Thymic carcinoids in multiple endocrine neoplasia type 1

Current understanding of pathogenetic mechanisms in neuroendocrine neoplasms

INTRODUCTION

Despite the fact that important advances in research on neuroendocrine neoplasms (NENs) have been made, consistent data about their pathogenetic mechanism are still lacking. Furthermore, different primary sites may recognize different pathogenetic mechanisms.

AREAS COVERED

This review analyzes the possible biological and molecular mechanisms that may lead to NEN onset and progression in different organs. Through extensive research of the literature, risk factors including hypercholesterolemia, inflammatory bowel disease, chronic atrophic gastritis are evaluated as potential pathogenetic mechanisms. Consistent evidence is available regarding sporadic gastric NENs and MEN1 related duodenopancreatic NENs precursor lesions, and genetic-epigenetic mutations may play a pivotal role in tumor development and bone metastases onset. In lung neuroendocrine tumors (NETs), diffuse proliferation of neuroendocrine cells on the bronchial wall (DIPNECH) has been proposed as a premalignant lesion, while in lung neuroendocrine carcinoma nicotine and smoke could be responsible for carcinogenic processes. Also, rare primary NENs such as thymic (T-NENs) and Merkel cell carcinoma (MCC) have been analyzed, finding different possible pathogenetic mechanisms.

EXPERT OPINION

New technologies in genomics and epigenomics are bringing new light to the pathogenetic landscape of NENs, but further studies are needed to improve both prevention and treatment in these heterogeneous neoplasms.

Thymic Carcinoid in a Patient with Concurrent Manifestations of Multiple Endocrine Neoplasia Type 1

Thymic carcinoid tumours, especially in the context of multiple endocrine neoplasia type 1 (MEN 1), present significant clinical challenges due to their rarity and aggressive nature. This case report describes a complex patient with MEN 1, who suffered from multiple manifestations of the disease, including thymic carcinoid. The tumour was initially resected and treated with adjuvant radiotherapy. Due to slow progression over the years, the tumour was treated with two lines of chemotherapy before the patient succumbed to progressive disease. There is currently limited evidence favoring any specific medical treatment for thymic carcinoid.

Continuing challenges of primary neuroendocrine tumours of the thymus: A concisereview

Primary neuroendocrine tumours of the thymus (NETTs) are exceedingly rare tumours, usually presenting around mid-life, which have a propensity towards males and smokers. They are seen more often in those with MEN-1, but multiple different genetic mutations have been found to be involved in the tumorigenesis of NETTs. Histologically, NETTs are classified according to number of mitoses, the presence of necrosis, and the presence or absence of small cell features. NETTs display a wide spectrum of behavior, and they can be incidentally found on chest imaging, on screening in MEN-1, or present with symptoms of local compression. Advanced disease and paraneoplastic syndromes are common. CT-, PET/CT-, MRI-scans, and somatostatin receptor scintigraphy are the imaging modalities of choice both for the initial assessment as well as for monitoring after treatment. For patients with localized disease, complete surgical resection with lymphadenectomy provides the best chance of long-term, disease-free survival, and can be achieved through either an open or thoracoscopic approach. While chemotherapy-regimens based on platinum, taxane, and temozolomide are used most often, the optimum chemotherapy regimen in the adjuvant and palliative settings remains unclear, as does the role of radiotherapy. Ongoing research on the most effective use of somatostatin analogues, peptide receptor radionuclide therapy (PPRT), kinase inhibitors and immunotherapy in patients with other types of advanced neuroendocrine tumours may lead to further treatment options for NETTs in the future.

Thymic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1

OBJECTIVE

MEN1 is associated with an increased risk of developing tumors in different endocrine organs. Neuroendocrine tumors of the thymus (TNETs) are very rare but often have an aggressive nature. We evaluated patients with MEN1 and TNET in three university hospitals in Finland.

DESIGN/METHODS

We evaluated patient records of 183 MEN1-patients from three university hospitals between the years 1985-2019 with TNETs. Thymus tumor specimens were classified according to the new WHO 2021 classification of TNET. We collected data on treatments and outcomes of these patients.

RESULTS

There were six patients (3.3%) with MEN1 and TNET. Five of them had the same common gene mutation occurring in Finland. They originated from common ancestors encompassing two pairs of brothers from sequential generations. The mean age at presentation of TNET was 44.7 ± 11.9 years. TNET was classified as atypical carcinoid (AC) in five out of six patients. One patient had a largely necrotic main tumor with very few mitoses and another nodule with 25 mitoses per 2 mm², qualifying for the 2021 WHO diagnosis of large cell neuroendocrine carcinoma (LCNEC). In our patients, the 5-year survival of the TNET patients was 62.5% and 10-year survival 31.3%.

CONCLUSION

In this study, TNETs were observed in one large MEN1 founder pedigree, where an anticipation-like earlier disease onset was observed in the most recent generation. TNET in MEN1 patients is an aggressive disease. The prognosis can be better by systematic screening. We also show that LCNEC can be associated with TNET in MEN1 patients.

