Results of early thyroidectomy for medullary thyroid carcinoma in children with multiple endocrine neoplasia type 2

Diagnosis and management of pediatric endocrine neoplasms

PURPOSE OF REVIEW

To guide the clinician in the diagnostic evaluation of endocrine neoplasms, to distinguish between benign and malignant and determine when surgical referral is indicated.

RECENT FINDINGS

Thyroid nodules are uncommon but malignant in as many as 27% of patients. Fine needle aspiration should be considered in adolescents, in which accuracy is as high as 90%; surgical resection should be undertaken in all preadolescents (<13 years) with a thyroid nodule. Prognosis for most primary thyroid malignancies is favorable. Primary hyperparathyroidism is rare and due to an adenoma in up to 70% of patients. Surgical resection carries a cure rate of 95% with the use of intraoperative parathyroid hormone assays. Adrenal neoplasms cover a wide spectrum of disorder. They are functional in 95% of patients and require a thorough diagnostic evaluation prior to surgical resection. Malignant lesions of the adrenal gland carry a poor prognosis when complete surgical resection cannot be achieved. Carcinoids are rare neuroendocrine neoplasms, primarily of the appendix, associated with carcinoid syndrome in 10% of patients. The indolent course warrants aggressive surgical control.

SUMMARY

Endocrine neoplasms are unusual in the pediatric population. Their presence should raise concern about a multiple endocrine neoplasia syndrome and appropriate diagnostic and endocrine work-up. Most neoplasms will require surgical resection.

Medullary Thyroid Carcinoma

Medullary thyroid carcinoma is a neuroendocrine tumor derived from the C cells of the thyroid gland and accounts for approximately 5% of all thyroid carcinomas. Approximately 30% of the cases are associated with an autosomal dominant syndrome called multiple endocrine neoplasia type 2, and the identification of these individuals is important because affected family members may benefit from an early diagnosis. The treatment of this disease is predominantly surgical, and the impact of radiotherapy and chemotherapy is limited. The identification of the associated molecular events has lead to the development of specific molecular targeted agents that may change the way this disease is treated in the near future.

Self-Surveillance for Genetic Predisposition to Cancer: Behaviors and Emotions

PURPOSE/OBJECTIVES

To describe the kinds of self-monitoring activities and the emotional responses associated with those activities in patients with a genetic predisposition to multiple endocrine neoplasia type 2a (MEN2a) or familial adenomatous polyposis (FAP).

RESEARCH APPROACH

Thematic analysis of the transcripts of patient interviews conducted for two previous grounded theory investigations of participation in lifelong surveillance for patients with cancer predisposition syndromes and their family members.

SETTING

In the original studies, participants were recruited through a high-risk gastrointestinal cancer clinic (for FAP) and pediatric and adult endocrinology clinics (for MEN2a) at two eastern U.S. medical centers and by patient referral.

PARTICIPANTS

58 transcripts of interviews with 29 patients; 17 diagnosed with FAP or the variants of Gardner syndrome and attenuated FAP and 12 patients diagnosed with MEN2a.

METHODOLOGIC APPROACH

Informants participated in two hour-long, in-depth interviews and completed a self-administered sociodemographic questionnaire.

MAIN RESEARCH VARIABLES

Types of self-surveillance activities.

FINDINGS

Patients engage in an elaborate set of self-surveillance activities that are grouped into five categories of behavior: Medication Appraisal, Phenotype Tracking, Intake and Output Monitoring, Laboratory and Treatment Recording, and Tracking of Visits. Self-surveillance behaviors are grouped independent of type of syndrome, penetrance, age, or gender of the patient. Each category comprises a variety of behaviors that correspond with treatment recommendations and understanding of the disorder.

CONCLUSIONS

Self-surveillance may be driven by a combination of anticipation and the need for control and understanding.

INTERPRETATION

Findings from the study could be used to create an assessment tool to evaluate the extent to which patients are involved in day-to-day self-monitoring. Clinicians may use the categories to better understand patients' knowledge deficits and the emotional impact of enhanced vigilance. Self-surveillance activities performed by patients with MEN2a and FAP also may be performed by patients with other cancer predisposition syndromes.

