Thymic carcinoids in multiple endocrine neoplasia type 1

Expressions of Cushing's syndrome in multiple endocrine neoplasia type 1

Cushing's syndrome (CS) resulting from endogenous hypercortisolism can be sporadic or can occur in the context of familial disease because of pituitary or extra-pituitary neuroendocrine tumors. Multiple endocrine neoplasia type 1 (MEN1) is unique among familial endocrine tumor syndromes because hypercortisolism in this context can result from pituitary, adrenal, or thymic neuroendocrine tumors and can therefore reflect either ACTH-dependent or ACTH-independent pathophysiologies. The prominent expressions of MEN1 include primary hyperparathyroidism, tumors of the anterior pituitary, gastroenteropancreatic neuroendocrine tumors, and bronchial carcinoid tumors along with several common non-endocrine manifestations such as cutaneous angiofibromas and leiomyomas. Pituitary tumors are present in about 40% of MEN1 patients, and up to 10% of such tumors secrete ACTH that can result in Cushing's disease. Adrenocortical neoplasms occur frequently in MEN1. Although such adrenal tumors are mostly clinically silent, this category can include benign or malignant tumors causing hypercortisolism and CS. Ectopic tumoral ACTH secretion has also been observed in MEN1, almost exclusively originating from thymic neuroendocrine tumors. The range of clinical presentations, etiologies, and diagnostic challenges of CS in MEN1 are reviewed herein with an emphasis on the medical literature since 1997, when the MEN1 gene was identified.

Multiple endocrine neoplasia 1: a broad overview

This review article discusses the diagnoses and treatment of patients with multiple endocrine neoplasia type 1 (MEN 1). The most common tumors associated with MEN 1 are located in the pancreas, pituitary, and parathyroid glands. Less common tumors include neuroendocrine tumors of the lung and thymus, adrenal tumors, and cutaneous lesions. This article describes the diagnosis, clinical manifestations, treatment, and surveillance of tumors associated with patients who are diagnosed with MEN 1.

Primary thymic atypical carcinoid with rare multiple bone metastasis: A case report and literature review

Primary thymic atypical carcinoid (TAC) is a type of extremely rare neuroendocrine tumor. Approximately one-third of patients with TAC tumors are asymptomatic, and no treatments of TAC have been rigorously tested in multicenter clinical trials. To date, there has been no previous case report of TACs with multiple skull metastases. The present report describes a case of a 56-year-old male patient with a primary TAC and multiple axial skeleton metastases, including multiple bilateral metastases to the parietal bones, outer wall of the orbital cavities, and the petrous apex, as well as metastases to the suprasellar region and the clivus. The histological examination confirmed the diagnosis of TAC. Single-photon emission computed tomography, computed tomography and magnetic resonance imaging scans revealed multiple bone metastases. The patient refused chemotherapy and radiotherapy and only accepted alleviative treatment, and died 89 days after diagnosis. This type of cancer is highly malignant with an extremely short natural course and high disease-related mortality. In addition, a review of the literature was performed to provide a reference for proper diagnosis and treatment of TACs.

A rare case of thymic carcinoid presenting with gastrointestinal symptoms and pericardium effusion

Background

Thymic carcinoid is one of an extremely rare type of malignant neuroendocrine tumor with a poor prognosis. Invasion of thymic carcinoid to other organs could lead to devastating consequences. It has been reported that thymic carcinoid mainly invaded to the pleura, lungs, liver, pancreas and bone, while rarely to the cardiac, especially to the ventricle.

Case presentation

A 53-year-old man presented with gastrointestinal symptoms and persistent pericardial effusion. Multiple imaging tools, including chest computed tomography (CT), magnetic resonance imaging (MRI), 18F-Fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) showed a malignant neoplasm arising from the thymus invading into the biventricular myocardium, pericardium, and left superior pulmonary veins. The tumor was finally diagnosed as a thymic carcinoid through pathological examination.

Conclusion

This is a rare case of thymic carcinoid invading the ventricular myocardium, which presented as subacute heart failure. The observations in this case would be useful for differential diagnosis of primary heart disease and invasion of heart due to thymic carcinoid.

First Case of Mature Teratoma and Yolk Sac Testis Tumor Associated to Inherited MEN-1 Syndrome

Introduction: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominantly inherited endocrine tumor syndrome characterized by the development of cancer in various endocrine organs, particularly in the pituitary, parathyroid and pancreas. Moreover, in some cases, also non-endocrine tumors can be diagnosed, developing atypical phenotypes. Case report: We report herein the clinical history of a patient affected by MEN-1 syndrome who developed atypical features for this disease. The patient's clinical history started in August 2015 when he was referred, at the age of 23 years, to the Emergency Department of our Hospital for the occurrence of progressive asthenia, weakness, tremors and syncope. The biochemical test documented hyper-calcemia and severe hypoglycemia. The patient was referred to our Neuroendocrine Tumor and Pituitary Unit and he was diagnosed with pancreatic insulinoma, hypercalcemic hyperparathyroidism, and a prolactin secreting pituitary adenoma. The MEN-1 syndrome was suspected and genetic tests for mutation of menin resulted positive for the pathogenic variant c1548dupG. In January 2016, the patient was diagnosed with intratubular germ cell neoplasia, consisting of a mature teratoma and yolk sac tumor and he underwent a right orchiectomy. Conclusion: This is the first case report showing the clear association of MEN-1 syndrome with yolk sac tumors and teratomas, as in our case, the c1548dupG represents a pathogenic variant rather than a SNP. This case suggests the opportunity of an accurate evaluation of the testis particularly in young MEN-1 affected patients and that a prompt screening for neoplastic disease should involve all the endocrine glands.

Evaluation of the prognostic value of surgery and postoperative radiotherapy for patients with thymic neuroendocrine tumors: A propensity-matched study based on the SEER database

Background

The prognostic value of surgery and postoperative radiotherapy (PORT) for primary thymic neuroendocrine tumors (TNETs) was estimated using the SEER database.