Ectopic Cushing's syndrome due to thymic neuroendocrine tumours: a systematic review

Knowledge of ectopic Cushing's syndrome (CS) due to thymic neuroendocrine tumours (NETs) comes from short series or single cases. Our aim is to perform a systematic review using PubMed, Embase, Scopus, Ovid Medline and Biosis Previews of all cases with ectopic CS due to thymic NETs reported in the last 40 years and describe one illustrative patient attended in our institution. Search of literature: From 162 patients, 58.6% were male and mean age was 34.6 ± 13.9 years-old. Median of symptoms until diagnosis was 6 [2-24] months and 62% had aggressive CS. Imaging was positive in 93.7% (chest X-ray), 97.8% (computed tomography), 80.7% (somatostatin receptor scintigraphy) and median tumour size was 47 [25-68.5] mm. At presentation, 18% had localized disease, 26.2% locally invasive and 55.7% advanced. Eighty-eight present underwent surgery and histological subtypes were atypical (46.7%), typical (30.4%) and carcinoma (21.7%). Tumour persisted or recurred in 70.1%, 63% received radiotherapy and 45.2% chemotherapy. Follow-up median was 26.6 [14.5-57.5] months and mortality was reported in 35.8% with median survival of 38 [19-60] months. MEN-1 mutation was referred in 3.1%. Comparatively, carcinomas had aggressive CS more frequently while atypical showed advanced disease more often. In conclusion, thymic NETs causing ectopic CS are presented as aggressive hypercortisolism in the middle aged population. The disease is commonly extended at diagnosis and persists or recurs after surgery in most patients with a short term high mortality.

Two distinct classes of thymic tumors in patients with MEN1 show LOH at the MEN1 locus

Patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome carry germline heterozygous loss-of-function mutations in the MEN1 gene which predisposes them to develop various endocrine and non-endocrine tumors. Over 90% of the tumors show loss of heterozygosity (LOH) at chromosome 11q13, the MEN1 locus, due to somatic loss of the wild-type MEN1 allele. Thymic neuroendocrine tumors (NETs) or thymic carcinoids are uncommon in MEN1 patients but are a major cause of mortality. LOH at the MEN1 locus has not been demonstrated in thymic tumors. The goal of this study was to investigate the molecular aspects of MEN1-associated thymic tumors including LOH at the MEN1 locus and RNA-sequencing (RNA-Seq) to identify genes associated with tumor development and potential targeted therapy. A retrospective chart review of 294 patients with MEN1 germline mutations identified 14 patients (4.8%) with thymic tumors (12 thymic NETs and 2 thymomas). LOH at the MEN1 locus was identified in 10 tumors including the 2 thymomas, demonstrating that somatic LOH at the MEN1 locus is also the mechanism for thymic tumor development. Unsupervised principal component analysis and hierarchical clustering of RNA-Seq data showed that thymic NETs formed a homogenous transcriptomic group separate from thymoma and normal thymus. KSR2 (kinase suppressor of Ras 2), that promotes Ras-mediated signaling, was abundantly expressed in thymic NETs, a potential therapeutic target. The molecular insights gained from our study about thymic tumors combined with similar data from other MEN1-associated tumors may lead to better surveillance and treatment of these rare tumors.

Diagnostic Challenges in Fine-Needle Aspiration Cytology of Mediastinal Tumors and Lesions

CONTEXT.—

Mediastinal tumors/lesions are frequently encountered in daily cytopathology practice. These lesions are accessible through endoscopic/endobronchial ultrasound-guided or computed tomography-guided fine-needle aspiration cytology and represent a wide range of primary and metastatic tumors. This often poses diagnostic challenges because of the complexity of the mediastinal anatomic structures. Tumors metastatic to mediastinal lymph nodes represent the most common mediastinal lesions and must be differentiated from primary lesions.

OBJECTIVE.—

To provide an updated review on the fine-needle aspiration cytology of mediastinal tumors/lesions, with an emphasis on diagnostic challenges. This review encompasses thymic epithelial neoplasms, mediastinal lymphoproliferative disorders, germ cell tumors, neuroendocrine tumors, soft tissue tumors, and metastatic tumors. Differential diagnoses; useful ancillary studies, including targeted immunohistochemical panels; and diagnostic pitfalls are discussed.

DATA SOURCES.—

Data were gathered from a PubMed search of peer-reviewed literature on mediastinal tumors. Data were also collected from the authors' own practices.

CONCLUSIONS.—

Fine-needle aspiration cytology plays a vital role in evaluation of mediastinal lesions. Being familiar with the clinical and cytomorphologic features of these lesions, appropriately triaging the diagnostic material for ancillary testing, and correlating with radiologic findings are important in arriving at correct diagnoses and guiding management.

