Biochemical, bone and renal patterns in hyperparathyroidism associated with multiple endocrine neoplasia type 1

Primary hyperparathyroidism associated with multiple endocrine neoplasia type I (hyperparathyroidism/multiple endocrine neoplasia type 1) differs in many aspects from sporadic hyperparathyroidism, which is the most frequently occurring form of hyperparathyroidism. Bone mineral density has frequently been studied in sporadic hyperparathyroidism but it has very rarely been examined in cases of hyperparathyroidism/multiple endocrine neoplasia type 1. Cortical bone mineral density in hyperparathyroidism/multiple endocrine neoplasia type 1 cases has only recently been examined, and early, severe and frequent bone mineral losses have been documented at this site. Early bone mineral losses are highly prevalent in the trabecular bone of patients with hyperparathyroidism/multiple endocrine neoplasia type 1. In summary, bone mineral disease in multiple endocrine neoplasia type 1 related hyperparathyroidism is an early, frequent and severe disturbance, occurring in both the cortical and trabecular bones. In addition, renal complications secondary to sporadic hyperparathyroidism are often studied, but very little work has been done on this issue in hyperparathyroidism/multiple endocrine neoplasia type 1. It has been recently verified that early, frequent, and severe renal lesions occur in patients with hyperparathyroidism/multiple endocrine neoplasia type 1, which may lead to increased morbidity and mortality. In this article we review the few available studies on bone mineral and renal disturbances in the setting of hyperparathyroidism/multiple endocrine neoplasia type 1. We performed a meta-analysis of the available data on bone mineral and renal disease in cases of multiple endocrine neoplasia type 1-related hyperparathyroidism.     

Surgical approach in patients with hyperparathyroidism in multiple endocrine neoplasia type 1: total versus partial parathyroidectomy

Usually, primary hyperparathyroidism is the first endocrinopathy to be diagnosed in patients with multiple endocrine neoplasia type 1, and is also the most common one. The timing of the surgery and strategy in multiple endocrine neoplasia type 1/hyperparathyroidism are still under debate. The aims of surgery are to: 1) correct hypercalcemia, thus preventing persistent or recurrent hyperparathyroidism; 2) avoid persistent hypoparathyroidism; and 3) facilitate the surgical treatment of possible recurrences. Currently, two types of surgical approach are indicated: 1) subtotal parathyroidectomy with removal of at least 3-3 K glands; and 2) total parathyroidectomy with grafting of autologous parathyroid tissue. Transcervical thymectomy must be performed with both of these procedures. Unsuccessful surgical treatment of hyperparathyroidism is more frequently observed in multiple endocrine neoplasia type 1 than in sporadic hyperparathyroidism. The recurrence rate is strongly influenced by: 1) the lack of a pre-operative multiple endocrine neoplasia type 1 diagnosis; 2) the surgeon's experience; 3) the timing of surgery; 4) the possibility of performing intra-operative confirmation (histologic examination, rapid parathyroid hormone assay) of the curative potential of the surgical procedure; and, 5) the surgical strategy. Persistent hyperparathyroidism seems to be more frequent after subtotal parathyroidectomy than after total parathyroidectomy with autologous graft of parathyroid tissue. Conversely, recurrent hyperparathyroidism has a similar frequency in the two surgical strategies. To plan further operations, it is very helpful to know all the available data about previous surgery and to undertake accurate identification of the site of recurrence.     

Total parathyroidectomy in a large cohort of cases with hyperparathyroidism associated with multiple endocrine neoplasia type 1: experience from a single academic center

Most cases of sporadic primary hyperparathyroidism present disturbances in a single parathyroid gland and the surgery of choice is adenomectomy. Conversely, hyperparathyroidism associated with multiple endocrine neoplasia type 1 (hyperparathyroidism/multiple endocrine neoplasia type 1) is an asynchronic, asymmetrical multiglandular disease and it is surgically approached by either subtotal parathyroidectomy or total parathyroidectomy followed by parathyroid auto-implant to the forearm. In skilful hands, the efficacy of both approaches is similar and both should be complemented by prophylactic thymectomy. In a single academic center, 83 cases of hyperparathyroidism/ multiple endocrine neoplasia type 1 were operated on from 1987 to 2010 and our first surgical choice was total parathyroidectomy followed by parathyroid auto-implant to the non-dominant forearm and, since 1997, associated transcervical thymectomy to prevent thymic carcinoid. Overall, 40% of patients were given calcium replacement (mean intake 1.6 g/day) during the first months after surgery, and this fell to 28% in patients with longer follow-up. These findings indicate that several months may be needed in order to achieve a proper secretion by the parathyroid auto-implant. Hyperparathyroidism recurrence was observed in up to 15% of cases several years after the initial surgery. Thus, long-term follow-up is recommended for such cases. We conclude that, despite a tendency to subtotal parathyroidectomy worldwide, total parathyroidectomy followed by parathyroid auto-implant is a valid surgical option to treat hyperparathyroidism/multiple endocrine neoplasia type 1. Larger comparative systematic studies are needed to define the best surgical approach to hyperparathyroidism/multiple endocrine neoplasia type 1.     