Methods

This retrospective study used SEER data of TNET patients between 1998 and 2015. Propensity score matching (PSM) was performed according to whether surgery was performed. The prognostic effects on overall survival (OS) and cancer‐specific survival (CSS) were evaluated using multivariate Cox regression.

Results

A total of 3947 patients were included: 293 (7.4%) TNET, 2788 (70.6%) thymoma, and 866 (21.9%) thymic carcinoma. Compared to other subtypes, TNET patients were younger, included a larger proportion of men, had a well or moderately differentiated histological grade, higher disease stage at diagnosis, and were more likely to have regional lymph node metastasis. The median OS and CSS for TNET were 82.9 (95% confidence interval 74.3–91.4) and 101.9 (95% confidence interval 91.9–111.8) months, respectively, significantly shorter than for thymomas. In the matched cohort of TNET patients, multivariate analysis of OS and CSS revealed a significantly poorer prognosis in the non‐surgery group (P < 0.001). Compared to total/radical resection, TNET patients who underwent debulking resection had significantly inferior outcomes (P < 0.05). Postoperative radiotherapy favorably impacted OS and CSS in Masaoka–Koga stage III–IV TNET patients; this OS impact was also observed in stage IIB patients.

Conclusion

TNETs are extremely rare with relatively dismal outcomes. This analysis revealed the role of complete surgical resection and the favorable effect of postoperative radiotherapy in specific TNET subgroups.

Primary neuroendocrine carcinoma of the thymus: A retrospective analysis from a regional cancer center in Western India

Primary neuroendocrine tumors of the thymus are unusual anterior mediastinal tumors with a variable prognosis. A retrospective analysis of five patients with primary neuroendocrine tumors of the thymus admitted to the Gujarat Cancer and Research Institute, Ahmedabad, between 2012 and 2016, was done to study the clinical profile and outcome of these patients. The role of various prognostic factors such as surgical resection, histological grade, and Masaoka-Koga staging was also analyzed. Majority of the patients present with signs and symptoms related to a rapidly expanding mediastinal mass, such as breathlessness, facial puffiness, edema over the neck and extremities, chest pain, and other features of superior vena cava (SVC) syndrome. Collateral venous dilatation over the neck and chest and edema over neck were the most common physical signs. All the patients enrolled in the study presented in advanced stages with a poor differentiation on histopathological examination. Thymic neuroendocrine tumors usually manifest as large, lobulated, and locally invasive anterior mediastinal masses surrounding the great vessels of the neck and thorax. None of the diagnosed patients underwent surgical resection in view of extensive vascular encasement in the neck and thorax, and all of them were started on platinum-based palliative chemotherapy. The median survival of the patients was 12 months with the longest survival of 16 months for one patient. Possibility of this potentially rare entity should be kept in mind when a patient presents with features of SVC syndrome and large mediastinal mass. Complete surgical resection of the tumor is prognostic of improved treatment outcome and long-term survival. Large tumor size could be a determinant of poor overall outcome, and tumor size should strongly be considered as a factor in the revised (NETT) Neuroendocrine tumours of thymus staging. Histological grade and Masaoka-Koga stage are the important prognostic factors, but this study emphasizes the utmost need to further validate the prognostic factors.

Type B1 Thymoma in Multiple Endocrine Neoplasia Type 1 (Men-1) Syndrome

Aims and Background

Multiple endocrine neoplasia (MEN) syndromes include a group of disorders characterized by the neoplastic transformation of two or more endocrine tissues. In type 1 syndrome (MEN-1), pituitary, parathyroid and pancreatic islet tumors are most frequently represented. Thymic neoplasms are also rarely associated, and thymectomy during subtotal or total parathyroidectomy should always be considered.

Study design

The authors describe a rare case of a 22-year-old male who presented a type B1 thymoma without myasthenia gravis associated to hyperparathyroidism, corticoadrenal adenoma and three neuroendocrine pancreatic lesions (somato-statinoma, glucagonoma and insulinoma).

Neuroendocrine tumors of the thymus

Primary neuroendocrine tumors of the thymus (NETTs) are rare and biologically very aggressive neoplasms, usually located in the anterior mediastinal space. They are more frequently observed in males, in their fourth/fifth decades of life. In 50% of cases, NETTs are associated with endocrinopaties [Cushing's syndrome, acromegaly or Multiple Endocrine Neoplasia-1 (MEN-1) syndrome]. NETTs very often present with invasion of the surrounding mediastinal anatomical structures. Surgery, even in advanced stages, is the mainstay of treatment: a compete resection through a median sternotomy or a combined access (sternotomy + thoracotomy) should be always attempted. Induction chemotherapy (± radiotherapy) is usually administered in advanced neoplasms, with the aim to achieve tumor shinkage, increasing, therefore, the chance to obtain a complete resection. Postoperative radiotherapy (± chemotherapy) is administered in case of invasive lesions, or incomplete resections. NETTs long-term outcome is poor, even in case of completely resected tumors, due to high risk of recurrence or distant metastases development. Prognosis mainly depends on tumor stage, invasivity, completeness of resection, possible association with endocrinopaties and recurrence/distant metastases development.

Neuroendocrine tumors of the thymus and mediastinum

Neuroendocrine tumors of the thymus (tNET) and mediastinum are very rare neoplasms with scarce available data. All subtypes [typical and atypical carcinoid tumors (TC and AC), large cell neuroendocrine and small cell carcinoma (SCC)] observed elsewhere in the body occur also in the mediastinum and show only few if any organ-specific morphological differences. Although all available data suggest that the broad principles that govern the biology (and hence) the classification of these tumors in general apply also to tNET, there are a few noteworthy peculiarities related e.g., to risk factors, relative frequency and also to molecular genetic features. In this review, we will briefly summarize current knowledge on tNET with a special emphasis on shared and private features in comparison e.g., with pulmonary NET, which have traditionally been regarded the next closely related NET group.

