Sporadic primary hyperparathyroidism in the setting of multiple endocrine neoplasia type 1

Functioning glucagonoma associated with primary hyperparathyroidism: multiple endocrine neoplasia type 1 or incidental association?

BACKGROUND

Diagnosis of multiple endocrine neoplasia type 1 (MEN1) is commonly based on clinical criteria, and confirmed by genetic testing. In patients without known MEN1-related germline mutations, the possibility of a casual association between two or more endocrine tumors cannot be excluded and subsequent management may be difficult to plan. We describe a very uncommon case of functioning glucagonoma associated with primary hyperparathyroidism (pHPT) in which genetic testing failed to detect germline mutations of MEN-1 and other known genes responsible for MEN1.

CASE PRESENTATION

The patient, a 65-year old woman, had been suffering for more than 1 year from weakness, progressive weight loss, angular cheilitis, glossitis and, more recently, skin rashes on the perineum, perioral skin and groin folds. After multidisciplinary investigations, functioning glucagonoma and asymptomatic pHPT were diagnosed and, since family history was negative, sporadic MEN1 was suspected. However, genetic testing revealed neither MEN-1 nor other gene mutations responsible for rarer cases of MEN1 (CDKN1B/p27 and other cyclin-dependent kinase inhibitor genes CDKN1A/p15, CDKN2C/p18, CDKN2B/p21). The patient underwent distal splenopancreatectomy and at the 4-month follow-up she showed complete remission of symptoms. Six months later, a thyroid nodule, suspected to be a malignant neoplasia, and two hyperfunctioning parathyroid glands were detected respectively by ultrasound with fine needle aspiration cytology and 99mTc-sestamibi scan with SPECT acquisition. Total thyroidectomy was performed, whereas selective parathyroidectomy was preferred to a more extensive procedure because the diagnosis of MEN1 was not supported by genetic analysis and intraoperative intact parathyroid hormone had revealed "adenoma-like" kinetics after the second parathyroid resection. Thirty-nine and 25 months after respectively the first and the second operation, the patient is well and shows no signs or symptoms of recurrence.

CONCLUSIONS

Despite well-defined diagnostic criteria and guidelines, diagnosis of MEN1 can still be challenging. When diagnosis is doubtful, appropriate management may be difficult to establish.

Genetic analyses in familial isolated hyperparathyroidism: implication for clinical assessment and surgical management

OBJECTIVE

Familial isolated primary hyperparathyroidism (FIPH) can result from either incomplete expression of a syndromic form of familial primary hyperparathyroidism [multiple endocrine neoplasia type 1 (MEN 1), hyperparathyroidism-jaw tumour syndrome (HPT-JT) or familial hypocalciuric hypercalcaemia (FHH)] or still unrecognized causes. Design Genetic analyses of MEN1, HRPT2 and CASR genes in FIHP.

PATIENTS

Seven well-characterized Italian kindreds with FIHP, with negative clinical features for MEN 1, HPT-JT and FHH. The mean age (+/- SD) at diagnosis was 45 +/- 17 years (range 18-70 years) in the probands and 42 +/- 18 years (range 15-69 years) in the other affected subjects.

MEASUREMENTS

Direct sequencing of germline DNA of the MEN1, HRPT2 and CASR genes from probands. The region of interest was amplified in some family members.

RESULTS

Germline MEN1 mutations were detected in three kindreds. Multiglandular involvement was found in all but one affected subject belonging to the three kindreds with MEN1 mutations. In these patients persistence/relapse of the disease was observed unless an extensive parathyroidectomy (excision of 3(1)/(2) glands) had been performed, with the exception of one patient, who is currently normocalcaemic 168 months after excision of two glands. No mutations of MEN1, HRPT2 and CASR genes were identified in the remaining four families.

CONCLUSIONS

MEN1 genotyping appears worthwhile in FIHP families, as the finding of mutation(s) may predict multiglandular involvement and therefore have practical surgical implications, and prompt further investigation in the family, with the possibility of identifying new cases and beginning a programme of periodic surveillance for emergence of tumours in all carriers.

Primary hyperparathyroidism in multiple endocrine neoplasia type 1: individualized management with low recurrence rates

BACKGROUND

To evaluate the outcomes in different surgical modalities for primary hyperparathyroidism in multiple endocrine neoplasia type 1 (MEN1) patients, intraoperative findings from a single surgeon were studied to investigate a potentially improved modality of parathyroidectomy (PTx).