Premature centromere division in patients with multiple endocrine neoplasia type 1

Frequency of mitoses with premature centromere division (PCD) was examined in lymphocytes from subjects with multiple endocrine neoplasia type 1 (MEN 1). An increase in PCD after exposure to an alkylating agent was observed in subjects with MEN 1 who carry a heterozygous MEN1 gene mutation but not in normal controls or in affected subjects without the MEN1 gene mutation. These findings support the inclusion of MEN 1 as a chromosome instability syndrome and recognition of PCD as a manifestation of chromosome instability. Furthermore, these results suggest that the MEN1 gene product may function to maintain the integrity of DNA.     

Surgical treatment of pancreatic endocrine tumors in multiple endocrine neoplasia type 1

Surgical approaches to pancreatic endocrine tumors associated with multiple endocrine neoplasia type 1 may differ greatly from those applied to sporadic pancreatic endocrine tumors. Presurgical diagnosis of multiple endocrine neoplasia type 1 is therefore crucial to plan a proper intervention. Of note, hyperparathyroidism/multiple endocrine neoplasia type 1 should be surgically treated before pancreatic endocrine tumors/multiple endocrine neoplasia type 1 resection, apart from insulinoma. Non-functioning pancreatic endocrine tumors/multiple endocrine neoplasia type 1 >1 cm have a high risk of malignancy and should be treated by a pancreatic resection associated with lymphadenectomy. The vast majority of patients with gastrinoma/multiple endocrine neoplasia type 1 present with tumor lesions at the duodenum, so the surgery of choice is subtotal or total pancreatoduodenectomy followed by regional lymphadenectomy. The usual surgical treatment for insulinoma/multiple endocrine neoplasia type 1 is distal pancreatectomy up to the mesenteric vein with or without spleen preservation, associated with enucleation of tumor lesions in the pancreatic head. Surgical procedures for glucagonomas, somatostatinomas, and vipomas/ multiple endocrine neoplasia type 1 are similar to those applied to sporadic pancreatic endocrine tumors. Some of these surgical strategies for pancreatic endocrine tumors/multiple endocrine neoplasia type 1 still remain controversial as to their proper extension and timing. Furthermore, surgical resection of single hepatic metastasis secondary to pancreatic endocrine tumors/multiple endocrine neoplasia type 1 may be curative and even in multiple liver metastases surgical resection is possible. Hepatic trans-arterial chemo-embolization is usually associated with surgical resection. Liver transplantation may be needed for select cases. Finally, pre-surgical clinical and genetic diagnosis of multiple endocrine neoplasia type 1 syndrome and localization of multiple endocrine neoplasia type 1 related tumors are crucial for determining the best surgical strategies in each individual case with pancreatic endocrine tumors.     

Surgical approach to medullary thyroid carcinoma associated with multiple endocrine neoplasia type 2

We briefly review the surgical approaches to medullary thyroid carcinoma associated with multiple endocrine neoplasia type 2 (medullary thyroid carcinoma/multiple endocrine neoplasia type 2). The recommended surgical approaches are usually based on the age of the affected carrier/patient, tumor staging and the specific rearranged during transfection codon mutation. We have focused mainly on young children with no apparent disease who are carrying a germline rearranged during transfection mutation. Successful management of medullary thyroid carcinoma in these cases depends on early diagnosis and treatment. Total thyroidectomy should be performed before 6 months of age in infants carrying the rearranged during transfection 918 codon mutation, by the age of 3 years in rearranged during transfection 634 mutation carriers, at 5 years of age in carriers with level 3 risk rearranged during transfection mutations, and by the age of 10 years in level 4 risk rearranged during transfection mutations. Patients with thyroid tumor >5 mm detected by ultrasound, and basal calcitonin levels >40 pg/ml, frequently have cervical and upper mediastinal lymph node metastasis. In the latter patients, total thyroidectomy should be complemented by extensive lymph node dissection. Also, we briefly review our data from a large familial medullary thyroid carcinoma genealogy harboring a germline rearranged during transfection Cys620Arg mutation. All 14 screened carriers of the rearranged during transfection Cys620Arg mutation who underwent total thyroidectomy before the age of 12 years presented persistently undetectable serum levels of calcitonin (<2 pg/ml) during the follow-up period of 2-6 years. Although it is recommended that preventive total thyroidectomy in rearranged during transfection codon 620 mutation carriers is performed before the age of 5 years, in this particular family the surgical intervention performed before the age of 12 years led to an apparent biochemical cure.     