An introduction to managing medullary thyroid cancer

MTC is a rare neuroendocrine thyroid tumour accounting for 3% to 10% of all thyroid malignancies. It can occur in a sporadic and a hereditary clinical setting. Hereditary MTC may either occur alone (familial MTC, FMTC) or as part of multiple endocrine neoplasia (MEN) type 2A, or MEN 2B. These disorders are due to germline mutations in the RET (REarranged during Transfection) gene. In carriers of MEN 2B-associated RET mutations, prophylactic thyroidectomy is indicated before the first year of life. In the case of MEN 2A-associated germline RET mutations with a high-risk profile, total thyroidectomy is warranted before the age of 2 years and certainly before the age of 4 years. At that age the risk of invasive MTC and metastases is acceptably low. Depending on the type of RET mutation, thyroidectomy can take place at an older age in patients with a lower risk profile. In case of elevated basal or stimulated serum calcitonin, preventive surgery including total thyroidectomy and central compartment dissection should be performed regardless of age. When MTC presents as a palpable tumour, total thyroidectomy should be combined with extensive lymph node dissection of levels II-V on both sides and level VI to prevent locoregional recurrences.

Hereditary hormone excess: genes, molecular pathways, and syndromes

Hereditary origin of a tumor helps toward early discovery of its mutated gene; for example, it supports the compilation of a DNA panel from index cases to identify that gene by finding mutations in it. The gene for a hereditary tumor may contribute also to common tumors. For some syndromes, such as hereditary paraganglioma, several genes can cause a similar syndrome. For other syndromes, such as multiple endocrine neoplasia 2, one gene supports variants of a syndrome. Onset usually begins earlier and in more locations with hereditary than sporadic tumors. Mono- or oligoclonal ("clonal") tumor usually implies a postnatal delay, albeit less delay than for sporadic tumor, to onset and potential for cancer. Hormone excess from a polyclonal tissue shows onset at birth and no benefit from subtotal ablation of the secreting organ. Genes can cause neoplasms through stepwise loss of function, gain of function, or combinations of these. Polyclonal hormonal excess reflects abnormal gene dosage or effect, such as activation or haploinsufficiency. Polyclonal hyperplasia can cause the main endpoint of clinical expression in some syndromes or can be a precursor to clonal progression in others. Gene discovery is usually the first step toward clarifying the molecule and pathway mutated in a syndrome. Most mutated pathways in hormone excess states are only partly understood. The bases for tissue specificity of hormone excess syndromes are usually uncertain. In a few syndromes, tissue selectivity arises from mutation in the open reading frame of a regulatory gene (CASR, TSHR) with selective expression driven by its promoter. Polyclonal excess of a hormone is usually from a defect in the sensor system for an extracellular ligand (e.g., calcium, glucose, TSH). The final connections of any of these polyclonal or clonal pathways to hormone secretion have not been identified. In many cases, monoclonal proliferation causes hormone excess, probably as a secondary consequence of accumulation of cells with coincidental hormone-secretory ability.

Bringing threat to the fore: participating in lifelong surveillance for genetic risk of cancer

PURPOSE/OBJECTIVES

To explain how patients with multiple endocrine neoplasia type 2a (MEN2a) and family members conceptualize participation in lifelong surveillance in genetic cancer care.

DESIGN

Qualitative naturalistic inquiry.

SETTING

Northeastern United States. Data were collected during interviews in informants' homes.

SAMPLE

12 adult patients and 9 family members were recruited purposively through endocrinology clinics at two East Coast medical centers.

METHODS

A grounded theory design was used. Subjects completed a demographic questionnaire and were interviewed on two occasions. In-depth interviews were audiotaped. The core concept and process variables emerged through three levels of narrative content analysis, theoretical sampling, and constant comparison. The generated theory was presented to the participants for validation.

MAIN RESEARCH VARIABLES

The basic psychological issue associated with participation in lifelong surveillance and the psychosocial processes used by individuals to deal with the issues.

FINDINGS

MEN2a patients and family members experience surveillance as a (Re)Minding of a threat to health. Once threat is brought to the fore, participants interpret the meaning and negotiate control of the impact of the diagnosis, related events, and consequences. Meaningful information from surveillance activities is incorporated into participants' self-image and daily lives through a process of (Re)Integration. The genetic nature of MEN2a did not emerge as a significant subcategory in relation to the core variable.