New therapies for patients with multiple endocrine neoplasia type 1

In 1953, for the first time, Paul Wermer described a family presenting endocrine gland neoplasms over several generations. The transmission was autosomal dominant and the penetrance was high. Forty years later in 1997, the multiple endocrine neoplasia type 1 (MEN1) gene was sequenced, thus enabling diagnosis and early optimal treatment. Patients carrying the MEN1 gene present endocrine but also non-endocrine tumors. Parathyroid, pancreatic and pituitary impairment are the three main types of endocrine involvement. The present article details therapeutic management of hyperparathyroidism, neuroendocrine pancreatic tumors and pituitary adenomas in patients carrying the MEN1 gene. Significant therapeutic progress has in fact been made in the last few years. As concerns the parathyroid glands, screening of family members and regular monitoring of affected subjects now raise the question of early management of parathyroid lesions and optimal timing of parathyroid surgery. As concerns the duodenum-pancreas, proton-pump inhibitors are able to control gastrin-secreting syndrome, reducing mortality in MEN1 patients. Mortality in MEN1 patients is no longer mainly secondary to uncontrolled hormonal secretion but to metastatic (mainly pancreatic) disease progression. Tumor risk requires regular monitoring of morphological assessment, leading to iterative pancreatic surgery in a large number of patients. Finally, pituitary adenomas in MEN1 patients are traditionally described as aggressive, invasive and resistant to medical treatment. However, regular pituitary screening showed them to be in fact infra-centimetric and non-secreting in the majority of patients. Consequently, it is necessary to regularly monitor MEN1 patients, with regular clinical, biological and morphological work-up. Several studies showed that this regular monitoring impairs quality of life. Building a relationship of trust between patients and care provider is therefore essential. It enables the patient to be referred for psychological or psychiatric care in difficult times, providing long-term support and preventing any breakdown in continuity of care.

Molecular Pathology of Well-Differentiated Pulmonary and Thymic Neuroendocrine Tumors: What Do Pathologists Need to Know?

Thoracic (pulmonary and thymic) neuroendocrine tumors are well-differentiated epithelial neuroendocrine neoplasms that are classified into typical and atypical carcinoid tumors based on mitotic index cut offs and presence or absence of necrosis. This classification scheme is of great prognostic value but designed for surgical specimens, only. Deep molecular characterization of thoracic neuroendocrine tumors highlighted their difference with neuroendocrine carcinomas. Neuroendocrine tumors of the lung are characterized by a low mutational burden, and a high prevalence of mutations in chromatin remodeling and histone modification-related genes, whereas mutations in genes frequently altered in neuroendocrine carcinomas are rare. Molecular profiling divided thymic neuroendocrine tumors into three clusters with distinct clinical outcomes and characterized by a different average of copy number instability. Moreover, integrated histopathological, molecular and clinical evidence supports the existence of a grey zone category between neuroendocrine tumors (carcinoid tumors) and neuroendocrine carcinomas. Indeed, cases with well differentiated morphology but mitotic/Ki-67 indexes close to neuroendocrine carcinomas have been increasingly recognized. These are characterized by specific molecular profiles and have an aggressive clinical behavior. Finally, thoracic neuroendocrine tumors may arise in the background of genetic susceptibility, being MEN1 syndrome the well-defined familial form. However, pathologists should be aware of rarer germline variants that are associated with the concurrence of neuroendocrine tumors of the lung or their precursors (such as DIPNECH) with other neoplasms, including but not limited to breast carcinomas. Therefore, genetic counseling for all young patients with thoracic neuroendocrine neoplasia and/or any patient with pathological evidence of neuroendocrine cell hyperplasia-to-neoplasia progression sequence or multifocal disease should be considered.

Recent advances and conceptual changes in the classification of neuroendocrine tumors of the thymus

Neuroendocrine tumors of the thymus (TNET) are exceedingly rare neoplasms. Their histomorphology is identical to neuroendocrine tumors elsewhere in the body (in particular the lungs) and bears no similarity with thymomas and thymic carcinomas. Recent molecular findings have profoundly changed our perception of these tumors and may impact future histological classification systems.

Rare Acute Presentation of a Low-Grade Thymic Neuroendocrine Tumor

Primary neuroendocrine tumor (NET) of the thymus is very rare. Here we report an unusual presentation of grade-I typical thymic NET in a 63-year-old female who presented with signs and symptoms of congestive heart failure (CHF) due to the mass effect from the huge tumor. A computed tomography (CT) scan of the chest revealed a mediastinal mass measuring 16.4 x 12 x 15.3 cm displacing most of the left lung parenchyma, with mass effect on the heart, and encasing the ascending aorta and main pulmonary trunk. Pathology report from the thymic mass biopsy showed tumor cells strongly expressing synaptophysin, chromogranin A, and cluster of differentiation (CD)56 markers. The diagnosis was consistent with grade-I typical thymic NET based on low Ki-67 and morphology. The patient was not in agreement for acute surgery or oncological treatment options. Thus, the plan was made to embolize the arteries from the right coronary artery that were feeding the mass in an effort to shrink the size with goals of future surgical resection. However, given the advanced stage of the diagnosis with mass effect on the heart and the patient's reluctance to consider the main definitive treatment options, the prognosis was extremely poor and the patient eventually passed away.

p.L105Vfs mutation in a family with thymic neuroendocrine tumor combined with MEN1: a case report

Background

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disorder arising from mutations of the MEN1 tumor suppressor gene on chromosome 11q13; MEN1 is characterized by the development of neuroendocrine tumors, including those of the parathyroid, gastrointestinal endocrine tissue and anterior pituitary. Additionally, thymic neuroendocrine tumors in MEN1 are also rarely reported.