A case of multiple endocrine neoplasia type 1 combined with papillary thyroid carcinoma

This is the first report of papillary thyroid carcinoma combined with multiple endocrine neoplasia type 1 (MEN1) in Korea. MEN1 is a hereditary disease comprising neoplastic disorders such as pituitary, parathyroid and pancreatic neuroendocrine tumor, such as gastrinoma. But papillary thyroid cancer was never regarded as its component before in Korea. Herein we present a 39-year-old woman who manifested typical features of MEN1 with a coincidental papillary thyroid carcinoma. Although the family history of MEN1 was definite, her genetic analysis of DNA had revealed no germline mutation in MEN1 gene locus. Unidentified culprit gene unable us further genetic study to find LOH (loss of heterogeneity) in 11q13, the possible explanation of papillary thyroid carcinoma as a new component of MEN1. As we have first experienced a case of MEN1 combined with papillary thyroid carcinoma in Korea, we report it with the review of literature.     

Clonality of parathyroid tumors in familial multiple endocrine neoplasia type 1

Familial multiple endocrine neoplasia type 1 (MEN-1) is characterized by tumors of the parathyroids, endocrine pancreas, and anterior pituitary. Since the gene associated with MEN-1, located on chromosome 11 (11q13), may normally inhibit tumor proliferation, tumors could arise from inactivation of one or both of the alleles. However, parathyroid tumors in patients with MEN-1 have been considered to result from polyclonal hyperplasia. Using genetic probes, we tested parathyroid tumors for a monoclonal component, represented by a loss of alleles at any of eight loci along chromosome 11. Ten of 16 tumors from 14 patients with familial MEN-1 had losses of alleles from chromosome 11. Tumors with losses were larger than those without (1.6 vs. 0.2 g; P less than 0.002), suggesting that a monoclonal adenoma may develop after a phase of polyclonal hyperplasia. In 7 of 10 tumors, the subregion of loss was less than the full length of chromosome 11 but always included one copy of the MEN-1 locus. Of 34 sporadic adenomas from patients without MEN-1, 9 showed similar allelic losses in chromosome 11; in 7 the losses included the apparent MEN-1 locus. We conclude that many "hyperplastic" parathyroid tumors in familial MEN-1 are in fact monoclonal and may progress or even begin to develop by inactivation of the MEN-1 gene (at 11q13) in a precursor cell. Some sporadic adenomas have allelic losses on chromosome 11, which may also involve the MEN-1 gene.     

Novel MEN1 gene mutations in familial multiple endocrine neoplasia type 1

The recent isolation of the gene responsible for multiple endocrine neoplasia type 1 (MEN 1) has enabled direct genetic diagnosis for people with endocrine tumors and family members of affected patients. Although MEN 1 is rarely recognized in the Japanese population compared to its prevalence in Caucasians, we have previously reported a high prevalence of this disease in a limited area (Nagano Prefecture; population, 2.15 million). In this communication, we report mutations of the MEN1 gene in kindreds living in Nagano Prefecture. The absence of a common mutation among these kindreds indicates that the high prevalence of MEN 1 in this area is not due to a regional accumulation of patients descended from a common ancestor. This result implies that the prevalence of MEN 1 in other areas of Japan could also be higher than had been thought. Received: March 18, 1998 / Accepted: April 24, 1998     

