Pedigree screening of a Chinese multiple endocrine neoplasia type 2A family and prophylactic total thy-roidectomy / 中华内分泌外科杂志

ABSTRACT

Objective To explore the clinical significance of integrated screening of RET in a Chinese multiple endocrine neoplasia type 2A(MEN 2A)family and to evaluate the feasibility and effectiveness of prophy-lactic total thyroidectomy to MEN 2A-related medullary thyroid carcinoma ( MTC).Methods Medical history was obtained from 10 family members in a 3-generation south China family .Systemic investigations including bio-chemical tests, imaging examinations and germline RET screening were performed .3 asymptomatic mutation car-riers underwent prophylactic total thyroidectomy .Results RET screening showed a heterozygous missense muta-tion of TGC to CGC at codon 634 on exon 11 in 6 members(p.C634R), which was completely consistent with the clinical manifestations.There were 4 males and 2 females.The initial mean diagnostic age of 33.5 years(ranging from 19 years to 65 years) and the mean maximum diameter of MTC was 2.3 cm(ranging from 0.7 cm to 5.2 cm). Among them 3 members had palpable neck masses (1 case with diarrhea).Right total thyroidectomy +right level Ⅵlymph-node dissection with modified right neck dissection in one case , and bilateral total thyroidectomy +bilat-eral level Ⅵlymph-node dissection in 2 were performed .In other 3 asymptomatic mutation carriers , prophylactic total thyroidectomy +bilateral level Ⅵ lymph-node dissection were also performed .Among them, 1 case of a-symptomatic pheochromocytom ( PHEO) underwent cortical-sparing adrenalectomy before MTC .After the first op-eration, 4 patients still presented a high value of calcitonin , among whom 1 patient( T3N 1bM 0-1) underwent re-operation for 3 times after the initial operation and presented metastasis to bone after 130 months, taking vandet-anib orally up to now;2 patients underwent reoperation at 6 and 7 months after initial operation respectively (T1N 1bM0 and T2N 1bM0), and the other one patient was closely monitored and followed up for 22 months(T2N 1b M0).Moreover, The calcitonin levels dropped to normal in the other 2 asymptomatic cases(T1N0M0) who were followed up for 20 months.Conclusions Pedigree screening can work up an early diagnosis and improve the prognosis of MEN 2A.Integrated screening of RET and pre-operative calcitonin level measurement and prophylac-tic thyroidectomy for asymptomatic RET mutation carriers are reasonable and effective .