Case presentation

This case report observed a family that presented with MEN1 p.L105Vfs mutation, and two of the family members had been diagnosed with thymic neuroendocrine tumor combined with MEN1. To the best of our knowledge, this is the first time such a mutation in the MEN1 gene has been reported. The proband presented with thymic neuroendocrine tumor, parathyroid adenoma and rectum adenocarcinoma. The son of the proband presented with thymic neuroendocrine tumor, gastrinoma, hypophysoma and parathyroid adenoma. Genetic testing revealed the frameshift mutation p.L105Vfs, leading to the identification of one carrier in the pedigree (the patient’s younger sister). The proband then underwent parathyroidectomy at the age of 26 years (in 1980) for a parathyroid adenoma. Subsequently, the patient underwent thymectomy, radiotherapy and chemotherapy. The patient is now 64 years old, still alive and still undergoing Lanreotide therapy.

Conclusion

Thymic neuroendocrine MEN1 is rare, but it accounts for almost 20% of MEN1-associated mortality. Consequently, we should focus on regular clinical screening of the thymus in MEN1 patients.

Primary Neuroendocrine Tumor of the Thymus: Radiological and Pathological Correlation

Primary neuroendocrine tumors of the thymus are extremely rare. In this report, we describe a case of a 69 year-old man with an intermediate grade thymic neuroendocrine tumor. The radiologic and histopathologic features of thymic neuroendocrine tumors are discussed with reference to relevant literature.

A novel germline mutation at exon 10 of MEN1 gene: a clinical survey and positive genotype-phenotype analysis of a MEN1 Italian family, including monozygotic twins

CONTEXT

Clinical phenotype variability in MEN1 syndrome exists and evidence for an established genotype-phenotype is lacking. However, a higher aggressiveness of MEN1-associated gastro-entero-pancreatic (GEP) (neuro)endocrine tumours (NETs) tumours has been reported when MEN1 gene truncating mutations are detected. We found a novel germline truncating mutation of MEN1 gene at exon 10 in a subject with an aggressive clinical behavior of GEP-NETs. Successively, other two mutant-affected familial members have been identified.

OBJECTIVE

The aim of this observational study was to investigate genotype-phenotype correlation in these three members, with attention to GPE-NETs behavior over the years.

DESIGN

The genetic and clinical data obtained and the follow-up screening program (2012-2016) were according to the International Guidelines in a multidisciplinary academic reference center. The familial history collected strongly suggested MEN1 GEP-NETs in at least other four members from different generations.

PATIENTS

Three MEN1 patients (aged 30-69 years at MEN1 diagnosis) were clinically screened for MEN1 GEP-NETs, both functioning and nonfunctioning.

METHODS

Biochemical, imaging, and nuclear medicine tests and fine-needle agobiopsy were performed, depending on found/emerging clinical symptoms/biochemical abnormalities, and made when necessary.

RESULTS

Our clinical survey found strong genotype-phenotype correlation with aggressive MEN1 GEP-NETs (G1, G2-NETs, and multiple ZES/gastrinomas) over the years. The familial history strongly suggested ZES/gastrinoma in progenitors from previous generations.

CONCLUSIONS

This novel MEN1 truncating mutation correlates with an aggressive evolution and behavior of MEN1 GEP-NETs in studied affected subjects, confirming the need for MEN1 individuals to be evaluated by a skilled multidisciplinary team, as also stated by International Guidelines.

Coexisting Thymic and Pulmonary Carcinoid Tumors Associated with Multiple Endocrine Neoplasia Type1

An anterior mediastinal tumor was detected in a 45-year-old female during a medical checkup. Chest computed tomography (CT) showed the anterior mediastinal tumor and a pulmonary tumor in the right lower lobe. Furthermore, tumors of the parathyroid gland, pancreas, and pituitary gland were also detected. She was clinically diagnosed with multiple endocrine neoplasia type1 (MEN1). The patient underwent extended thymectomy combined with mediastinal lymph node dissection and wedge resection of the lung including the right pulmonary lesion via a median sternotomy. We diagnosed the patient with an atypical carcinoid tumor of the thymus, a typical pulmonary carcinoid tumor.

An assessment of 18 F-FDG PET/CT for thoracic screening and risk stratification of pulmonary nodules in multiple endocrine neoplasia type 1

CONTEXT

Bronchopulmonary neuroendocrine tumours (bpNETs) and thymic carcinoid (ThC) are features of multiple endocrine neoplasia type 1 (MEN 1), and surveillance guidelines recommend periodic thoracic imaging. The optimal thoracic imaging modality and screening frequency remain uncertain as does the prognosis of small lung nodules when identified.

OBJECTIVES

To evaluate fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸ F-FDG PET/CT) for identification and prognostic assessment of thoracic lesions in MEN 1.

DESIGN

Retrospective observational study.

SETTING AND PARTICIPANTS

Fifty consecutive MEN 1 patients undergoing screening with ¹⁸ F-FDG PET/CT at a tertiary referral hospital between July 2011 and December 2016.

INTERVENTIONS

¹⁸ F-FDG PET/CT.

OUTCOME MEASURES

Pulmonary and thymic lesion prevalence, size, functional characteristics and behaviour.