Classification of pulmonary neuroendocrine tumors: new insights

Neuroendocrine tumors of the lung (Lu-NETs) embrace a heterogeneous family of neoplasms classified into four histological variants, namely typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC). Defining criteria on resection specimens include mitotic count in 2 mm2 and the presence or absence of necrosis, alongside a constellation of cytological and histological traits including cell size and shape, nuclear features and overall architecture. Clinically, TC are low-grade malignant tumors, AC intermediate-grade malignant tumors and SCLC/LCNEC high-grade malignant full-blown carcinomas with no significant differences in survival between them. Homologous tumors arise in the thymus that occasionally have some difficulties in differentiating from the lung counterparts when presented with large unresectable or metastatic lesions. Immunohistochemistry (IHC) helps refine NE diagnosis at various anatomical sites, particularly on small-sized tissue material, in which only TC and small cell carcinoma categories can be recognized easily on hematoxylin & eosin stain, while AC and LCNEC can only be suggested on such material. The Ki-67 labeling index effectively separates carcinoids from small cell carcinoma and may prove useful for the clinical management of a metastatic disease to help the therapeutic decision-making process. Although carcinoids and high-grade neuroendocrine carcinomas in the lung and elsewhere make up separate tumor categories on molecular grounds, emerging data supports the concept of secondary high-grade NETs arising in the preexisting carcinoids, whose clinical and biological relevance will have to be placed into the proper context for the optimal management of these patients. In this review, we will discuss the selected, recent literature with a focus on current issues regarding Lu-NET nosology, i.e., classification, derivation and tumor evolution.

Thymus neuroendocrine tumors with CTNNB1 gene mutations, disarrayed ß-catenin expression, and dual intra-tumor Ki-67 labeling index compartmentalization challenge the concept of secondary high-grade neuroendocrine tumor: a paradigm shift

We herein report an uncommon association of intimately admixed atypical carcinoid (AC) and large cell neuroendocrine (NE) carcinoma (LCNEC) of the thymus, occurring in two 20- and 39-year-old Caucasian males. Both tumors were treated by maximal thymectomy. The younger patient presented with a synchronous lesion and died of disease after 9 months, while the other patient was associated with a recurrent ectopic adrenocorticotropic hormone Cushing's syndrome and is alive with disease at the 2-year follow-up. MEN1 syndrome was excluded in either case. Immunohistochemically, disarrayed cytoplasmic and nuclear ß-catenin expression was seen alongside an intra-tumor Ki-67 antigen labeling index (LI) ranging from 2 to 80% in the younger patient's tumor and from 3 to 45% in the other. Both exhibited upregulated cyclin D1 and retinoblastoma, while vimentin was overexpressed in the recurrent LCNEC only. Next-generation sequencing revealed CTNNB1, TP53, and JAK3 mutations in the synchronous tumor and CTNNB1 mutation alone in the metachronous tumor (the latter with the same mutation as the first tumor of 17 years prior). None of the 23 T-NET controls exhibited this hallmarking triple alteration (p = 0.003). These findings suggested that LCNEC components developed from pre-existing CTNNB1-mutated AC upon loss-of-function TP53 and gain-of-function JAK3 mutations in one case and an epithelial-mesenchymal transition upon vimentin overexpression in the other case. Both tumors maintained intact cyclin D1-retinoblastoma machinery. Our report challenges the concept of secondary LCNEC as an entity that develops from pre-existing AC as a result of tumor progression, suggesting a paradigm shift to the current pathogenesis of NET.

Whole exome sequencing of thymic neuroendocrine tumor with ectopic ACTH syndrome

OBJECTIVE

Thymic neuroendocrine tumor is the second-most prevalent cause of ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS), which is a rare disease characterized by ectopic ACTH oversecretion from nonpituitary tumors. However, the genetic abnormalities of thymic neuroendocrine tumors with EAS remain largely unknown. We aim to elucidate the genetic abnormalities and identify the somatic mutations of potential tumor-related genes of thymic neuroendocrine tumors with EAS by whole exome sequencing.

DESIGN AND METHODS

Nine patients with thymic neuroendocrine tumors with EAS who were diagnosed at Shanghai Clinical Center for Endocrine and Metabolic Diseases in Ruijin Hospital between 2002 and 2014 were enrolled. We performed whole exome sequencing on the DNA obtained from thymic neuroendocrine tumors and matched peripheral blood using the Hiseq2000 platform.

RESULTS

We identified a total of 137 somatic mutations (median of 15.2 per tumor; range, 1-24) with 129 single-nucleotide mutations (SNVs). The predominant substitution in these mutations was C:G > T:A transition. Approximately 80% of detected mutations resulted in amino acid changes. However, we failed to discover any recurrent mutations in these nine patients. By functional predictions, HRAS, PAK1 and MEN1, previously reported in neuroendocrine tumors, were identified as candidate tumor-related genes associated with thymic neuroendocrine tumors.

CONCLUSIONS

Using whole exome sequencing, we identified genetic abnormalities in thymic neuroendocrine tumors with EAS. Thereby, this study acts as a further supplement of the genetic features of neuroendocrine tumors. Somatic mutations of three potential tumor-related genes (HRAS, PAK1 and MEN1) might contribute to the tumorigenesis of thymic neuroendocrine tumors with EAS.

CT and MRI findings of thymic carcinoid

OBJECTIVE

To evaluate the CT and MRI findings of thymic carcinoid and to compare these findings with previously published findings of thymoma.

METHODS

11 cases of pathologically proven thymic carcinoid were reviewed retrospectively. Three patients had typical carcinoid, and eight patients had atypical carcinoid. The characteristics of the tumours and related thoracic abnormalities were assessed in each case on CT and/or MRI by two chest radiologists. The final decisions on the findings were reached by consensus.

RESULTS

Thymic carcinoids were more likely to have a large mass (ranging from 18 to 105 mm), irregular contours (n = 8), heterogeneous intensity on T₂ weighted images (n = 6; eight patients underwent MRI), heterogeneous enhancement (n = 9) and local invasion (n = 7). A necrotic or cystic component was identified in seven patients (one typical carcinoid and six atypical carcinoids). Lymphadenopathy was seen in four patients. Septum, capsule, haemorrhage and calcification were seen in three patients, two patients, two patients and one patient, respectively, with atypical carcinoid.