CONCLUSIONS

Finding meaning in the outcomes of surveillance events is a psychosocial process that is central to participation in lifelong surveillance. Genetic predisposition to cancer was a peripheral concern to subjects as they dealt with surveillance issues.

IMPLICATIONS FOR NURSING

This investigation provides a model for the development of a grounded theory for understanding how people with other genetic cancer syndromes participate in lifelong surveillance.

Acceptable age for prophylactic surgery in children with multiple endocrine neoplasia type 2a

AIMS

Germline mutated RET proto-oncogene, causing multiple endocrine neoplasia (MEN)-2a syndrome is the indication for prophylactic total thyroidectomy. Literature regarding the risk and the extent of early surgical intervention is scarce and the optimum age for surgery is still controversial. To optimize management in these young children we evaluate our experience and results.

PATIENTS AND METHODS

From 1990 to 2001 preventive total thyroidectomy was performed in 13 MEN-2a gene carriers (4 boys and 9 girls; median age 7 (4-14) years). Preoperative assessment, surgical procedure, pathological examination, postoperative complications and treatment results were studied.

RESULTS

Surgery existed of a total thyroidectomy alone (n=3) in children with normal basal calcitonin and in combination with tracheo-esophageal exploration (n=6) or central compartment dissection (n=4) in case of abnormal calcitonin levels. Eight children presented with medullary thyroid cancer (MTC), three (median: 5 (4-12) years) with microscopic MTC and five (median 6 (4-14) years) with frank invasive MTC. Four of these five patients were younger than 6 years. Except for long-lasting hypoparathyroidism in one patient there were no complications. At a median follow-up of 6.5 years all patients are disease free.

CONCLUSION

MTC in RET mutated MEN-2a gene carriers in childhood are found at the age of 4 years. Therefore, DNA testing should be done preferably before that age. Preventive surgery can be performed safely at that age and may be limited to total thyroidectomy when baseline calcitonin levels are normal.

Multiple endocrine neoplasia type 2a (MEN2a): a call for psycho-social research

This paper summarizes what is known about the diagnosis, treatment, and follow-care of people with the inherited disorder multiple endocrine neoplasia type 2a (MEN2a). Several databases were searched throughout the year 2000, including MEDLINE, CINAHL, CancerLit, PsychINFO, and Dissertation Abstracts International. MEN2a is a complex disease involving cancer care and control by surgery, health maintenance, and life-long observation of gene mutation carriers. Genetic testing is the standard of care, prophylactic surgery is recommended during directive counseling, and life-long surveillance is encouraged for people with MEN2a. A substantial body of scientific literature describes morbidity and mortality outcomes of disease treatment, and the monitoring of multiple organ systems. Research is scant concerning the psychological consequences and social impact of the MEN2a diagnosis, treatment, and follow-up. Nearly all that is known from a psycho-social perspective comes from data in The Netherlands. Little is known of the psychological responses to and social consequences of genetic predisposition testing, prophylactic and curative surgery, and life-long surveillance. Psycho-social research is essential to provide comprehensive care for patients and family members with this disorder and it is necessary to guide the development of risk management strategies for patients with this inherited cancer syndrome. Since MEN2a has been labeled a prototype for medical genetics, information on MEN2a patient experiences may be relevant to the care of individuals with other inherited cancer syndromes.

Cancer of the thyroid gland in infants and children

Carcinoma of the thyroid gland is unusual in children and represents only about 3% of pediatric malignancies. Surgical management is the principal method of treatment, but there is considerable controversy regarding exactly how much of the thyroid gland should be removed for adequate treatment. There also is controversy regarding the use of fine-needle aspiration (FNA) in the evaluation of potentially neoplastic thyroid lesions. In this report, the pertinent literature is reviewed regarding these issues. Moreover, this report will discuss recent discoveries that have elucidated some of the molecular biological events responsible for the development of thyroid cancer.

Multiple endocrine neoplasia type iia: report of a family with a study of three generations in qatar

OBJECTIVE

To study the pattern of multiple endocrine neoplasia type IIA (MEN IIA) and describe the clinical features and results of genetic testing and treatment in 21 members of the first reported family with MEN IIA in Qatar.