RESULTS

Thirteen patients (26.0%) exhibited pulmonary nodules with multiple nodules identified in nine (18.0%). An asymptomatic 31 mm FDG-avid ThC was identified in one patient (2%). Of the 13 patients with pulmonary nodules, four (8.0%) exhibited 13 FDG-avid nodules (mean size 10.1 ± 9.1 mm), and nine (18.0%) demonstrated 26 FDG nonavid nodules (mean size 6.9 ± 5.8 mm). All FDG-avid lesions increased in size vs 11 (42.3%) FDG nonavid lesions (P = .0004). For FDG-avid and nonavid nodules, the median doubling time was 24.2 months (IQR 11.4-40.7) and 48.6 months (IQR 37.0-72.2), respectively. Nodule resection was undertaken in two patients, typical bronchial carcinoid diagnosed in one (FDG nonavid) and metastatic renal cell carcinoma in the second (FDG avid).

CONCLUSION

Thoracic imaging with ¹⁸ F-FDG PET/CT effectively identifies pulmonary nodules and ThC. FDG-avid pulmonary lesions are significantly more likely to progress than nonavid lesions.

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).

A case of madness resulting in a fortunate outcome; case report of a psychotic break as a result of cortisol secreting thymic neuroendocrine thymic tumor

Representing a mere 2–5% of the total thymic malignancies and 0.4% of total carcinoid tumors, primary thymic neuroendocrine tumors (NETs) are the zebras of the thymic neoplasms. They were initially characterized as ‘epithelial thymomas’; later, the term carcinoid tumors was coined by Rosai and Higa. These tumors are highly unpredictable in their presentation and prognosis. Coupled with variable clinical presentation, rare pathologic diagnosis and absence of diagnostic and prognostic parameters, it is a challenge for both patients and clinicians. Treatment entails local definitive therapy, symptom control and systemic chemoradiation given either pre or post operatively based on staging and resectability. We hereby report a peculiar case of psychosis that likely resulted from one such rare tumor.

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.

Novel association of MEN1 gene mutations with parathyroid carcinoma

Inactivating mutations of the multiple endocrine neoplasia 1 (MEN1) gene cause MEN1 syndrome, characterized by primary hyperparathyroidism (pHPT), and parathyroid and gastro-entero-pancreatic pituitary tumors. At present, only 14 cases of malignant parathyroid tumor have been associated with the syndrome, with 6 cases carrying an inactivating mutation of the MEN1 gene. The present study presents the case of a 48-year-old female who presented with multigland pHPT and multiple pancreatic lesions. The patient underwent surgery several times for the excision of parathyroid hyperplasia, carcinoma and adenoma. The MEN1 gene was screened, revealing three variants (in cis) at the intron/exon 3 boundary (IVS2-3G>C, c.497A>T and c.499G>T) detected on the DNA of the proband, not shared by her relatives. RNA sequencing revealed that the IVS2-3C>G variant caused the skipping of the exon 3. Therefore, the present study reports on a novel rare association of MEN1 syndrome and parathyroid carcinoma. The reported splicing mutation was previously identified in subjects who always developed malignant lesions; thus, a possible genotype-phenotype association may be considered.

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.

Imaging in multiple endocrine neoplasia type 1: recent studies show enhanced sensitivities but increased controversies

In multiple endocrine neoplasia type 1 (MEN1) patients, a number of recent studies compare the ability of different, new imaging modalities to existing modalities to localize the important neuroendocrine tumors (NETs) that contribute to their decreased life expectancy (pancreatic NETs [pNETs] and thymic carcinoids). These included the use of ⁶⁸Ga-DOTATOC-PET/CT, endoscopic ultrasound and MRI. The current paper analyzes these results in light of current guidelines and controversies involved in the treatment/management of MEN1 patients. Particular attention is paid to results in these studies with thymic carcinoids and nonfunctional pNETs/gastrinomas, which recent studies show are particularly important in determining long-term survival. These studies show a number of promising imaging results but also raise a number of controversies, which will need to be addressed both in their use initially and for serial studies in these patients.

When and how should patients with multiple endocrine neoplasia type 1 be screened for thymic and bronchial carcinoid tumours?

Patients with multiple endocrine neoplasia type 1 (MEN1) are commonly evaluated for clinical manifestations of this syndrome with the rationale that early diagnosis and adequate treatment will result in improved survival and quality of life. Thymic and bronchial carcinoid tumours are uncommon but important manifestations of MEN1. Current practice guidelines recommend evaluation with computed tomography or magnetic resonance imaging scan of the chest every 1-2 years to detect these neoplasms. However, the certainty that patients will be better off (increased survival or quality of life) as a result of this case detection strategy is based on evidence at moderate-high risk of bias that yields only imprecise results of indirect relevance to these patients. In order to improve the care that patients with MEN1 receive, co-ordinated efforts from different stakeholders are required so that large, prospective, multicentre studies evaluating patient important outcomes are carried out.

Multiple Endocrine Neoplasia: Genetics and Clinical Management

Early diagnosis of multiple endocrine neoplasia (MEN) syndromes is critical for optimal clinical outcomes; before the MEN syndromes can be diagnosed, they must be suspected. Genetic testing for germline alterations in both the MEN type 1 (MEN1) gene and RET proto-oncogene is crucial to identifying those at risk in affected kindreds and directing timely surveillance and surgical therapy to those at greatest risk of potentially life-threatening neoplasia. Pancreatic, thymic, and bronchial neuroendocrine tumors are the leading cause of death in patients with MEN1 and should be aggressively considered by at least biannual computed tomography imaging.