CONCLUSION

Thymic carcinoids tend to have a high prevalence of large masses, irregular contours, heterogeneous intensity on T₂ weighted images, heterogeneous enhancement and local invasion on CT and/or MRI. A necrotic or cystic component is often seen in atypical carcinoid. Advances in knowledge: Radiologic features of thymic carcinoid mimic those of high-risk thymomas and/or thymic carcinomas.

Clinical Features, Treatments, and Outcomes of Patients with Thymic Carcinoids and Multiple Endocrine Neoplasia Type 1 Syndrome at MD Anderson Cancer Center

Thymic carcinoids are rare neuroendocrine tumors that occur in 1-5 % of patients with multiple endocrine neoplasia type 1 (MEN1) and are a major cause of morbidity and mortality. The few published reports associate these tumors with male sex and smoking. Our objective was to describe cases of these tumors treated at our institution. We performed a retrospective chart review of all patients diagnosed with MEN1 at our tertiary referral center from 1980 to 2014. Patients with a histopathologic, fine-needle aspiration, or clinical diagnosis of a thymic carcinoid were included. Two hundred ninety-one patients fulfilled the criteria for a diagnosis of MEN1. Clinicopathologic characteristics, MEN1 genetic testing results, treatments, and survival rates were analyzed. Nine patients had a thymic carcinoid, six men (67 %) and three women (33 %). Six patients were non-smokers (67 %). Two patients had synchronous (22 %) and eight patients (89 %) had metachronous distant metastasis. The 10-year overall survival rate was 45 % (lower 95 % upper 95 % CI 20-100 %). The 10-year disease-free survival rate was 42 % (lower 95 % upper 95 % CI 15-100 %). Five patients had MEN1 genetic testing, and the genotypes of affected individuals were p.W341X, c.275_286delGCTTCACCGCCC, p.R98X, c.1350+(1_11)del11, and partial duplication of exons 9 and 10. A higher percentage of MEN1-related thymic carcinoids can occur in women and in non-smokers than previously reported. Both novel and known mutations were present in our cohort. Eighty nine percent of patients developed a metachronous metastasis from the thymic carcinoid. Patients with MEN1 and thymic carcinoids should be followed closely.

Cardiothoracic manifestations of neuroendocrine tumours

Cardiothoracic neuroendocrine tumour (NET) manifestations encompass a vast disease spectrum. Pulmonary neuroendocrine tumours represent a range of tumour grade and differentiation characteristics from pre-malignant diffuse neuroendocrine cell hyperplasia, well-differentiated, low-grade carcinoid tumours with excellent outcomes, through to high-grade small-cell lung carcinoma and large-cell neuroendocrine carcinoma with poor prognoses. Rarer thymic NETs represent a similarly wide neoplastic spectrum. Cardiac carcinoid is a paraneoplastic manifestation of the carcinoid syndrome and often the cause of mortality in NETs with hepatic metastases. Cardiothoracic NET manifestations are reviewed herein from a radiologists' perspective, discussing the diverse clinical presentations, spectrum of neoplastic and paraneoplastic manifestations, imaging features and treatment options.

Higher risk of aggressive pancreatic neuroendocrine tumors in MEN1 patients with MEN1 mutations affecting the CHES1 interacting MENIN domain

CONTEXT

Sixty to 80% of multiple endocrine neoplasia type 1 (MEN1) patients develop pancreatic neuroendocrine neoplasias (pNENs), which reveal an aggressive behavior in 10%-20% of patients. Causative MEN1 mutations in the interacting domains of the encoded Menin protein directly alter its regulation abilities and may influence the phenotype.

OBJECTIVE

The objective of the study was the evaluation of an association between MEN1 mutations in different interacting domains of Menin and the phenotype of pNENs.

DESIGN

This was a retrospective analysis of a prospectively collected cohort of 71 genetically confirmed MEN1 patients at a tertiary referral center.

MAIN OUTCOME MEASURES

Analysis of patients' characteristics and clinical phenotype of pNENs regarding the mutation type and its location in Menin interacting domains was measured.

RESULTS

Sixty-seven patients (93%) developed pNENs after a median follow-up of 134 months. Patients with mutations leading to loss of interaction (LOI) with the checkpoint kinase 1 (CHES1) interacting domain codons (428-610) compared with patients with mutations resulting in LOI with other domains (eg, JunD, Smad3) had significantly higher rates of functioning pNENs (70% vs 34%), malignant pNENs (59% vs 16%), and aggressive pNENs (37% vs 9%), respectively. Patients with CHES1-LOI also had an increased pNEN-related mortality (20% vs 4.5%). Neither gender, age, nor the ABO blood types were associated with the phenotype of pNENs.

CONCLUSIONS

MEN1 patients with MEN1 mutations leading to CHES1-LOI have a higher risk of malignant pNENs with an aggressive course of disease and disease-related death.

Primary neuroendocrine carcinoma of the thymus

Primary neuroendocrine tumors of the thymus, previously known as carcinoid tumors of the thymus, are unusual and rare tumors, and prognosis for these patients has been difficult to predict. We hereby report a case of primary neuroendocrine tumor of the thymus that had an aggressive and fatal course in spite of surgical resection and adjuvant chemotherapy. These tumors must be regarded as a malignant neoplasm that is prone to metastasize to distant sites, even after total excision.

