Paraganglioma in a patient with the multiple endocrine neoplasia type I: unusual feature of MEN I, mixed MEN I and MEN II, or MEN IV?
Abstract
The patient, born in 1964, has been followed since her youth in endocrinology out-patient department of the 3 Department of Internal Medicine at the 1 Faculty of Medicine in Prague for the first type of multiple endocrine neoplasia (MEN I), where prolactinsecreting pituitary adenoma, parathyroid adenoma and glucagonoma were gradually discovered. All of these endocrine tumors are among the typical neoplasms occuring in MEN I.
However, mediastinal paraganglioma developed in this patient as well. Tumors derived from neural crest, especially adrenal medulla tumors (pheochromocytoma) and paragangliomas, are typical for the second type of multiple endocrine neoplasia (MEN II).
The MEN I was found positive in patient's family history, but neither paraganglioma nor pheochromocytoma has been developed in any member of her family. Genetic testing proved that the patient is not a carrier of RET mutations that are typical for MEN II.
Genetic testing neither for MEN I nor for other known genes which mutations are associated with increased risk of hereditary paraganglioma have not been carried out yet. The question is whether an overlap of both multiple endocrine neoplasia syndromes has occured in our patient or mediastinal paraganglioma is an exceptional tumor under the MEN I or it may be the MEN X syndrome proven in laboratory rodents and in humans known as MEN IV.