Extensive mutation scanning of RET in sporadic medullary thyroid carcinoma and of RET and VHL in sporadic pheochromocytoma reveals involvement of these genes in only a minority of cases

Sporadic medullary thyroid carcinoma (MTC) and pheochromocytoma (PC) have been reported to be associated with some specific RET gene mutations. To assess the role of RET in the development of MTC and PC, we screened 14 sporadic MTC, two MTC-derived cell lines, and 5 sporatic PC cases of RET mutations by a systematic analysis of the whole coding sequence, including all intron-exon junctions. In only 6 of the 14 sporadic MTC we were able to detect a RET mutation. Apart from the MET918-->Thr mutation in 5 of the MTC cases, we found a 3-bp deletion in exon 11, only present in the tumor, in another case. Analysis of 2 cell lines revealed the Met918-->Thr mutation in 1 and a Cys634-->Trp mutation in the other cell line. A possible somatic nature of these mutations could not be confirmed because in neither case was constitutive DNA available. We conclude that a large proportion of sporadic MTC must be due to mutations in an unidentified gene(s) other than RET. In none of the sporadic PC cases was a RET mutation found. As PC is a frequent complication in families suffering from von Hippel Lindau disease, for which mutations of the VHL gene are responsible, we also screened the 5 sporadic PC cases for VHL mutations. This revealed a Gly164-->Ser mutation in a single specimen. Thus, in PC, a large majority of tumors are due to mutations in an unidentified gene(s) other than RET and VHL.

RET mutation screening in familial cutaneous lichen amyloidosis and in skin amyloidosis associated with multiple endocrine neoplasia

In several families, multiple endocrine neoplasia type 2A (MEN 2A) has been found in association with cutaneous lichen amyloidosis. It has been debated, however, whether the skin amyloidosis found in MEN 2A families, localized exclusively in the interscapular area, represents the same anomaly as that found in autosomal dominant familial cutaneous lichen amyloidosis, which is more generalized. We screened two MEN 2A families with associated skin amyloidosis for germline mutations in the RET gene responsible for the MEN 2A cancer syndrome, and found the same mutation characteristic of MEN 2A in both families. We also screened probands from three pedigrees with familial cutaneous lichen amyloidosis for RET mutations. In none of the RET coding and flanking intronic sequences was a mutation detected. This most probably indicates that skin amyloidosis found in some MEN 2A families and familial cutaneous lichen amyloidosis are different conditions. Consequently, patients with apparent familial cutaneous lichen amyloidosis do not appear to be at risk for MEN 2A.

Expression pattern of the von Hippel-Lindau protein in human tissues

von Hippel-Lindau (VHL) disease is an autosomal dominant inherited disorder characterized by extensively vascularized tumors and cysts in specific organs. The VHL gene product plays a critical role in the regulation of transcription elongation by RNA polymerase II. To provide insight into which cells the VHL protein is expressed, we performed immunohistochemistry on human tissue and tumors. The VHL protein was widely expressed in normal human tissue. The cellular distribution of the protein was confined to the cytoplasm of specific cell types. High levels of expression of the protein were observed in neural tissue, especially in Purkinje cells, Golgi type II cells, and dentate nucleus of the cerebellum, pontine nuclei, the inferior olivary nucleus of the medulla oblongata, orthosympathetic ganglia, myenteric, and submucous plexus of the colon. In the other target organs of the VHL disease, high expression was observed in the renal tubule system, the exocrine pancreas, the adrenal cortex, and liver parenchyma. The VHL protein was also expressed in organs not at risk for the disease. The eosinophilic cells of the pituitary gland, epithelial cells of the follicles of the thyroid, epithelial cells of the intestines, bile ducts, and bronchial epithelia showed strong VHL immunoreactivity. Immunohistochemistry did not facilitate the discrimination of tumors obtained from VHL patients or tumors unrelated to the VHL disease. Renal cell carcinomas, hemangioblastomas, and pheochromocytomas, either VHL-related or sporadic, demonstrated positive staining for the VHL protein, which suggests that the antibody also recognizes the mutated VHL protein. The present study suggests a role for the VHL gene that goes beyond the organs involved in the disease. The recognition of cell-specific VHL expression provides a framework for further studies to elucidate the normal function of the VHL gene and to determine its role in specific cell types.