Causes of death and prognostic factors in multiple endocrine neoplasia type 1: a prospective study: comparison of 106 MEN1/Zollinger-Ellison syndrome patients with 1613 literature MEN1 patients with or without pancreatic endocrine tumors

Multiple endocrine neoplasia type 1 (MEN1) is classically characterized by the development of functional or nonfunctional hyperplasia or tumors in endocrine tissues (parathyroid, pancreas, pituitary, adrenal). Because effective treatments have been developed for the hormone excess state, which was a major cause of death in these patients in the past, coupled with the recognition that nonendocrine tumors increasingly develop late in the disease course, the natural history of the disease has changed. An understanding of the current causes of death is important to tailor treatment for these patients and to help identify prognostic factors; however, it is generally lacking.To add to our understanding, we conducted a detailed analysis of the causes of death and prognostic factors from a prospective long-term National Institutes of Health (NIH) study of 106 MEN1 patients with pancreatic endocrine tumors with Zollinger-Ellison syndrome (MEN1/ZES patients) and compared our results to those from the pooled literature data of 227 patients with MEN1 with pancreatic endocrine tumors (MEN1/PET patients) reported in case reports or small series, and to 1386 patients reported in large MEN1 literature series. In the NIH series over a mean follow-up of 24.5 years, 24 (23%) patients died (14 MEN1-related and 10 non-MEN1-related deaths). Comparing the causes of death with the results from the 227 patients in the pooled literature series, we found that no patients died of acute complications due to acid hypersecretion, and 8%-14% died of other hormone excess causes, which is similar to the results in 10 large MEN1 literature series published since 1995. In the 2 series (the NIH and pooled literature series), two-thirds of patients died from an MEN1-related cause and one-third from a non-MEN1-related cause, which agrees with the mean values reported in 10 large MEN1 series in the literature, although in the literature the causes of death varied widely. In the NIH and pooled literature series, the main causes of MEN1-related deaths were due to the malignant nature of the PETs, followed by the malignant nature of thymic carcinoid tumors. These results differ from the results of a number of the literature series, especially those reported before the 1990s. The causes of non-MEN1-related death for the 2 series, in decreasing frequency, were cardiovascular disease, other nonendocrine tumors > lung diseases, cerebrovascular diseases. The most frequent non-MEN1-related tumor deaths were colorectal, renal > lung > breast, oropharyngeal. Although both overall and disease-related survival are better than in the past (30-yr survival of NIH series: 82% overall, 88% disease-related), the mean age at death was 55 years, which is younger than expected for the general population.Detailed analysis of causes of death correlated with clinical, laboratory, and tumor characteristics of patients in the 2 series allowed identification of a number of prognostic factors. Poor prognostic factors included higher fasting gastrin levels, presence of other functional hormonal syndromes, need for >3 parathyroidectomies, presence of liver metastases or distant metastases, aggressive PET growth, large PETs, or the development of new lesions.The results of this study have helped define the causes of death of MEN1 patients at present, and have enabled us to identify a number of prognostic factors that should be helpful in tailoring treatment for these patients for both short- and long-term management, as well as in directing research efforts to better define the natural history of the disease and the most important factors determining long-term survival at present.

Thymic neoplasm: a rare disease with a complex clinical presentation

Thymic neoplasms constitute a broad category of rare lesions with a wide spectrum of pathologic characteristics and clinical presentations which therefore require a high index of suspicion to diagnose. The natural history of the disease is seldom predictable, anywhere from an indolent to an aggressively malignant course. Although the classification and staging of these lesions are complex and controversial, complete radical surgical resection remains the gold standard of therapy. Radiation and chemotherapy are important elements of the multimodality approach to treating these patients and it is important for thoracic surgeons to work closely with their colleagues in other disciplines in the management of and future research endeavors in thymic neoplasm. In this review, we discuss the evaluation of the patient with an anterior mediastinal mass, the classification and staging of thymic neoplasms, the role of surgery, radiation and chemotherapy in treating this disease, as well as future directions in research for novel targeted therapies.

Thymic neoplasms: a clinical update

Thymoma is a unique neoplasm of the anterior mediastinum that is frequently associated with indolent growth and a variety of paraneoplastic syndromes. One third of cases are detected during the evaluation of myasthenia gravis. Classification systems of thymoma have limited ability in accurately predicting prognosis and course of disease. Thus, staging is the only way to predict clinical behavior. Encapsulated tumors that are surgically resected carry the best prognosis. Adjuvant radiotherapy is recommended for incompletely excised and most invasive thymomas. Chemotherapy in anthracycline-based chemotherapy remains the most effective chemotherapy for neoadjuvant, adjuvant or palliative treatment.

Accelerated proliferation and differential global gene expression in pancreatic islets of five-week-old heterozygous Men1 mice: Men1 is a haploinsufficient suppressor

Individuals carrying heterozygous (hz) MEN1 (Multiple Endocrine Neoplasia Syndrome Type 1) germ line mutations develop endocrine tumors as a result of somatic loss of the wild-type (wt) allele. However, endocrine cell proliferation has been observed despite wt allele retention, indicating haploinsufficiency. To study downstream molecular effects of the hz haplotype, a germ line Men1 hz mouse model was used to explore differences in global endocrine pancreatic gene expression. Because islet cells of 5-wk-old hz mice express Menin from the retained wt Men1 allele, these were isolated after collagenase digestion of the pancreas, and used for global gene expression array. Wild-type littermates were used for comparison. Array findings were corroborated by quantitative PCR, Western blotting, in situ proximity ligation assay, and immunohistochemistry. The hz islets show increased proliferation: the Ki-67 index was twice as high as in wt islets (3.48 vs. 1.74%; P = 0.024). The microarray results demonstrated that several genes were differentially expressed. Some selected genes were studied on the protein level, e.g. the cytoskeletal regulator myristoylated alanine-rich protein kinase C substrate (Marcks) was significantly less expressed in hz islets, using in situ proximity ligation assay and Western blotting (P < 0.001 and P < 0.01, respectively). Further, gene ontology analysis showed that genes with higher mRNA expression in the hz endocrine pancreas were associated with e.g. chromatin maintenance and apoptosis. Lower mRNA was observed for genes involved in growth factor binding. In conclusion, despite retained Menin expression, proliferation was accelerated, and numerous genes were differentially expressed in the endocrine pancreas of 5-wk-old hz Men1 mice, corroborating the hypothesis that MEN1 is a haploinsufficient suppressor.