METHODS

All 22 patients had PTx by a single surgeon in the past 21 years. Three modalities of PTx were used, depending on the operative findings, after all parathyroids and the thymus were identified. If fewer than three glands were enlarged, selective removal of the enlarged glands with or without biopsy of a normal-appearing gland was performed (selective PTx); if all glands were enlarged, either a subtotal PTx leaving a 50-mg remnant in situ or a total PTx with autotransplantation (TPTx + AT) was performed.

RESULTS

There were 7 men and 15 women, aged 22 to 67 years (average, 43 years). Sixteen had familial and six had sporadic MEN1. They underwent 23 operations, including 11 selective PTx, 6 subtotal PTx, and 6 TPTx + AT. On follow-up for 1 to 19 years, only one patient (4.6%) had recurrent hyperparathyroidism 5.5 years after subtotal PTx. Others had either normocalcemia (n = 14; 63.6%) or hypocalcemia (n = 7; 31.8%). Those who had either a subtotal PTx or TPTx + AT had a significantly higher rate of postoperative hypocalcemia than those who had a selective PTx (9.9% vs. 54.5%; P = .032; Fisher's exact test).

CONCLUSIONS

Primary hyperparathyroidism in our MEN1 patients was less aggressive than that reported in the literature. Selective PTx according to the intraoperative findings achieved optimal outcomes.

Hereditary cancer syndromes of the skin

Hereditary cancer syndromes are a group of disorders characterized by a genetic susceptibility to the development of malignant tumors. Multiple cancers in the family or an abnormally early onset for the given cancer may suggest an underlying inherited predisposition. Awareness of their associated dermatologic manifestations can facilitate early detection of risk for neoplasms. This article provides an update on the clinical features, diagnostic criteria, and the use of genetic analysis in the detection of causative mutations of those hereditary cancer syndromes with cutaneous manifestations.

Deregulation of genetic pathways in neuroendocrine tumors

Complexity and redundancy of functional pathways controlled by the human genome explain that a single type of tumor can be induced by independant defective mutations in various genes that encode proteins acting in different parts of the cell physiology. Neuroendocrine tumors represent a powerful model for understanding such a complexity from the fact that at least six unrelated genetic syndromes have been characterized in the last decade which predispose to endocrine cell proliferation with variable penetrance and expressivity. Multiple Endocrine Neoplasia, von Hippel-Lindau. Carney and uncommonly Recklinghausen and Tuberous Sclerosis syndromes represent almost the whole panel of genetic diseases for which genes have been cloned and most of the functional knowledge has been collected. All the endocrine glands are concerned in these diseases, but the cellular pathways that are deregulated downstream from the deleterious mutations occurring in the genes of these autosomal dominant syndromes. might be related to each step of the cell life, from mitosis to DNA transcription, membrane receptor signalling and growth factor production, protein catabolism and extracellular matrix synthesis, and from transcription regulation to apoptosis and response to hypoxia and cellular stress. Here, we present an overview of genes involved in genetic predisposition to neuroendocrine tumors and highlight the complexity of pathways involved and the need of further studies focussing on genes involved in tumoral progression, most neuroendocrine tumors being benign at initial diagnosis but able to produce highly malignant cellular clones related to secondary genetic alterations or deregulation of growth factor production or cell cell adhesion processes.

Phenotype and phenocopy: the relationship between genotype and clinical phenotype in a single large family with multiple endocrine neoplasia type 1 (MEN 1)

BACKGROUND

The majority of reports describing the natural history and prognosis of multiple endocrine neoplasia type 1 (MEN 1) utilize phenotypic rather than molecular genetic criteria to establish a diagnosis of MEN 1.

OBJECTIVES AND PATIENTS

We sought to determine the spectrum of endocrine abnormality amongst 152 members (64 gene carriers and 88 noncarriers) of a large MEN 1 family in whom a determination of MEN 1 status had previously been made by phenotype screening. The predictive utility of both clinical and molecular screening techniques are described.

RESULTS

A novel IVS2-3 (C-G) MEN1 mutation was identified in affected members of this family. Seven (10%) of 71 individuals satisfying clinical diagnostic criteria for MEN 1 were found to be genetically negative (excluded by mutation analysis and haplotyping) for MEN 1. These cases of MEN 1 phenocopy comprised four cases of primary hyperparathyroidism, two 'nonsecretory' pituitary adenoma and one case of coincident prolactinoma and hyperparathyroidism. Three of the patients with hyperparathyroidism had previously required parathyroidectomy and each had achieved normocalcaemia following parathyroid resection. Predictive genetic testing prospectively identified three children with the MEN 1 genotype. Serum calcium was normal at the time of their initial molecular genetic diagnosis. In each case hyperparathyroidism subsequently developed during adolescence.