Familial syndromes associated with neuroendocrine tumours

Neuroendocrine tumours may be associated with familial syndromes. At least eight inherited syndromes predisposing to endocrine neoplasia have been identified. Two of these are considered to be major factors predisposing to benign and malignant endocrine tumours, designated multiple endocrine neoplasia type 1 and type 2 (MEN1 and MEN2). Five other autosomal dominant diseases show more heterogeneous clinical patterns, such as the Carney complex, hyperparathyroidism-jaw tumour syndrome, Von Hippel-Lindau syndrome (VHL), neurofibromatosis type 1 (NF1) and tuberous sclerosis. The molecular and cellular interactions underlying the development of most endocrine cells and related organs represent one of the more complex pathways not yet to be deciphered. Almost all endocrine cells are derived from the endoderm and neuroectoderm. It is suggested that within the first few weeks of human development there are complex interactions between, firstly, the major genes involved in the initiation of progenitor-cell differentiation, secondly, factors secreted by the surrounding mesenchyme, and thirdly, a series of genes controlling cell differentiation, proliferation and migration. Together these represent a formula for the harmonious development of endocrine glands and tissue.

Thymic and Bronchial Carcinoid Tumors in Multiple Endocrine Neoplasia Type 1: The Mayo Clinic Experience from 1977 to 2013

The clinical features of thymic carcinoid (TC) and bronchial carcinoid (BC) tumors as part of multiple endocrine neoplasia type 1 (MEN1) have been rarely described and their importance in clinical practice is debated. The objective of this study was to describe the clinical presentation and outcome of this uncommon manifestation of MEN1 in a tertiary care center setting. We present the clinical features of patients with MEN1 and either TC or BC evaluated at the Mayo Clinic from 1977 to 2013. A total of 348 patients with MEN1 were evaluated and the prevalence of TC was 2.0% (n = 7) and of BC 4.9% (n = 17). The majority of the patients with BC were men (61%) diagnosed on routine screening (77%) and BC was not the confirmed cause of death in any patient. In contrast, TC patients were all men and during follow-up 43% died due to TC complications. We conclude that TC and BC tumors are uncommon, but important components of MEN1. BC were most commonly diagnosed during routine screening and associated with an indolent course. TC were predominantly seen in men and associated with a more aggressive behavior.

The genetics of endocrine neoplasia

The hereditary endocrine neoplasias are characterized by the development of benign or malignant tumors in more than one endocrine tissue. These tumors typically occur at a younger age than sporadic endocrine tumors and follow an autosomal dominant pattern of inheritance. Because of the age-related penetrance and extreme phenotypic variability both within and between families, clinicians cannot always rely on the family history to make the diagnosis. Recognition of the features of a hereditary endocrine syndrome can allow for appropriate and timely risk assessment, genetic counseling and genetic testing, and identification of at-risk family members who may benefit from early and regular screening.

Natural course and survival of neuroendocrine tumors of thymus and lung in MEN1 patients

CONTEXT

The natural course and survival of neuroendocrine tumors (NETs) of thymus (Th) and lung in multiple endocrine neoplasia type 1 (MEN1) patients are still unknown.

OBJECTIVE

Our objective was to assess prevalence, tumor growth, and survival of Th and lung NETs in an unselected MEN1 population with long-term follow-up.

DESIGN

This was an observational study.

PATIENTS AND METHODS

A longitudinal study was performed using the Dutch national MEN1 database, including >90% of the Dutch MEN1 population >16 years of age. Patients under care of the Dutch University Medical Centers (1990-2011) (n = 323) were included.

MAIN OUTCOME MEASURES

The prevalence and survival of Th and lung NETs were assessed. Linear mixed-models analysis was applied to assess tumor growth with age as a possible confounder and gender, genotype and baseline tumor size as possible effect modifiers.

RESULTS

Th NETs occurred in 3.4% of patients, almost exclusively in males with a 10-year survival of 25% (95% confidence interval = 8%-80%). A thoracic computed tomography scan was available in 188 patients (58.2%). A lung NET was identified in 42 patients (13.0%) with a 10-year survival of 71.1% (95% confidence interval = 51%-100%). Tumor volume of lung NETs increased 17% per year (P < .001) (tumor doubling time 4.5 years). Tumor doubling time in males was 2.5 vs 5.5 years in females (P = .05). Lung NET growth was not associated with genotype or with baseline tumor size (<1 vs ≥1 cm).

CONCLUSION

In MEN1 patients, Th NETs almost exclusively occurred in males and had a very low prevalence and a high mortality. Lung NETs occurred more often than previously thought, had an indolent course, and occurred equally in both sexes. Tumor growth in males was double compared with female patients.