Pituitary tumors in patients with MEN1 syndrome

We briefly review the characteristics of pituitary tumors associated with multiple endocrine neoplasia type 1. Multiple endocrine neoplasia type 1 is an autosomal-dominant disorder most commonly characterized by tumors of the pituitary, parathyroid, endocrine-gastrointestinal tract, and pancreas. A MEDLINE search for all available publications regarding multiple endocrine neoplasia type 1 and pituitary adenomas was undertaken. The prevalence of pituitary tumors in multiple endocrine neoplasia type 1 may vary from 10% to 60% depending on the studied series, and such tumors may occur as the first clinical manifestation of multiple endocrine neoplasia type 1 in 25% of sporadic and 10% of familial cases. Patients were younger and the time between initial and subsequent multiple endocrine neoplasia type 1 endocrine lesions was significantly longer when pituitary disease was the initial manifestation of multiple endocrine neoplasia type 1. Tumors were larger and more invasive and clinical manifestations related to the size of the pituitary adenoma were significantly more frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Normalization of pituitary hypersecretion was much less frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Pituitary tumors in patients with multiple endocrine neoplasia type 1 syndrome tend to be larger, invasive and more symptomatic, and they tend to occur in younger patients when they are the initial presentation of multiple endocrine neoplasia type 1.

Bilateral adrenocortical carcinoma in a patient with multiple endocrine neoplasia type 1 (MEN1) and a novel mutation in the MEN1 gene

The incidence of adrenal involvement in MEN1 syndrome has been reported between 9 and 45%, while the incidence of adrenocortical carcinoma (ACC) in MEN1 patients has been reported between 2.6 and 6%. In the literature data only unilateral development of ACCs in MEN1 patients has been reported. We report a 31 years-old female MEN1-patient, in whom hyperplasia of the parathyroid glands, prolactinoma, non functioning pancreatic endocrine carcinoma and functioning bilateral adrenal carcinomas were diagnosed. Interestingly, a not previously described in the literature data, novel germline mutation (p.E45V) in exon 2 of MEN1 gene, was detected. The association of exon 2 mutation of the MEN1 gene with bilateral adrenal carcinomas in MEN1 syndrome, should be further investigated.

Thymic neuroendocrine tumors in multiple endocrine neoplasia type 1: a comparative study on 21 cases among a series of 761 MEN1 from the GTE (Groupe des Tumeurs Endocrines)

BACKGROUND

Thymic neuroendocrine tumors (Th-NET) present a poor prognosis for patients with multiple endocrine neoplasia type 1 (MEN1). The purpose of this article was to study the clinical, biological, and pathological features of Th-NET in a large cohort of patients with MEN1.

METHODS

The 761-patient MEN1 cohort from the GTE registry was used (Groupe des Tumeurs Endocrines).

RESULTS

The actuarial probability of occurrence was 2.6% (range, 1.3-5.5%) at aged 40 years. All, except one, Th-NET patients were men. Four patients had no other associated lesions. The youngest patient was aged 16 years. Mean age at the time of diagnosis was 42.7 (range, 16.1-67.5) years. The 10-year probability of survival was 36.1% (range, 11.5-62%). Seven patients (33%) belonged to clustered MEN1 families. The spectrum of associated lesions in patients with Th-NET was not statistically different from the spectrum of the remainder of the cohort. Various endocrine markers were high, but none were sensitive or specific enough to be useful for Th-NET detection. CT-scan and MRI were always positive at the time of diagnosis. No particular mutation was found to be associated with Th-NET. Five cases underwent prophylactic thymectomy without success.

CONCLUSIONS

Several end points may be helpful for future guidelines: (1) earlier detection of Th-NET in MEN1 patients is required; (2) screening of both sexes is necessary; (3) a prospective study comparing MRI vs. CT scan in yearly screening for Th-NET is needed; (4) a reinforced screening program must be established for patients who belong to clustered families; and (5) thymectomies must be performed in specialized centers.

Unusual clinical and pathological presentation of a neuroendocrine tumor in a patient with multiple endocrine neoplasia type 1

Neuroendocrine tumors develop in various organs in patients with multiple endocrine neoplasia type 1 (MEN1). Among those, tumors developed in upper gastrointestinal tract, thymus and bronchus have historically been called "carcinoid tumor". Occurrence of "carcinoid tumor" in other region is very rare and molecular pathogenesis of such tumors is unknown. We have experienced a patient with MEN1 who have developed an "ectopic" retroperitoneal neuroendocrine tumor. Genetic analysis of the MEN1 gene in tumor cells revealed a somatic mutation in exon 9 as well as a germline mutation in exon 10. Allele-specific amplification followed by sequence analysis revealed these two mutations exist on the different allele, indicating both alleles are functionally inactivated. Immunohistochemical staining with an anti-menin antibody revealed that wild-type menin is not expressed in tumor cells. Expression of p27(Kip1) protein is not observed in tumor cells, either. These results confirmed the inactivation of the MEN1 gene as a genetic cause of an ectopically developed neuroendocrine tumor in a patient with MEN1.

Multiple endocrine neoplasia type 1

Multiple Endocrine Neoplasia type 1 (MEN1) is a rare autosomal dominant hereditary cancer syndrome presented mostly by tumours of the parathyroids, endocrine pancreas and anterior pituitary, and characterised by a very high penetrance and an equal sex distribution. It occurs in approximately one in 30,000 individuals. Two different forms, sporadic and familial, have been described. The sporadic form presents with two of the three principal MEN1-related endocrine tumours (parathyroid adenomas, entero-pancreatic tumours and pituitary tumours) within a single patient, while the familial form consists of a MEN1 case with at least one first degree relative showing one of the endocrine characterising tumours. Other endocrine and non-endocrine lesions, such as adrenal cortical tumours, carcinoids of the bronchi, gastrointestinal tract and thymus, lipomas, angiofibromas, collagenomas have been described. The responsible gene, MEN1, maps on chromosome 11q13 and encodes a 610 aminoacid nuclear protein, menin, with no sequence homology to other known human proteins. MEN1 syndrome is caused by inactivating mutations of the MEN1 tumour suppressor gene. This gene is probably involved in the regulation of several cell functions such as DNA replication and repair and transcriptional machinery. The combination of clinical and genetic investigations, together with the improving of molecular genetics knowledge of the syndrome, helps in the clinical management of patients. Treatment consists of surgery and/or drug therapy, often in association with radiotherapy or chemotherapy. Currently, DNA testing allows the early identification of germline mutations in asymptomatic gene carriers, to whom routine surveillance (regular biochemical and/or radiological screenings to detect the development of MEN1-associated tumours and lesions) is recommended.