CONCLUSION

Multiple endocrine neoplasia type 1 phenocopy is an important differential diagnosis in patients exhibiting an multiple endocrine neoplasia type 1 phenotype. This is a relevant consideration, particularly when the diagnosis of multiple endocrine neoplasia type 1 is made using sensitive, but nonspecific, criteria such as mild hyperparathyroidism, pituitary micoadenoma, and hyperprolactinaemia. Confirmatory genetic testing should be undertaken to confirm clinical diagnoses of multiple endocrine neoplasia type 1.

Germ-line mutation analysis in patients with multiple endocrine neoplasia type 1 and related disorders

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant syndrome predisposing to tumors of the parathyroid, endocrine pancreas, anterior pituitary, adrenal glands, and diffuse neuroendocrine tissues. The MEN1 gene has been assigned, by linkage analysis and loss of heterozygosity, to chromosome 11q13 and recently has been identified by positional cloning. In this study, a total of 84 families and/or isolated patients with either MEN1 or MEN1-related inherited endocrine tumors were screened for MEN1 germ-line mutations, by heteroduplex and sequence analysis of the MEN1 gene-coding region and untranslated exon 1. Germ-line MEN1 alterations were identified in 47/54 (87%) MEN1 families, in 9/11 (82%) isolated MEN1 patients, and in only 6/19 (31.5%) atypical MEN1-related inherited cases. We characterized 52 distinct mutations in a total of 62 MEN1 germ-line alterations. Thirty-five of the 52 mutations were frameshifts and nonsense mutations predicted to encode for a truncated MEN1 protein. We identified eight missense mutations and five in-frame deletions over the entire coding sequence. Six mutations were observed more than once in familial MEN1. Haplotype analysis in families with identical mutations indicate that these occurrences reflected mainly independent mutational events. No MEN1 germ-line mutations were found in 7/54 (13%) MEN1 families, in 2/11 (18%) isolated MEN1 cases, in 13/19 (68. 5%) MEN1-related cases, and in a kindred with familial isolated hyperparathyroidism. Two hundred twenty gene carriers (167 affected and 53 unaffected) were identified. No evidence of genotype-phenotype correlation was found. Age-related penetrance was estimated to be >95% at age >30 years. Our results add to the diversity of MEN1 germ-line mutations and provide new tools in genetic screening of MEN1 and clinically related cases.

Expression of the MEN-1 gene in a large kindred with multiple endocrine neoplasia type 1

In 1983 a large family with MEN-1 (designated Tasman 1) was identified in Tasmania. Kindred screening and case follow-up over the subsequent 15 years has yielded data on over 160 MEN-1-affected patients. Hyperparathyroidism is present in over 60% of gene carriers by age 20 years and 95% by age 30 years. Hyperplasia is the characteristic pathological finding. Kaplan-Meier analysis indicates hyperparathyroidism recurs in the majority of patients despite near-total parathyroidectomy. Gastrinoma, 'nonfunctioning' pancreatic adenoma and insulinoma occur in up to 60, 50 and 10% of patients, respectively. Metastatic gastroenteropancreatic (GEP) tumours develop in up to 35% of family members, being frequent in some branches of Tasman 1, whilst rare in others. Pituitary disease developed in 19% of patients. Prolactinoma and 'nonfunctioning' adenoma account for 76 and 24%, respectively, of pituitary abnormalities. Prolactinomas exhibit clustering within branches of the Tasman 1 kindred. Adrenal adenomas occur in 36% of patients. The majority of adrenal lesions are benign and nonsecretory and develop in association with pancreatic neoplasia. Carcinoid tumours are uncommon but important malignancies. Malignant thymic carcinoid occurs in male patients, whereas bronchial carcinoid occurs predominantly in women. Prior to recognition of MEN-1 in Tasman 1, complications of hyperparathyroidism and malignancy accounted for the majority of patient mortality. Since commencement of prospective screening, malignant GEP tumours and cardiovascular disease have become the most prevalent causes of death amongst MEN-1-affected patients.