METHODS

After identification of the proband, we screened all her family members (21 members) with genetic testing for the RET proto-oncogene mutation. Those subjects with the mutation were further assessed for pheochromocytoma by measurement of the 24-hour urinary vanillylmandelic acid, metanephrines, and catecholamines, and those with high levels underwent a metaiodobenzylguanidine scan and adrenalectomy. The serum calcium was measured in a effort to detect hyperparathyroidism. Those family members who had the mutation and were eligible for surgical treatment underwent total thyroidectomy and central compartment dissection. In those patients with high postoperative calcitonin levels, residual disease was sought with radiologic imaging, and follow-up was done with pentagastrin stimulation tests.

RESULTS

Of the 21 family members screened, 10 had the RET proto-oncogene mutation (codon 634, TGC->GGC) (5 females and 5 males; 6 adults and 4 children). All the adults had bilateral medullary thyroid carcinoma (MTC); four of them had lymph node metastatic lesions, and one had metastatic involvement of the liver. Two adults had pheochromocytomas. Two family members were reported to have parathyroid hyperplasia, although both were normocalcemic.

CONCLUSION

This family with MEN IIA showed classic mendelian autosomal dominant inheritance. All adult patients had MTC, two had pheochromocytomas, and two had parathyroid hyperplasia. Although one child had a high stimulated calcitonin level, the histopathologic findings were normal; another child with high stimulated calcitonin levels showed C-cell hyperplasia on histopathologic examination.

Multiple endocrine neoplasia type 2B — genetic basis and clinical expression

Multiple endocrine neoplasia (MEN) type 2B is a heritable endocrine disorder characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, multiple mucosal neuromas, and a marfanoid habitus. Intestinal ganglioneuromatosis, corneal nerve thickening and skeletal abnormalities are also often present. The disease is inherited in an autosomal dominant fashion and is caused by a single mutation in the RET proto-oncogene, with a methionine to threonine substitution at codon 918. The MTC in MEN 2B presents at an earlier age and tends to be more aggressive than the MTC in MEN 2A. It is multicentric and bilateral and occurs as young as age 3, with early lymph node metastases. Pheochromocytoma is also often bilateral but is rarely malignant. If pheochromocytoma is detected, adrenalectomy should precede thyroidectomy to avoid intraoperative catecholamine crisis. Patients at risk for MEN 2B should undergo genetic screening in infancy. Total thyroidectomy should be performed on all patients positive for RET mutations even prior to the onset of clinical symptoms.

Multiple endocrine neoplasias

Multiple endocrine neoplasia type 1 (MEN 1), and the multiple endocrine neoplasia type 2 syndromes (MEN 2A, MEN 2B, and familial non-MEN medullary thyroid carcinoma [FMTC]) encompass a wide range of endocrine problems, but arise from only two genes: the MEN 1 tumor suppressor gene and the RET proto-oncogene. MEN 1 is characterized by parathyroid hyperplasia, pancreaticoduodenal neuroendocrine tumors (PNTs), and pituitary adenomas. Surgery is the principal treatment modality for hyperparathyroidism and PNTs, but questions still remain concerning the timing and extent of surgery for PNTs. The MEN 2 syndromes are characterized by complete penetrance of medullary thyroid cancer. The MEN 2 syndromes differ in their variable expression of hyperparathyroidism, pheochromocytomas, and other clinical features. Genetic testing for mutations in the RET gene has revolutionized treatment by enabling thyroidectomies before significant disease occurs.

Predictive DNA testing for multiple endocrine neoplasia 2: a therapeutic challenge of prophylactic thyroidectomy in very young children

BACKGROUND

Patients with multiple endocrine neoplasia (MEN) type 2 are at risk for early medullary thyroid carcinoma (MTC). Recently, the cloning of the ret oncogene has made it possible to identify patients at risk for MEN 2 syndrome with a high degree of reliability before presenting any symptoms.

METHODS

Children of families with MEN 2 were screened genetically if one of the parents was a known gene carrier of the RET proto-oncogene. If they were carriers, thyroidectomy was performed.

RESULTS

The authors report five children with MEN 2 who underwent prophylactic thyroidectomy irrespective of the results of calcitonin screening tests after genetic screening had shown that they were carrier of the RET proto-oncogene. Apart from a temporary hypocalcemia in one, the operations were uneventful. Pathology results showed MTC in three children of one family with MEN 2A at age 2, 3, and 6 years. In two families with MEN 2B the thyroidectomy specimen showed bilateral MTC in a 1-year-old and a 3-year-old child.