Thymic carcinoid in multiple endocrine neoplasia 1: genotype-phenotype correlation and prevention

Thymic carcinoid is a rare multiple endocrine neoplasia type 1 (MEN1)-associated tumour that is a major cause of death in MEN1 patients. Here, we describe a previously unreported MEN1 family in which two siblings presented with malignant thymic carcinoids. All six siblings share a novel nonsense mutation Q395X on exon 8 of the MEN1 gene. The index patient developed a thymic carcinoid despite an earlier prophylactic transcervical thymectomy, and one other sibling had an incidental malignant thymic carcinoid discovered following prophylactic thymectomy, both cases demonstrating the weakness and strength of this surgical approach. We then review the spectrum of germline MEN1 mutations associated with thymic carcinoids to evaluate the possibility of a genotype-phenotype correlation. In the 22 separate MEN1 families with thymic carcinoids, all but two (91%) have mutations coding for a truncated protein. There is clearly a high prevalence of truncating mutations in MEN1-related thymic carcinoids although when compared with the prevalence of truncating mutations in all reported MEN1 mutations, it is not statistically significant (P = 0.39). Further studies are warranted to evaluate pathways of tumorigenesis of thymic carcinoids with regard to loss of function of menin.

Multiple Endocrine Neoplasia: Spectrum of Radiologic Appearances and Discussion of a Multitechnique Imaging Approach

Multiple endocrine neoplasia (MEN) is characterized by the occurrence of two or more tumors that may be associated with hyperfunction and malignancy. MEN is caused by genetic defects, and two major types, MEN 1 and MEN 2, are recognized. Each type is characterized by the development of tumors within specific endocrine organs. A multidisciplinary approach involving cooperation between endocrinologists, surgeons, oncologists, and radiologists is pivotal for optimizing patient treatment. Imaging plays a vital role in the diagnosis and management of the disease. To contribute effectively, however, the radiologist must understand the range of anatomic and functional imaging modalities used in the assessment of endocrine disorders. In addition, knowledge of the optimal techniques for evaluating the pituitary, thyroid, parathyroid, pancreatic, adrenal, and foregut carcinoid tumors that occur in these MEN syndromes is essential. Finally, an understanding of the spectrum of disease and of the manifestations of each component is crucial for accurate detection, staging, and surveillance in this diverse patient group.

Multiple endocrine neoplasia type I and Cushing's syndrome due to an aggressive ACTH producing thymic carcinoid

Thymic carcinoid in multiple endocrine neoplasia type 1 (MEN 1) is previously reported as a non-ACTH producing tumor. The present case is a 39-year-old man with mortal outcome from thymic carcinoid and Cushing's syndrome with high plasma ACTH. The symptom was first observed at age 29 and was relieved after extended thymectomy, with reduction of ACTH level. The tumor was positive for ACTH, Grimelius silver staining and Chromogranin A. The finding of primary hyperparathyroidism, pituitary adenoma, and a novel germline nonsense mutation (W423X) established the diagnosis of MEN 1. Cushing's syndrome due to ACTH producing thymic carcinoid should be also considered as one phenotype of the MEN 1 spectrum.

The diagnosis and medical management of advanced neuroendocrine tumors

Neuroendocrine tumors (NETs) constitute a heterogeneous group of neoplasms that originate from endocrine glands such as the pituitary, the parathyroids, and the (neuroendocrine) adrenal, as well as endocrine islets within glandular tissue (thyroid or pancreatic) and cells dispersed between exocrine cells, such as endocrine cells of the digestive (gastroenteropancreatic) and respiratory tracts. Conventionally, NETs may present with a wide variety of functional or nonfunctional endocrine syndromes and may be familial and have other associated tumors. Assessment of specific or general tumor markers offers high sensitivity in establishing the diagnosis and can also have prognostic significance. Imaging modalities include endoscopic ultrasonography, computed tomography and magnetic resonance imaging, and particularly, scintigraphy with somatostatin analogs and metaiodobenzylguanidine. Successful treatment of disseminated NETs requires a multimodal approach; radical tumor surgery may be curative but is rarely possible. Well-differentiated and slow-growing gastroenteropancreatic tumors should be treated with somatostatin analogs or alpha-interferon, with chemotherapy being reserved for poorly differentiated and progressive tumors. Therapy with radionuclides may be used for tumors exhibiting uptake to a diagnostic scan, either after surgery to eradicate microscopic residual disease or later if conventional treatment or biotherapy fails. Maintenance of the quality of life should be a priority, particularly because patients with disseminated disease may experience prolonged survival.

Atypical thymic carcinoid and malignant somatostatinoma in type I multiple endocrine neoplasia syndrome: case report

Thymic carcinoid and malignant somatostatinoma are both rare, and their concurrent presence in multiple endocrine neoplasia type 1 (MEN-1) has never been reported in the English literature to date. We present a patient with thymic carcinoid and malignant somatostatinoma in association with MEN-1. The patient eventually died of pulmonary aspergillosis and respiratory failure. Autopsy showed a 16 x 10 x 8-cm thymic carcinoid tumor, parathyroid and adrenal gland hyperplasia, and malignant somatostatinoma of the pancreas with a metastatic tumor over the splenic hilum.

The treatment of sporadic versus MEN1-related pituitary adenomas

The treatment of pituitary tumours strongly depends on their clinical presentation. In general, the treatment aims are reducing tumour volume and/or decreasing hormone hypersecretion. It relies on single or a combination of three different methods: surgery, medication and radiotherapy. The rationale for deciding the treatment are many but include the aggressiveness of the tumour. The aetiologies of sporadic pituitary adenomas are not fully understood. However, several causes have been identified resulting in specific familial phenotypes like multiple endocrine neoplasia type I (MEN1). MEN1 is related to mutations in the MEN1 gene, a tumour suppressor gene localized on chromosome 11q13 and which encodes menin, a 610 amino acid protein. During the last years, an evidence progressively emerged that MEN1-related adenomas were more aggressive and less responsive to therapy than their sporadic counterparts. In this article, we review the differences between sporadic and MEN1-related adenomas and suggest specific ways of treatment and follow-up for MEN1-related tumours.