Cortisol secretory patterns in Cushing's disease and response to cyproheptadine treatment

To investigate whether cortisol secretory patterns are associated with a response to cyproheptadine treatment in Cushing's disease, we studied two patients with a hyperpulsatile pattern and one patient with a hypopulsatile pattern before and during chronic cyproheptadine therapy (24 mg daily). In the two patients with a hyperpulsatile cortisol secretory pattern, pituitary magnetic resonance imaging with gadolinium did not reveal a pituitary adenoma, whereas in the patient with a hypopulsatile cortisol secretory pattern, a microadenoma was identified. Plasma cortisol levels were measured every 30 min for 24 h. In the two patients with a hyperpulsatile cortisol secretory pattern, chronic treatment with cyproheptadine resulted in sustained clinical and biochemical improvement and normalization of the median of absolute and relative increments in cortisol spikes. In the patient with a hypopulsatile cortisol secretory pattern, only a reduction of cortisol spikes was noticed during treatment. These results suggest that patients with Cushing's disease who are characterized by a hyperpulsatile cortisol secretory pattern and in whom no pituitary lesion can be identified by magnetic resonance imaging, cyproheptadine treatment may be useful.

Psychosocial consequences of DNA analysis for MEN type 2

Multiple endocrine neoplasia type 2 (MEN-2) is characterized by medullary thyroid carcinoma in combination with pheochromocytomas and, sometimes, parathyroid adenomas. Since 1993, the psychosocial implications of DNA analysis for MEN-2 have been studied in the Netherlands. This article summarizes the first results of that study. Individuals who applied for DNA analysis cited the need to reduce uncertainty as the major reason for wanting the test. An unfavorable test outcome resulted in anxiety and depression but also relief. Immediate preventive treatment was preferred to continued periodic screening. Carriers were preoccupied with disease-related complaints, and identified with other carriers and MEN-2 patients. A favorable test led, in most applicants and partners, to both relief and worry. Some noncarriers felt guilty and isolated from their families. One year after counseling, participants reported fewer psychosomatic complaints.

Mutation analysis of the RET proto-oncogene in Dutch families with MEN 2A, MEN 2B and FMTC: two novel mutations and one de novo mutation for MEN 2A

Hereditary C-cell carcinoma is encountered in multiple endocrine neoplasia type 2A (MEN 2A), MEN 2B, and familial medullary thyroid carcinoma (FMTC). Mutations of the RET proto-oncogene are associated with all three diseases. To obtain an insight into the molecular heterogeneity of MEN 2 syndromes and FMTC in the Netherlands, probands of 20 MEN 2A families, two FMTC families, and seven MEN 2B families were analyzed by the polymerase chain reaction (PCR), DNA sequencing, and restriction enzyme digestion for abnormalities in the RET proto-oncogene. RET mutations were found in all cases. All MEN 2A families had a mutation involving one of five cysteine codons in exons 10 and 11 of RET. Two novel dinucleotide mutations and a de novo mutation were found. Both FMTC families had a mutation of the Cys at codon 618. All MEN 2B probands carried a Met to Thr mutation in exon 16. All mutations could be confirmed by restriction enzyme digestion of PCR amplicons. Identification of the RET mutation in the Dutch population with hereditary C-cell carcinoma facilitates genetic testing for families or individuals at risk for MEN 2A, FMTC, and MEN 2B.

From medical history and biochemical tests to presymptomatic treatment in a large MEN 2A family

An extensive study was published in 1959 in the Netherlands on a large family, which initially attracted attention because of a family history of attacks of shaking. Clinical investigation revealed phaeochromocytomas in four family members. In 1975, the family was identified to be a MEN 2A family, and since then, the members were examined annually using measurement of catecholamine metabolites in 24-h excreted urine and C-cell stimulation tests. In 1993, the RET proto-oncogene on chromosome 10q11 was found to be associated with MEN 2A and a specific mutation in this gene was identified in the family. In this family, 32 MEN 2A patients were detected. Since screening started in 1975, no patient died of phaeochromocytoma; however, two patients died of metastasized medullary thyroid carcinoma (MTC) (mean age 46 years). Twelve patients were operated on for phaeochromocytoma, and 13 for MTC. The results of DNA-analysis revealed the failures of the biochemical tests to identify affected family members. Six disease gene carriers with normal C-cell stimulation test results appeared to have small multifocal MTCs. Two carriers with normal excretion levels of catecholamines had a small phaeochromocytoma. DNA-analysis enables the unambiguous diagnosis of MEN 2A gene carrier-ship, allowing presymptomatic surgery for MTC.