CONCLUSIONS

These findings show that MTC occurs at very young age in children with MEN 2. The authors advocate performing prophylactic thyroidectomy in the first year of life in children with MEN 2B and at age 2 years in children with MEN 2A to obtain an optimal cure rate.

Ret-proto-oncogene analysis in medullary thyroid carcinoma

INTRODUCTION

Medullary carcinoma of the thyroid (MTC) is a rare tumour which occurs in both sporadic and hereditary forms. Mutations of the RET proto-oncogene have been identified in hereditary forms. The aim of our study was to confirm or exclude familial disease by examining for germline mutations in the RET proto-oncogene in patients with medullary thyroid carcinoma.

METHODS

Nine patients with medullary thyroid carcinoma and 4 of their children were studied. Peripheral blood was used to examine for mutations in the RET proto-oncogene. When this was not available, archival thyroid tissue was used.

RESULTS

Seven patients had clinically sporadic tumours confirmed by mutational analysis of RET. Four children were at risk of being carriers of a mutated gene, as their fathers had histologically proven MTC and had tested positive for the mutation at codon 618 on exon 10 of the RET proto-oncogene. Three of these children carried the 618 mutation. To date, 2 have had a prophylactic thyroidectomy, the pathology of which revealed C-cell hyperplasia. One child had familial disease excluded by mutational analysis. One patient had a clinical diagnosis of MEN2B confirmed by detection of the 918 mutation on exon 16 of the RET proto-oncogene.

CONCLUSIONS

RET proto-oncogene analysis is a reliable method of differentiating familial from sporadic MTC. Mutational information determines which family members of affected kindreds are at risk of developing the disease and can be used to affect clinical management.

Multiple endocrine neoplasia type II and familial medullary thyroid carcinoma. Impact of genetic screening on management

The identification of ret protooncogene mutations in MEN-II and Hirschsprung disease has not only improved the clinical management of these genetic conditions but has also provided important information regarding mechanisms of transformation and neural crest development. An indication of how neural-crest cells migrate during embryonic life and the key processes involved in their differentiation now seems within reach. The continued pace of scientific discovery suggests that our understanding of and ability to prevent or treat hereditary and sporadic forms of MTC will continue to improve.

Germline mutations of the RET proto-oncogene in pedigree with MEN type 2A: DNA analysis and its implications for pediatric surgery

To assess the feasibility of screening for multiple endocrine neoplasia type 2A (MEN 2A), the authors used DNA sequence analysis to evaluate the RET proto-oncogene in a kindred with MEN 2A. The kindred consisted of 95 members (1 to 79 years of age) and their spouses, and spanned five generations. Genomic DNA was extracted from peripheral blood lymphocytes or lymphoblastoid cell lines established from the family members, and the RET gene was amplified by polymerase chain reaction (PCR) using RET-specific primers (10q 11.2) and was sequenced. Periodic endocrine screening also was performed, by measuring the plasma calcitonin concentration after provocation with pentagastrin (0.5 microgram/kg intravenously) to assess its reliability for detecting the associated neoplasms. Nineteen patients were confirmed to have MEN 2A by medical records or the screening program. The DNA sequence of the PCR products from clinically established MEN 2A patients showed a mutation at codon 634 (TGC-->CGC) that resulted in an amino acid change from cysteine to arginine. Endocrine screening tests showed that six other family members had a mutated RET protooncogene. DNA sequencing can detect high-risk cases at a preclinical stage of the disease. The establishment of mutated MEN 2A gene carriers allows pediatric surgeons to consider total thyroidectomy at a very early stage of neoplasm development (C-cell hyperplasia) or even prophylactically.

Application of genetic screening information to the management of medullary thyroid carcinoma and multiple endocrine neoplasia type 2

Application of RET proto-oncogene mutation analysis to the clinical management of MEN 2 and FMTC has simplified and enhanced the power of earlier used screening and treatment efforts for hereditary MTC. The approaches outlined herein are cost-effective, have improved diagnostic accuracy, and hold the promise of improved cure rates for this neoplasm. Further studies to elucidate the mechanism by which these activating mutations cause transformation may lead to other strategies for prevention or treatment of this neoplasm.