Thoracic and duodenopancreatic neuroendocrine tumors in multiple endocrine neoplasia type 1: natural history and function of menin in tumorigenesis

Mutations of the multiple endocrine neoplasia type 1 (MEN1) gene lead to loss of function of its protein product menin. In keeping with its tumor suppressor function in endocrine tissues, the majority of the MEN1-related neuroendocrine tumors (NETs) show loss of heterozygosity (LOH) on chromosome 11q13. In sporadic NETs, MEN1 mutations and LOH are also reported, indicating common pathways in tumor development. Prevalence of thymic NETs (thNETs) and pulmonary carcinoids in MEN1 patients is 2-8%. Pulmonary carcinoids may be underreported and research on natural history is limited, but disease-related mortality is low. thNETs have a high mortality rate. Duodenopancreatic NETs (dpNETs) are multiple, almost universally found at pathology, and associated with precursor lesions. Gastrinomas are usually located in the duodenal submucosa while other dpNETs are predominantly pancreatic. dpNETs are an important determinant of MEN1-related survival, with an estimated 10-year survival of 75%. Survival differs between subtypes and apart from tumor size there are no known prognostic factors. Natural history of nonfunctioning pancreatic NETs needs to be redefined because of increased detection of small tumors. MEN1-related gastrinomas seem to behave similar to their sporadic counterparts, while insulinomas seem to be more aggressive. Investigations into the molecular functions of menin have led to new insights into MEN1-related tumorigenesis. Menin is involved in gene transcription, both as an activator and repressor. It is part of chromatin-modifying protein complexes, indicating involvement of epigenetic pathways in MEN1-related NET development. Future basic and translational research aimed at NETs in large unbiased cohorts will clarify the role of menin in NET tumorigenesis and might lead to new therapeutic options.

Tumor genetics and survival of thymic neuroendocrine neoplasms: a multi-institutional clinicopathologic study

Thymic neuroendocrine tumors (TNET) are rare primary epithelial neoplasms of the thymus. This study aimed to determine clinically relevant parameters for their classification and for therapeutic decisions. We performed a comprehensive histological, clinical, and genetic study of 73 TNET cases (13 thymic typical carcinoids [TTC], 40 thymic atypical carcinoids [TAC], and 20 high-grade neuroendocrine carcinomas [HGNEC] of the thymus), contributed by multiple institutions. The mean number of chromosomal imbalances per tumor was 0.8 in TTC (31% aberrant cases) versus 1.1 in TAC (44% aberrant cases) versus 4.7 in HGNEC (75% aberrant cases). Gains of 8q24 (MYC gene locus) were the most frequent alteration and one of the overlapping features between carcinoids and HGNEC. The 5-year survival rates for TTC, TAC, and HGNEC were 100, 60, and 30%. The 10-year survival rates for TTC and TAC were 50 and 30% (P = 0.002). Predictive mitotic cut-off values for TTC versus TAC were 2.5 per 10 high-power fields (HPF; indicating a higher death rate, P = 0.062) and 15 per 10 HPF (indicating higher risk of recurrence, P = 0.036) for separating HGNEC from TAC. We conclude that the current histopathologic classifications of TNET reflect tumor biology and provide important information for therapeutic management.

Thymic neuroendocrine carcinoma producing ectopic adrenocorticotropic hormone and Cushing's syndrome

Neuroendocrine carcinoma of the thymus, previously termed thymic carcinoid, is a rare clinical entity. Rarer still are such cases presenting with endocrinopathies. We report a case of thymic neuroendocrine carcinoma presenting with ectopic adrenocorticotroic hormone production and resultant Cushing's syndrome.

Rapid development of thymic neuroendocrine carcinoma despite transcervical thymectomy in a patient with multiple endocrine neoplasia type 1

Thymic neuroendocrine (NE) tumors are a rare manifestation of multiple endocrine neoplasia syndrome type 1 (MEN-1). They are malignant and aggressive tumors and form a major cause of mortality in MEN-1. Transcervical thymectomy (TCT) at the time of parathyroid surgery for primary hyperparathyroidism (PHPT) in MEN-1 usually prevents thymic NE tumors. We report a 56-year-old nonsmoker male with sporadic MEN-1 who presented with thymic NE carcinoma developing rapidly within a span of 8 months after subtotal parathyroidectomy and TCT for PHPT. We present a brief review of literature on this rare NE malignancy, focusing on its occurrence despite TCT. This case highlights the fact that thymic NE carcinoma may develop even after TCT in MEN-1. Regular surveillance for these aggressive thymic NE tumors is mandatory even after TCT in MEN-1 setting.

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 neuroendocrine tumour in multiple endocrine neoplasia type 1: female patients are not rare exceptions

OBJECTIVE

Thymic neuroendocrine tumour (Th-NET) occurs in 2-5% of patients with MEN1 and has high malignant potency accompanying recurrence and distant metastasis. While Th-NET is recognized to develop predominantly in men and heavy smokers, a number of female patients have been reported in the literature. The objective of this study is to clarify the clinical features of MEN1 patients with Th-NET using database analysis.

DESIGN/PATIENTS

Clinical data of patients with Th-NET were extracted and analysed from a recently constructed database of Japanese MEN1 patients.

RESULTS

Among 560 registered cases, Th-NET was seen in 28 (5·0%) patients. Of note, 36% of patients (10/28) were women; only one patient among those was a smoker and another six patients were non-smokers. Age at diagnosis of Th-NET and MEN1, tumour size, prevalence of other MEN1-related tumours did not differ between male and female patients, and 10-year survival probability was 0·271 ± 0·106.