Genotype-phenotype correlation in multiple endocrine neoplasia type 2: report of the International RET Mutation Consortium

The International RET Mutation Consortium was first convened as part of the Fifth International Workshop on Multiple Endocrine Neoplasia, Stockholm, Sweden, in an attempt to analyse the relationship of RET mutation and disease phenotype in the autosomal dominantly inherited multiple endocrine neoplasia type 2 (MEN 2) syndromes. Out of 361 families studied, 41% had MEN 2A, 17.7% MEN 2B, 6.4% FMTC and the remaining subjects were unclassified. RET mutations were detected in 87.3% of families overall. Over 93% of MEN 2B families had the RET 918 ATG-->ACG mutation, while the most frequent mutation detected in MEN 2A families was cysteine codon 634 (87% of all mutations).

Pancreatic islet amyloid formation in patients with noninsulin-dependent diabetes mellitus. Implication for therapeutic strategy

Islet amyloid polypeptide (IAPP or amylin) is the main component of pancreatic islet amyloid found in the vast majority of patients with noninsulin-dependent (Type-2) diabetes mellitus (NIDDM). IAPP may also act as a hormone that antagonizes the effects of insulin on peripheral tissues, but the results with IAPP overproducing transgenic mice and other recent findings indicate that IAPP overproduction is unlikely to induce peripheral insulin resistance in NIDDM. However, IAPP may contribute to the progression of NIDDM by impairing beta-cell function via islet amyloid formation. This may be initiated by locally elevated IAPP concentrations, induced by insulin-resistance-associated beta-cell hyperactivity. In order to improve therapeutic results, we propose strategies to inhibit IAPP production and islet amyloid formation during the pathogenesis of NIDDM.

Von Hippel-Lindau syndrome

After a decade of intensive clinical and molecular genetic efforts the von Hippel-Lindau (VHL) gene was cloned in 1993. The open reading frame encodes the putative protein of 284 amino acids. A large number of different mutations have been identified so far, including single base mutations, deletions, rearrangements and more complex mutations. So far, in about 75% of the VHL families germline mutations were detected. Geno-phenotypic comparison has revealed specific mutations with distinct manifestation patterns. Not all of the 6 classical lesions (hemangioblastoma of the CNS, retinal angiomatosis, pancreatic cysts, renal cysts and carcinoma, pheochromocytoma and epididymal cystadenoma) are present in VHL families. Pedigrees with pheochromocytoma but without renal cancer in general have point mutations. These recent results provide insight in the pathogenesis of a multiorgan cancer susceptibility tumor suppressor gene and allow determination of carrier status.

Mitoxantrone in metastatic apudomas: a phase II study of the EORTC Gastro-Intestinal Cancer Cooperative Group

We performed a phase II study with mitoxantrone in patients with carcinoid tumours, islet cell tumours and medullary carcinomas of the thyroid. Thirty-five eligible patients received mitoxantrone 12 mg m-2 i.v. every 3 weeks. Among 18 previously untreated patients, three responded (17%, 95% CI = 4-41%); no responses were achieved in 17 previously treated patients. Of the 21 patients who had carcinoid tumours, 11 were previously untreated and two achieved a response (18%, 95% CI = 2-52%). Overall response rate was 9% (95% CI = 2-23%). At a median follow-up of 43 months, median overall survival was 16 months. The median survival of 21 patients with a normal alkaline phosphatase was 29 months and 9 months for 14 patients with elevated serum levels (P = 0.005). A similar observation was noticed for gamma-glutamyltransferase (P = 0.007). We concluded that mitoxantrone is not active in APUD tumours. Elevated alkaline phosphatase and gamma-glutamyltransferase are associated with a poor prognosis.

Clinical screening as compared with DNA analysis in families with multiple endocrine neoplasia type 2A

BACKGROUND

Multiple endocrine neoplasia type 2A (MEN-2A) is characterized by medullary thyroid carcinoma in combination with pheochromocytoma and sometimes parathyroid adenoma. Missense mutations in the RET proto-oncogene are associated with MEN-2A. Their detection by DNA analysis allows the identification of carriers of the gene, in whom the risk of medullary thyroid carcinoma is 100 percent. We compared the reliability of biochemical tests with that of DNA analysis in identifying carriers of the MEN2A gene.