Medullary thyroid carcinoma in children with multiple endocrine neoplasia types 2A and 2B

Recently it has become possible to identify persons who have multiple endocrine neoplasia (MEN) syndrome types 2A and 2B based on the presence of missense mutations in the RET protooncogene. Kindred members who have inherited these syndromes can be identified before clinical or biochemical evidence of medullary thyroid carcinoma (MTC) develops, the malignancy that occurs in all affected patients. It is not known whether prophylactic removal of the thyroid gland early in childhood, based on a positive genetic test result, has a better clinical outcome than that associated with thyroidectomy after MTC is diagnosed clinically or biochemically. The authors' goal was to determine the long-term outcome for patients with MEN 2A and 2B who had thyroidectomy for MTC during childhood. These results were compared with those of patients who had prophylactic removal of the thyroid gland after the genetic diagnosis of MEN 2A was established. The hospital records of 49 children with MEN 2A or 2B were reviewed. Each patient had thyroidectomy for MTC before 16 years of age. The mean age at the time of operation was 10 years, and the mean follow-up period for those who had surgery before the availability of direct DNA genetic testing was 9.8 years. The indications for surgery included an elevated basal or stimulated plasma calcitonin level, a positive genetic test result, a thyroid mass, family history of MTC, or a phenotype diagnostic of MEN 2B. All children for whom the diagnosis of MEN 2A was established by direct genetic testing had thyroidectomy within the last 2 years. Of the 11 patients with MEN 2B who underwent thyroidectomy during childhood, 10 had MTC, and only 3 (27%) remain free of disease after the mean follow-up period of 11 years. One patient died, and seven are alive with persistent MTC. Among the 24 patients with MEN 2A who had their thyroid glands removed because of a family history of MTC or because of biochemical evidence of the disease, 5 (21%) have persistent or recurrent MTC after the mean follow-up period of 9.3 years. In four of these, the MTC was confined to the thyroid gland at the time of thyroidectomy. Of the 14 children who had thyroidectomy based on direct DNA testing, MTC was present in 11. Only four had elevated levels of stimulated plasma calcitonin before surgery. None had lymph node metastasis or surgical complications. The authors conclude that a significant number of patients with MEN 2A or 2B who undergo thyroidectomy in childhood for MTC have persistent or recurrent disease long-term. The genetic diagnosis of patients with these syndromes may allow for prophylactic surgery before the development of biochemical or clinical evidence of MTC. This approach is safe, but longer clinical follow-up will be necessary to confirm that MTC has been cured.

Clinical use of molecular information in the management of multiple endocrine neoplasia type 2A

One hundred and ninety-seven members of 28 kindreds with multiple endocrine neoplasia type 2A (MEN 2A) were screened for RET proto-oncogene exon 10 and 11 mutations. Seventy-one known affected individuals had mutations of codons 609, 618, 620 or 634, whereas 53 unaffected individuals had no abnormalities. Nineteen out of 54 individuals of unknown status, mostly children, had RET mutations. Four of these children had thyroidectomy based on this analysis and were found to have C-cell abnormalities. We identified one false negative mutation analysis because of a codon 691 polymorphism. We conclude that RET mutational analysis is a cost-effective and accurate method for determination of gene carrier status in MEN 2A.

Medullary thyroid carcinoma: recent advances and management update

Medullary thyroid carcinoma (MTC) is a malignancy of the thyroid C-cells that comprises 5-10% of all thyroid cancers. MTC occurs in both sporadic and familial forms, the latter making up 25% of all MTCs and being comprised of three distinct syndromes--multiple endocrine neoplasia type 2A (MEN 2A), multiple endocrine neoplasia type 2B (MEN 2B), and familial medullary thyroid carcinoma (FMTC). To date, screening for MTC has been performed using the pentagastrin stimulation test, which is a provocative test for calcitonin release. Germline mutations in the RET protooncogene have been identified in families manifesting these syndromes and genetic screening of individuals at risk of one of these syndromes has become integral to their clinical management. The majority of the mutations associated with MEN 2A and FMTC are tightly clustered in a cysteine-rich region of the RET receptor. A single mutation associated with MEN 2B is in the the tyrosine kinase domain of the RET receptor. Somatic mutations have been identified in the tumor tissue of individuals with sporadic MTC and may prove to be helpful markers in discerning the hereditary or sporadic nature of the MTC. There is general agreement that the primary operation for MTC should include total thyroidectomy and central neck lymph node clearance. The role of microdissection for recurrent disease awaits longitudinal evaluation. External radiotherapy, radionuclide therapy, and chemotherapy may have a role in palliation, but have not been proven to have a curative value. Prognostic factors are discussed.

