberg
D000368:Aged; D018276:Carcinoma, Medullary / Q000175:diagnosis*; D018278:Carcinoma, Neuroendocrine; D006801:Humans; D008297:Male; D018813:Multiple Endocrine Neoplasia Type 2a / Q000175:diagnosis* / Q000473:pathology; D000090063:Proto-Oncogene Mas; D013964:Thyroid Neoplasms / Q000175:diagnosis