Molecular diagnosis of multiple type 2 endocrine neoplasia

The paper reviews the data on the molecular structure of the protooncogene RET encoding for receptor-type protein kinase, on the mechanism of transformation of the normal protooncogene RET to a dominant transforming oncogene, and on RET mutations detected in patients with the MEN-2 syndrome. Moreover, it presents the authors' own findings. The familial medullary thyroid carcinoma burdened genealogy shows a new point mutation TCG(Ser)-->GCG(Ala) in codon 891, in the exon 15 of the protooncogene RET. This mutation was not detected in the chromosomes of healthy individuals. Analyzing the linkage with two known and two new polymorphic markers showed that there was a cisaggregation of informative polymorphic markers, phenotypic manifestation of the disease, and mutations in the genealogy in question. In the protooncogene RET, there were two new polymorphisms: G/A at position 24 in intron 14 and C/T in codon 836 (exon 14). The rate of the polymorphism encountered in codon 836 proved to be similar for the Russians and the Germans (0.96%), which was also seen for two earlier described polymorphisms in codon 691 (0.80 and 0.81, respectively) and in codon 904 (0.21 and 0.22). At the same time, there were statistically significant differences in the rates of intron 14 polymorphism (0.87 and 0.77, respectively). In a family having MEN 2, a proband displayed TGC-->CGC mutation in codon 634 of the gene RET in the heterozygous state. The mutation results in substitution of cysteine amino acid residue in the cysteine-rich extracellular domain of protein kinase encoded by the gene RET for arginine. The results of molecular analysis were used to confirm its clinical diagnosis and to indicate that effective care should be delivered in MEN 2a.     

Multiple endocrine neoplasia type 1‐associated cystic pancreatic endocrine neoplasia and multifocal cholesterol granulomas

A novel combination of tumors was found in a 68 year‐old female with Multiple Endocrine Neoplasia type‐1 (MEN 1) that included a cystic pancreatic endocrine neoplasm (CPEN), a pituitary adenoma, and multifocal cholesterol granulomas (MCGs) in the breast, pleura, and the extremities. The pancreatic tumor displayed a single central locule surrounded by a thin rim of neoplastic parenchyma. The tumor showed heterogeneity in the architecture that included glandular, trabecular and solid patterns. The tumor cells of the pancreas were immunohistochemically positive for both endocrine and pancreatic acinar markers including chromogranin A, synaptophysin, glucagon, lipase, and reg protein. Electron microscopy revealed that there were numerous smaller dense‐cored neurosecretory granules, larger zymogen‐like granules and microvilli on the apical side of the tumor cells. The pancreatic tumor was diagnosed as CPEN with acinar cell features. Analysis of the DNA extracted from the tissues revealed that there is a MEN1 germline mutation in exon 10 codon 527, and somatic mutation in exon 2 codon 32 in the pancreatic tumor, and one base pair deletion in exon 2 codon 79 in the pituitary adenoma. Here, we report the case and discuss possible pathogenesis of CPEN and MCGs in a patient with MEN 1.     

Early diagnosis of multiple endocrine neoplasia type IIa

Summary We report on incidental findings during family screening of two kindreds with multiple endocrine neoplasia type IIa. Pheochromocytoma and medullary thyroid carcinoma of considerable size were detected. The results underline the importance of early diagnosis of the syndrome, since the afflicted may be almost or wholly asymptomatic. High resolution chromosome banding studies were carried out in both families, but no abnormality was found. Linkage analysis using DNA markers closely related to the chromosomal locus at chromosome 10 was carried out and was positive in two asymptomatic offspring of one family, whereas the markers were not informative in a second family. We recommend early linkage analysis for establishing the genetic status in offspring of multiple endocrine neoplasia type IIa families to identify for further screening those who are predicted to be gene carrier.Abbreviations MEN Multiple endocrine neoplasia - Q-Banding=QFQ-Banding Q-bands labeled by quinacrine florescence using quinacrine staining - R-Banding=RBA-Banding R-bands labeled by BrdU incorporation and acridine-orange staining - BrdU Bromodeoxyuridine - RFLP Restriction fragment length polymorphism - MIBG Metaiodobenzylguanidine     