Total thyroidectomy in the treatment of thyroid carcinoma in childhood

Between 1974 and 1993 ten girls and six boys aged 6-16 years underwent total thyroidectomy, with therapeutic selective neck dissection in six patients. All were treated after operation with radioactive iodine (131I) for ablation of thyroid tissue remnants. Papillary carcinoma occurred in ten patients, follicular carcinoma in two and medullary thyroid lesions in four. The patients were followed for a median of 11.5 (range 1-20) years with regular determinations of serum thyroglobulin levels and 131I whole-body scanning when indicated. Only one patient had a slight increase in thyroglobulin levels without evidence of disease on further screening. In children with medullary lesions the serum levels of basal and pentagastrin-stimulated calcitonin remained normal. Currently all patients are alive and without disease. Hypocalcaemia lasting for more than 1 year was observed in one patient. Recurrent nerves were not injured accidentally, but because of tumour invasion two of 32 recurrent nerves had to be sacrificed. This surgical approach is safe and well tolerated in children.

RET proto-oncogene mutations in multiple endocrine neoplasia type 2 and medullary thyroid carcinoma

The identification of RET proto-oncogene mutations in patients with MEN2 2 years ago was a watershed event in the management of this genetic cancer syndrome. The identification of a finite number of mutations that together causes more than 95% of hereditary and 15-25% of sporadic MTC has made it possible to develop simple and definitive tests to screen individuals at risk for this tumour syndrome. The impact of this technology is enormous. It is now possible to reassure 50% of family members at risk that they, and their children, do not have to worry about developing MTC. In the other 50% who are gene carriers, it is now possible to approach clinical management with greater certainty and plot strategies that are likely to result in a greater percentage of curative therapy. It seems likely that this technology will also have an impact on the management of sporadic MTC, although it is still too early to define a specific role for mutational analysis in these patients, except to exclude hereditary disease. The identification of specific mutations causative for MTC makes it possible to conceive future strategies for the treatment or prevention of MTC and to further extend the impact of these exciting findings.

Prediction of affected MEN2A gene carriers by DNA linkage analysis for early total thyroidectomy: a progress in clinical screening program for children with hereditary cancer syndrome

The gene predisposing to multiple endocrine neoplasia type 2A (MEN 2A) has been assigned to chromosome 10, and affected gene carriers can be identified before the development of associated malignancy in some informative families. We applied these advances in gene mapping to clinical screening for possible pediatric surgery. A family with MEN 2A, consisting of 88 members and their spouses, was studied to test the reliability of the provocation of plasma calcitonin with pentagastrin and the possibility of DNA diagnosis of mutated gene carriers with DNA probes closely linked to the MEN2A gene including RBP3 and FNRB genes. Nineteen of the 88 were diagnosed as MEN 2A carriers. Twelve of them were treated surgically and the others died of medullay thyroid carcinoma (MTC) or pheochromocytoma. A strikingly sensitive response of calcitonin was observed in all those with MTC. The genotypes cosegregating with the abnormal allele at MEN2A in this family could be deduced from clinically established affected members. The early detection of gene carriers allows us to concentrate our screening efforts on children at high risk and to release non gene carriers from repeated unnecessary testing. MEN2A is one of the first cancer syndromes for which DNA screening permits early detection of members at high risk.

Multiple endocrine syndrome type IIb in early childhood

A 3-week-old girl who was born with club feet had signs of failure to thrive. On physical examination the child appeared normal; she had no abnormalities in the mucous membranes of the mouth, the eyelids, or in the neck, and her other systems, including heart, chest, abdomen, and neurologic systems, were clinically normal. Radiologically, the gastrointestinal tract was normal, but rectal biopsy showed neuromas. Her serum calcitonin level was measured both at basal and after pentagastrin stimulation at 5 weeks of age and found to be high, but whether it was consistent with the normal level at this early age or was caused by medullary thyroid carcinoma was not clear. At 3 months, the corneal nerves of both eyes were examined and showed considerable thickening, and multiple endocrine syndrome type IIb was suspected. The serum calcitonin level at 8 and 14 months was increased. A total thyroidectomy was done, and C-cell nodular hyperplasia and adenomatosis was found in the isthmus. The postoperative serum calcitonin level decreased to low normal and did not increase after pentagastrin stimulation. To the authors' knowledge, this case represents the youngest patient diagnosed with multiple endocrine syndrome type IIb in the absence of family history of the disease.