METHODS

Starting in 1975, we screened 300 subjects in four large families with MEN-2A for expression of the disease, using measurements of plasma calcitonin after stimulation with pentagastrin or calcium and urinary excretion of catecholamines and catecholamine metabolites. We tested for carrier status by DNA analysis, including linkage analysis, and more recently by analysis of mutations in the RET gene.

RESULTS

Of 80 MEN2A gene carriers (in 61 of whom carrier status was proved by DNA analysis), 66 had abnormal plasma calcitonin values and medullary thyroid carcinoma. Fourteen young carriers had normal results of plasma calcitonin tests. In 8 of these 14, thyroidectomy revealed small foci of medullary thyroid carcinoma; the remaining 6 have not yet been operated on. Of the other 220 family members, 68 were found by DNA analysis not to carry the MEN2A gene. None of these 68 subjects had medullary thyroid carcinoma or pheochromocytoma; 6 had elevated plasma calcitonin concentrations and underwent thyroidectomy but had only C-cell hyperplasia.

CONCLUSIONS

Unlike biochemical tests, DNA analysis permits the unambiguous identification of MEN2A gene carriers.

Human islet amyloid polypeptide accumulates at similar sites in islets of transgenic mice and humans

The cellular mechanisms responsible for conversion of islet amyloid polypeptide (IAPP) into insoluble amyloid deposits in non-insulin-dependent diabetes mellitus (NIDDM) are not clear. Overexpression of IAPP and the amino acid sequence of human IAPP (hIAPP) have both been implicated. To examine factors involved in amyloid formation, transgenic mice expressing the hIAPP or rat IAPP (rIAPP) gene were generated. These mice had elevated plasma IAPP concentrations, and they were normoglycemic and normoinsulinemic. No amyloid deposits were detected by light microscopy. To examine the ultrastructure of islets, pancreatic tissue was studied from hIAPP and rIAPP transgenic mice and from age-matched control mice by immunoelectron microscopy. IAPP was immunolocalized in beta-cell secretory granules of all mice, and the COOH- and NH2-terminal flanking peptides of hIAPP were localized in beta-cell granules of hIAPP mice. Accumulations of nonfibrillar perivascular IAPP-immunoreactive material were found between capillaries and beta-cells in hIAPP transgenic mice but not in rIAPP transgenic or control mice. Similar nonfibrillar masses were identified in islets of an NIDDM patient. Secondary lysosomes in beta-cells and macrophages of hIAPP transgenic mice showed dense labeling for IAPP. We suggest that hIAPP is degraded more slowly than rIAPP or mouse IAPP by beta-cell lysosomes. Accumulations of IAPP in islet perivascular spaces may represent the early stages of islet amyloid formation.

An improved method for the determination of islet amyloid polypeptide levels in plasma

We describe an improved method for the determination of islet amyloid polypeptide (IAPP) levels in plasma. Plasma is first extracted with acid-acetone, followed by a specific and sensitive radioimmunoassay (RIA) for IAPP using rabbit-anti-human-IAPP serum. Recovery of synthetic IAPP from plasma was 82 +/- 6% (n = 16). Standard samples, prepared in 'hormone-free' serum, were also extracted with acid-acetone. Displacement curves of serially diluted acid-acetone extracted plasma samples were parallel to the standard curve. The lower detection limit of the RIA was 2.3 +/- 0.1 fmol/sample (n = 5). Intra-assay variations for IAPP concentrations of 4, 17 and 32 pM were 16.3% (n = 10), 9.2% (n = 10) and 6.2% (n = 10); interassay variations were 35.9% (n = 14), 19.9% (n = 15) and 15.4% (n = 15), respectively. Non-stimulated IAPP levels ranged from 2.4 to 12 pM (mean 6 +/- 4 pM, n = 10) in healthy control subjects. IAPP was not detectable in type 1 (insulin-dependent) diabetic patients before and after glucagon administration. In type 2 (non-insulin-dependent) diabetic patients basal levels ranged from 2.2 to 14.5 pM and glucagon-stimulated levels ranged from 2.2 to 38.9 pM. The increase in IAPP varied from 0 to 24.4 pM. The anti-human-IAPP serum had full cross-reactivity with rat IAPP (= mouse IAPP). Transgenic mice overexpressing the human IAPP gene showed elevated plasma IAPP levels as compared to (non-transgenic) control mice. It is concluded that the method presented for the determination of IAPP in plasma is reliable and easy to perform, yielding reproducible results.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly and hyperprolactinemia in a patient with polyostotic fibrous dysplasia: dynamic endocrine studies and treatment with the somatostatin analogue octreotide