Genotype-phenotype correlation in multiple endocrine neoplasia type 2

Multiple endocrine neoplasia type 2 is an autosomal-dominant hereditary cancer syndrome caused by missense gain-of-function mutations of the rearranged during transfection proto-oncogene, which encodes the receptor tyrosine kinase, on chromosome 10. It has a strong penetrance of medullary thyroid carcinomas and can be associated with bilateral pheochromocytoma and primary hyperparathyroidism. Multiple endocrine neoplasia type 2 is divided into three varieties depending on its clinical features: multiple endocrine neoplasia type 2A, multiple endocrine neoplasia type 2B, and familial medullary thyroid carcinoma. The specific rearranged during transfection mutation may suggest a predilection toward a particular phenotype and clinical course of medullary thyroid carcinoma, with strong genotype-phenotype correlations. Offering rearranged during transfection testing is the best practice for the clinical management of patients at risk of developing multiple endocrine neoplasia type 2, and multiple endocrine neoplasia type 2 has become a classic model for the integration of molecular medicine into patient care. Recommendations on the timing of prophylactic thyroidectomy and extent of surgery are based on the classification of rearranged during transfection mutations into risk levels according to genotype-phenotype correlations. Earlier identification of patients with hereditary medullary thyroid carcinoma can change the presentation from clinical tumor to preclinical disease, resulting in a high cure rate of affected patients and a much better prognoses.     

Surgical management of pancreatico-duodenal tumors in multiple endocrine neoplasia syndrome type 1

Pancreatico-duodenal tumors are the second most common endocrinopathy in multiple endocrine neoplasia syndrome type 1, and have a pronounced effect on life expectancy as the principal cause of disease-related death. Previous discussions about surgical management have focused mainly on syndromes of hormone excess and, in particular, the management of multiple endocrine neoplasia syndrome type 1-related Zollinger-Ellison syndrome. Since hormonal syndromes tend to occur late and indicate the presence of metastases, screening with biochemical markers and endoscopic ultrasound is recommended for early detection of pancreatico-duodenal tumors, and with early surgery before metastases have developed. Surgery is recommended in patients with or without hormonal syndromes in the absence of disseminated liver metastases. The suggested operation includes distal 80% subtotal pancreatic resection together with enucleation of tumors in the head of the pancreas, and in cases with Zollinger-Ellison syndrome, excision of duodenal gastrinomas together with clearance of regional lymph node metastases. This strategy, with early and aggressive surgery before metastases have developed, is believed to reduce the risks for tumor recurrence and malignant progression.     

Parathyroid mitogenic activity in plasma from patients with familial multiple endocrine neoplasia type 1

Hyperplasia of the parathyroid glands is a central feature of familial multiple endocrine neoplasia type 1. We used cultured bovine parathyroid cells to test for mitogenic activity in plasma from patients with this disorder. Normal plasma stimulated [3H]thymidine incorporation, on the average, to the same extent as it was stimulated in a plasma-free control culture. This contrasted with the results of the tests with plasma from patients with familial multiple endocrine neoplasia type 1, in which parathyroid mitogenic activity increased 2400 percent over the control value (P less than 0.001). Plasma from these patients also stimulated the proliferation of bovine parathyroid cells in culture, whereas plasma from normal subjects inhibited it. Parathyroid mitogenic activity in plasma from the patients with familial multiple endocrine neoplasia type 1 was greater than that in plasma from patients with various other disorders, including sporadic primary hyperparathyroidism (with adenoma, hyperplasia, or cancer of the parathyroid), sporadic primary hypergastrinemia, sporadic pituitary tumor, familial hypocalciuric hypercalcemia, and multiple endocrine neoplasia type 2 (P less than 0.05). Parathyroid mitogenic activity in the plasma of patients with familial multiple endocrine neoplasia type 1 persisted for up to four years after total parathyroidectomy. The plasma also had far more mitogenic activity in cultures of parathyroid cells than did optimal concentrations of known growth factors or of any parathyroid secretagogue. This mitogenic activity had an apparent molecular weight of 50,000 to 55,000. We conclude that primary hyperparathyroidism in familial multiple endocrine neoplasia type 1 may have a humoral cause.     

A linkage study of multiple endocrine neoplasia type IIa

Members of four families segregating for multiple endocrine neoplasia type IIa (Sipple's syndrome) were typed for 16 segregating blood group, erythrocyte enzyme, and plasma protein loci. Linkage analysis failed to find evidence favoring linkage between the multiple endocrine neoplasia mutation and any segregating marker. The data from this study were combined with the published data to rule out linkage for the HLA, ABO, Rh, or MNS loci at theta less than or equal to 0.25, the ADA, PGMI, AcP, GLOI, or GM loci at theta less than or equal to 0.10, and for GPT, PGD, or HpA at theta less than or equal to 0.05. The pooled data are inconclusive with respect to the previously suggested linkage to the P blood group locus.