Multiple endocrine neoplasia type 2B：4 cases report and literature review

Abstract

Objective To investigate the clinical characteristics and diagnostic methods of multiple endocrine neoplasia （ MEN） 2B. Methods The clinical data collected from 4 cases with multiple endo-crine neoplasia type 2B, who had been diagnosed and treated from July .1980 to Jan.2012, were retrospec-tively analyzed.Of the 4 patients, 3 males were diagnosed at the age of 14, 24, 21, respectively, and 1 fe-male was diagnosed at age of 23.Two cases had the first diagnosis of thyroid mass during the physical exami-nation, and the adrenal tumors and hypertension were first diagnosed in other two cases , respectively.All four cases had multiple mucosal neuromata .Of whom, three cases had medullary thyroid carcinoma and pheochromocytoma , two cases had Marfan syndrome figure , and one case had pheochromocytoma and Marfan syndrome.Two cases were accompanied by paroxysmal hypertension , and the highest systolic blood pressure was over 200 mmHg （1 mmHg=0.133 KPa）.Two cases of pheochromocytoma were found during follow up . Three cases had bilateral adrenal tumors .The thyroid mass was diagnosed by ultrasonography , and the pheo-chromocytoma was confirmed by ultrasonography , CT and 24-hour urine catecholamine test .Adrenalectomy and thyroidectomy were carried out during the treatment process .To clarify the RET mutation status , exons and adjacent introns from 10th to 16th of RET proto-oncogene were sequenced in two patients . Results Gene analysis of two cases confirmed the activating mutation at the sites of 918 in exon 16 of RET proto-on-cogene in which methionine was replaced by threonine （ ATG-ACG） .Among the 3 cases with medullary thy-roid carcinoma , two patients were treated by total thyroidectomy and neck lymphadenectomy , one was opera-ted by subtotal thyroidectomy .For the treatment of pheochromocytoma , adrenal tumor resection was carried out in 3 cases, but not in the other one .Patients were followed up for 2 to 15 years postoperatively , 1 case without tumor recurrence and metastasis , 2 cases with multiple metastases . Conclusions The diagnosis of multiple endocrine neoplasia type 2B mainly depends on endocrine tests , ultrasonography and CT .Surgery is the primary treatment .When pheochromocytoma coexists with other tumors , pheochromocytoma should be re-moved first . Key words: Multiple endocrine neoplasia; Pheochromocytoma; Thyroid tumor