Acromegaly and hyperprolactinemia have been described in association with polyostotic fibrous dysplasia; the pathogenetic mechanisms involved in the development of the endocrinopathies is unknown. We report a 26-year-old man with polyostotic fibrous dysplasia and hypersecretion of GH and PRL. Plasma GH, PRL, and insulin-like growth factor-I (IGF-I) were elevated. Glucose-non-suppressible plasma GH concentrations, GH responsiveness to TRH and GHRH, and GH suppression after a test-dose of somatostatin, octreotide, and bromocriptine were found. Plasma GHRH levels were within the normal range (< 25 ng/l). Computed tomography of the sella turcica and visual fields were normal. [111In-DTPA-D-Phe1]-octreotide scintigraphy were used to localize a possible tumor; no radioactivity was visualized at the site of the hypothalamus, the pituitary or elsewhere in the body but a considerable accumulation of radioactivity was found in the os frontalis. Therapy with octreotide by continuous sc infusion partially suppressed GH and IGF-I (and normalized PRL). The results suggest that hypersecretion of GH in our patient is not due to a GH-secreting pituitary tumor, eutopic or ectopic hypersecretion of GHRH or autonomous somatotroph function. The origin of the disease in this patient might be an abnormal hypothalamic regulation of somatotrophs and/or an alteration in the transmembrane signalling systems.

Molecular physiology of the islet amyloid polypeptide (IAPP)/amylin gene in man, rat, and transgenic mice

Islet amyloid polypeptide ("amylin") is the major protein component of amyloid deposits in pancreatic islets of type 2 (non-insulin-dependent) diabetic patients. Islet amyloid polypeptide consists of 37 amino acids, is co-produced and co-secreted with insulin from islet beta-cells, can act as a hormone in regulation of carbohydrate metabolism, and is implicated in the pathogenesis of islet amyloid formation and of type 2 diabetes mellitus. Rat islet amyloid polypeptide differs from human islet amyloid polypeptide particularly in the region of amino acids 25-28, which is important for amyloid fibril formation. In rat and mouse, diabetes-associated islet amyloid does not develop. To study the genetic organization and biosynthesis of islet amyloid polypeptide, we have isolated and analyzed the human and rat islet amyloid polypeptide gene and corresponding cDNAs. Both genes contain 3 exons, encoding precursor proteins of 89 amino acids and 93 amino acids, respectively. Apart from a putative signal sequence, these precursors contain amino- and carboxy-terminal flanking peptides in addition to the mature islet amyloid polypeptide. To understand regulation of islet amyloid polypeptide gene expression, we have identified several potential cis-acting transcriptional control elements that influence beta-cell-specific islet amyloid polypeptide gene expression. Using antisera raised against synthetic human islet amyloid polypeptide we developed a specific and sensitive radioimmunoassay to measure levels of islet amyloid polypeptide in plasma and tissue extracts. Also antisera raised against the flanking peptides will be used in studying human islet amyloid polypeptide biosynthesis. Elevated plasma islet amyloid polypeptide levels have been demonstrated in some diabetic, glucose-intolerant, and obese individuals, as well as in rodent models of diabetes and obesity. To examine the potential role of islet amyloid polypeptide overproduction in the pathogenesis of islet amyloid formation and type 2 diabetes, we generated transgenic mice that overproduce either the amyloidogenic human islet amyloid polypeptide or the nonamyloidogenic rat islet amyloid polypeptide in their islet beta-cells. Despite moderately to highly (up to 15-fold) elevated plasma islet amyloid polypeptide levels, no marked hyperglycemia, hyperinsulinemia or obesity was observed. This suggests that chronic overproduction of islet amyloid polypeptide "per se" does not cause insulin resistance. No islet amyloid deposits were detected in mice up to 63 weeks of age, but in every mouse producing human islet amyloid polypeptide (as in man), accumulation of islet amyloid polypeptide was observed in beta-cell lysosomal bodies. This may represent an initial phase in intracellular amyloid fibril formation.(ABSTRACT TRUNCATED AT 400 WORDS)

An avaII restriction fragment length polymorphism in the insulin-like growth factor II gene and the occurrence of smooth muscle tumors