The impact of gene mapping techniques on the management of multiple endocrine neoplasia type 2

There has been sustained progress toward the identification of the gene for multiple endocrine neoplasia type 2. Closely linked and flanking DNA markers have been identified, and it is now possible to assign gene carrier status in informative families at risk with a >90% certainty by the use of molecular genetic techniques. Application of-these techniques, however, requires an understanding of their current limitations and caution in their use of clinical decision making.

The natural history of multiple endocrine neoplasia type 2A--a clinical analysis

The records of 18 patients with multiple endocrine neoplasia (MEN) type 2A in a family consisting of 87 members in 5 generations, were reviewed with respect to age at onset and length of survival in a study of the natural history of this syndrome. Of these 18 patients, 8 were alive following surgical treatment, while 10 had died without treatment. The clinical onset of medullary thyroid carcinoma was noticed as a nodule in the neck at between 17 and 34 years of age (mean 24 years); the onset of pheochromocytoma was characterized by palpitation, hypertensive attacks or recurrent headache at between 17 and 42 years of age (mean 27 years); and death occurred in 10 patients at between 23 and 67 years of age (mean 40.6 years). This information on the age at onset of individual clinical manifestations, and on the length of survival of gene carriers, may be useful for clinicians who are asked to assess the risk of the development of this syndrome in a genetically predisposed asymptomatic individual, because screening tests are often refused by members of Japanese families with MEN type 2A.

Multiple endocrine neoplasia type II B with symptoms suggesting Hirschsprung's disease: a case report

A 3-year-old child was referred with a tentative diagnosis of Hirschsprung's disease because of life-long constipation and "megacolon" demonstrated radiographically. Our rectal biopsy revealed hyperganglionosis suggestive of multiple endocrine neoplasia (MEN) type II B. This, in addition to an elevated serum calcitonin level, prompted surgical removal of her thyroid, which appeared grossly normal but on sectioning, contained a medullary carcinoma in each lobe. She remains disease-free 5 years later. Gastrointestinal symptoms are a significant component of the MEN type II B syndrome, and often antedate the full phenotypic expression of the syndrome and the development of potentially lethal endocrine neoplasms. On the basis of this experience, it is recommended that MEN II B be included in the differential diagnosis of chronic constipation.

Provocative testing for occult medullary carcinoma of the thyroid: findings in seven children with multiple endocrine neoplasia type IIa

A rise in the serum calcitonin (CT) following provocative testing has facilitated making the diagnosis of occult medullary carcinoma of the thyroid (MCT) or C cell hyperplasia (CCH) in asymptomatic children of kindred with multiple endocrine neoplasia (MEN) type IIa. Findings were reviewed for seven children varying in age from 3 to 16 years screened at our institution between 1976 and 1986. Three had elevated basal calcitonin (S-CT). Six had significant elevation of calcitonin (delta-CT) after stimulation. Total thyroidectomy was performed in all seven. Five had MCT with bilobar involvement in three. CCH was present in all five. Two patients had no gross, microscopic, or immunohistochemical evidence of MCT or CCH. One of three had an elevated S-CT. The other had a significant delta-CT. All patients have normal postoperative S-CT and delta-CT. Our experience indicates the importance of beginning stimulation tests of affected kindred at less than 3 years of age. It appears, however, that neither elevated S-CT or positive delta-CT are perfect predictors of parafollicular cell pathology. Solitary parathyroid enlargement, second thyroid malignancy, and branchial pouch anomalies may occur with MEN IIa. One patient with MCT had a focus of papillary carcinoma. One patient with primary hyperparathyroidism had a solitary enlarged parathyroid adenoma. Additional findings were the presence of nodules of ectopic thymus in close association with the thyroid gland in three patients.