Prospective study of thymic carcinoids in patients with multiple endocrine neoplasia type 1

Little is known of the natural history of thymic carcinoids in multiple endocrine neoplasia type 1 (MEN1). This is important because in 1993 they were identified as a frequent cause of death, yet only small retrospective studies and case reports exist. We report results of a prospective study of 85 patients with MEN1 evaluated for pancreatic endocrine tumors and followed over a mean of 8 yr with serial chest computed tomography, magnetic resonance imaging (MRI), chest x-ray, and, since 1994, octreoscans [somatostatin receptor scintigraphy (SRS)]. Seven patients (8%) developed thymic carcinoids. Patients with and without carcinoids did not differ in clinical, laboratory, or MEN1 tumor features, except for male gender and the presence of a gastric carcinoid. All thymic tumors were hormonally inactive. Four thymic carcinoids lacked 11q loss of heterozygosity, although it was found in three pancreatic endocrine tumors. Computed tomography and/or MRI were more sensitive than SRS or chest x-ray in detecting tumors initially or with recurrence. All patients underwent resection of the thymic carcinoid, and in all patients followed more than 1 yr, the tumor recurred. Bone metastases developed in two patients and were detected early only on MRI, not SRS. This study provides information on early thymic carcinoids and allows modifications of existing guidelines to be recommended for their diagnosis, surveillance, and treatment.

Primary neuroendocrine tumors of the thymus

Primary neuroendocrine tumors of the thymus are highly aggressive tumors that rarely occur. A little more than 200 cases have been reported, many of which were single case reports. Only a few articles contained modest series from single centers for analysis. A review of 157 cases collected from the major series reported to-date show a clinical pattern with male preponderance (male:female ratio, 3:1) and a mean age of 54 years. Most patients presented with symptoms and signs of local compression. Almost 50% of these tumors were functionally active and were associated with endocrinopathies. Several histologic variants have been described, all with similar ultrastructural features. The biologic behavior of these tumors shows a direct relation to the degree of differentiation. Whenever possible, surgical resection is the treatment of choice as adjuvant therapy is controversial and has been used with variable success. Potential therapies exploit the presence of somatostatin receptors on a variety of these tumors. Use of radiolabeled Octreotide for radionuclide therapy has yielded tumor inhibition in animal models and may have clinical application. Fifty-one percent of the patients survived 3 years, 27% survived 5 years, and less than 10% survived beyond 10 years. Histologic grade, tumor extension, and early detection are the most important factors affecting survival. Other prognostic factors that impact outcome include presence of endocrinopathy, incomplete resectability, nodal status, and presence of distant metastasis.

Ectopic growth hormone-releasing hormone secretion by thymic carcinoid tumour

The case of a 33-year-old-woman with Multiple Endocrine Neoplasia Type 1 (MEN1) syndrome and acromegaly due to ectopic growth hormone-releasing hormone (GHRH) secretion by a thymic carcinoid tumour is reported. Immunohistochemistry revealed positive immunoreactivity for GHRH, vasoactive intestinal polypeptide, somatostatin and alpha-subunit in the tumour cells. A previously undescribed new germ line mutation of the MEN1 protein gene was revealed.

Neuroendocrine carcinoma (carcinoid) of the thymus associated with Cushing's syndrome

Neuroendocrine carcinoma (carcinoid) of the thymus associated with Cushing's syndrome is a rare disease. Recent evidence suggests that these tumors form part of a continuous spectrum ranging from well-differentiated carcinomas to small cell carcinomas. We report two new cases and review the 23 cases reported in the literature since 1972. The different diagnostic modalities are discussed, and an algorithm for the diagnosis of ectopic secretion of adrenocorticotropin (ACTH) is presented. In the future, the advent of radiologic and nuclear imaging as well as more accurate workup should help to diagnose these tumors at an earlier stage and improve the long-term outcome.

Endocrine tumours of the pancreas: review and recent advances

Pancreatic endocrine tumours (PET) are rare but nonetheless important to recognize and treat in a timely fashion. Significant morbidity occurs due to excess secretion of hormones, with all of the PET having some degree of malignant potential. Surgeons must plan directed operative strategies to deal with these tumours and be prepared to undertake aggressive palliative debulking resections if indicated. Somatostatin receptor scintigraphy and endoscopic ultrasound have been particularly helpful in both localizing and staging patients with PET. Other important advances in management include the use of long-acting somatostatin analogues to inhibit hormonal secretion and tumour growth. The possibility of multiple endocrine neoplasia type 1 (MEN-1) should be considered in any patient with a PET. The present article will review the various classes of PET, describe MEN-1 in relation to PET and examine advances in imaging and localization. The role of surgery for PET is also discussed in the present review.

Early surgical intervention and strategy in patients with multiple endocrine neoplasia type 1

Patients with multiple endocrine neoplasia type 1 (MEN-1) are an unusual challenge to the endocrine surgeon. Pituitary disease is often treated without surgery, but nearly all patients will require parathyroidectomy for parathyroid hyperplasia. Subtotal parathyroidectomy can be accomplished with a very low rate of permanent hypoparathyroidism and an acceptable rate of recurrent hyperparathyroidism. The treatment of pancreaticoduodenal disease is quite controversial. Even when associated with the Zollinger-Ellison syndrome, early and aggressive surgical treatment should be considered to influence the hormonal syndrome as well as to address the malignant potential of both pancreatic and duodenal tumours. This includes distal pancreatectomy, enucleation of pancreatic head lesions, and duodenotomy with the resection of gastrinomas. Many patients may be completely cured of the manifestations of their disease. As MEN-1 is an uncommon entity, there are very few prospective, randomized data upon which to base surgical judgements.