Multiple endocrine neoplasia 2A (MEN 2A) syndrome.

INTRODUCTION

In the MEN 2A syndrome, which is the most common of the three types of MEN, three endocrine systems are affected simultaneously or subsequently by the development of tumours manifested by medullary thyroid gland carcinoma, pheochromocytoma (often bilateral) and hyperparathyroidism.

MATERIAL AND METHODS

27 patients from 3 families affected by MEN 2A syndrome were examined clinically (by detecting the effects of catecholamine overproduction), biochemically (screening for metanephrine and normetanephrine in the serum), visualization (CT, MRI, MIBG, PET CT) and some of them also genetically (DNA fragment analysis obtained by PCR amplification).

RESULTS

Familial incidence of pheochromocytoma was confirmed in 10 patients (4 males, 5 females and one girl) aged 6 to 54 years (average 22.8 years) . In 5 patients, the pheochromocytoma occurred on both sides, in one patient, with genetically proved MEN 2A syndrome, only one adrenal gland was affected by pheochromocytoma. In 10 patients, mutations were detected in the exon 10, 11 and 16 RET of the proto-oncogene in the centromeric region of the 10th chromosome. After proper preparation, 5 patients underwent bilateral adrenalectomy (unilateral adrenalectomy in one patient). Histological examination of the removed tumours in all cases excluded the malignant pheochromocytoma.The first of the operated patients (54 yr) died after surgery for cardiovascular failure. Others have lived 5 to 15 years after bilateral adrenalectomy without signs of local recurrence of the disease, and have no clinical signs of over-production of catecholamines.

CONCLUSION

Bilateral pheochromocytoma and thyroid carcinoma are indications for detailed clinical and genetic examination of all family members. Bilateral adrenalectomy with lifetime supplementation of adrenal hormones is indicated in symptomatic patients and/or patients asymptomatic with tumours larger than 3 cm in diameter (Tab. 1, Fig. 11, Schema 1, Ref. 31).