To detect a previously described AvaII restriction fragment length polymorphism (RFLP) in the human insulin-like growth factor II (IGF-II) gene we used the polymerase chain reaction (PCR) and genomic sequencing. The RFLP is located in exon 9 of the IGF-II gene at nucleotide 820 (GenBank accession number X07868) as a C-->T transition. Digestion with AvaII reveals a two-allele polymorphism, an a allele in which the AvaII site is not present, and a b allele. In healthy Dutch persons (n = 26), the frequency of the a allele was 62%. A similar a allele frequency was found in groups of Japanese (53%, n = 65) and Chinese (54%, n = 84), while in a French group the frequency was significantly lower (25%, n = 52). In Dutch individuals that had developed benign (n = 11; all women) and malignant (n = 9; 2 women and 7 men) smooth muscle tumors, a significantly higher frequency of 83% for the a allele was found. Since there was no difference between the presence of the a and b alleles in normal and tumor tissue of the same individual, the higher a allele frequency was not due to mutation in the IGF-II gene or loss of heterozygosity. There was no correlation between the presence of the a allele and expression of the IGF-II gene. The data reveal a correlation between homozygosity for the a allele and the occurrence of smooth muscle tumors. Women homozygous for the IGF-II a allele are more prone to develop a leiomyoma than women who are heterozygous or homozygous for the b allele. Furthermore, in both women and men the risk for leiomyosarcomas seems to be higher in a allele homozygotes.

Plasma concentrations of islet amyloid polypeptide after glucagon administration in type 2 diabetic patients and non-diabetic subjects

Islet amyloid polypeptide (IAPP) is the main constituent of pancreatic islet amyloid, observed in the pancreases from patients with Type 2 diabetes mellitus. IAPP is synthesized by the pancreatic beta-cells. In order to study the secretion characteristics of IAPP in Type 2 diabetes mellitus, plasma IAPP was measured during a provocation test with glucagon in 33 Type 2 diabetic patients and 18 non-diabetic subjects. The median fasting IAPP level was 5.7 (range 1.1-13.1) pmol l-1 in the 27 patients treated with oral hypoglycaemic agents and 2.7 (1.9-5.9) in the 6 patients on insulin. In the non-diabetic group fasting IAPP was 5.7 (2.2-10.1). Six minutes after glucagon administration median IAPP rose to 9.4 (1.7-31.0) and 6.1 (5.1-10.2) in the respective diabetic groups, and to 16.8 (4.0-41.0) in the non-diabetic subjects (p << 0.05). The correlation coefficient between change in IAPP and change in C-peptide was 0.68 in the diabetic group. We conclude that intravenous administration of glucagon stimulates IAPP release from the beta-cell. This provocation test is easy to perform and can be used on a large scale in the study of IAPP secretion in Type 2 diabetes mellitus.

Strong promoter activity of human and rat islet amyloid polypeptide/amylin gene constructs in mouse beta cells (beta TC 3)

Islet amyloid polypeptide (IAPP)('amylin') is co-produced with insulin in pancreatic beta cells and is the formative polypeptide of pancreatic amyloid in patients with type 2 (non-insulin-dependent) diabetes mellitus. Islet amyloid and type 2 diabetes occur in man, but not in rat. To study transcription regulation of IAPP gene expression in man and rat, luciferase reporter constructs containing different portions of the upstream region of both IAPP genes were expressed in transfected cells. Both the human and the rat IAPP gene constructs revealed higher promoter activity in beta cells (particularly in beta TC3 cells) than in non-beta cells. In both IAPP genes potential transcription elements, with homology to insulin gene transcription elements, were identified. beta TC3 cells provide a good model system in which to study regulation of human and rat IAPP gene expression.

[Type II multiple endocrine neoplasms (MEN IIB): an unusual cause of constipation. A plea for early thyroidectomy]

We present a 5 year old girl who was diagnosed to have multiple endocrine neoplasia syndrome type IIB (MEN IIB). She presented with serious constipation and had the distinct features of MEN IIB. 100% of the patients with MEN IIB develop medullary thyreoïd carcinoma (MTC). MTC in MEN IIB is known to behave in a very aggressive way. Microscopically MTC was already present in this patient despite of normal calcitonin stimulation tests. Accordingly we plead for a more radical management relating to thyreoïdectomy in MEN IIB.