CONCLUSIONS

Although the prevalence of Th-NET in women (3·2%) is significantly lower than that in men (7·6%), a considerable proportion of female patients develop Th-NET. Given that Th-NET is a major determinant of life expectancy of patients, our results alert clinicians who treat patients with MEN1 that surveillance of Th-NET is essential even for female patients without a smoking habit.

Neuroendocrine ACTH-producing tumor of the thymus--experience with 12 patients over 25 years

CONTEXT

ACTH-producing neuroendocrine tumor (NET) of the thymus is a rare cause of Cushing's syndrome (CS). The literature consists mainly of isolated case reports.

PATIENTS

We studied 12 cases (eight males and four females) diagnosed between 1986 and 2010 with CS and thymic NET who underwent surgical resection.

MAIN OUTCOME MEASURES

We measured time from onset of CS to diagnosis of thymic NET, tumor size, histological grade, time to recurrence, and survival and performed a meta-analysis of other published cases of CS associated with thymic NET.

RESULTS

Eleven of 12 patients presented with classic features of CS at a median age of 21 yr (range, 7-51). Four were children. The 24-h urine free cortisol was greater than 16-fold of normal, and biochemical testing was consistent with ectopic ACTH production in all 11. Another patient presenting with pulmonary embolus had a thymic mass and was later diagnosed with CS. All patients underwent thymectomy, and nine of 10 tumors exhibited positive ACTH immunochemistry. Median tumor diameter was 5 cm (range, 1-11.5). Six patients recurred 20-28 months after surgery with metastases to mediastinal lymph nodes (n = 5), bone (n = 5), liver (n = 1), parotid gland (n = 1), and breast (n = 1). Four of five patients treated with radiation therapy also received chemotherapy. All recurrent patients received ketoconazole; four later underwent bilateral adrenalectomy. Six recurrent patients died 22-90 months (median, 57) after thymectomy. At last review, six patients were alive 14-90 months (median, 49) after thymectomy. These data are similar to those from the meta-analysis.

CONCLUSIONS

Thymic ACTH-producing NET is an aggressive disease that should be considered in CS with ectopic ACTH secretion, particularly in younger patients.

Impaired transforming growth factor-β (TGF-β) transcriptional activity and cell proliferation control of a menin in-frame deletion mutant associated with multiple endocrine neoplasia type 1 (MEN1)

Multiple endocrine neoplasia type 1 (MEN1) is characterized by tumors of the parathyroid, enteropancreas, and anterior pituitary. The MEN1 gene encodes the tumor suppressor menin of 610 amino acids that has multiple protein partners and activities. The particular pathways that, when lost, lead to tumorigenesis are not known. We demonstrated that members of a three-generation MEN1 kindred are heterozygous for a donor splice site mutation at the beginning of intron 3 (IVS3 + 1G→A). Lymphoblastoid cells of a mutant gene carrier had, in addition to the wild-type menin transcript, an aberrant transcript resulting from use of a cryptic splice site within exon III that splices to the start of exon IV. The predicted menin Δ(184-218) mutant has an in-frame deletion of 35 amino acids but is otherwise of wild-type sequence. The transfected menin Δ(184-218) mutant was well expressed and fully able to mediate the normal inhibition of the activity of the transcriptional regulators JunD and NF-κB. However, it was defective in mediating TGF-β-stimulated Smad3 action in promoter-reporter assays in insulinoma cells. Importantly, lymphoblastoid cells from an individual heterozygous for the mutation had reduced TGF-β-induced (Smad3) transcriptional activity but normal JunD and NF-κB function. In addition, the mutant gene carrier lymphoblastoid cells proliferated faster and were less responsive to the cytostatic effects of TGF-β than cells from an unaffected family member. In conclusion, the menin mutant exhibits selective loss of the TGF-β signaling pathway and loss of cell proliferation control contributing to the development of MEN1.

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.

Simultaneous double thymic carcinoids: a rare initial manifestation of multiple endocrine neoplasia type 1

A 53-year-old man was referred to our hospital for treatment of two anterior mediastinal tumors. The anterior mediastinal tumors were resected by thymectomy under the probable diagnosis of double thymomas. The final pathological diagnosis was multiple thymic carcinoids. Although 20%-25% of patients with thymic carcinoid have a family history of multiple endocrine neoplasia type 1 (MEN-1), radiographic screening just after the operation did not detect any endocrine tumors. However, the patient had a urinary calculus 4 months 7 months after the operation. Endocrinological examination then revealed mild hypercalcemia, hypophosphatemia, hyperinsulinemia, and hyperprolactinemia. Radiologically, a parathyroid tumor and a pancreatic tumor were found. The patient was referred to a university hospital and a mutation of MEN-1 gene was detected. The diagnosis of MEN-1 was confirmed about 1 year after the operation.

Ectopic ACTH syndrome associated with large cell neuroendocrine carcinoma of the thymus

A 38-year-old man was admitted for evaluation of Cushing's syndrome. Physical findings showed swelling of the face, and hypertension, but not Cushingoid stigmata. Laboratory data revealed serum cortisol level of 34.1 µg/dL and plasma ACTH of 140 pg/mL. Overnight administration of 1 and 8 mg dexamethasone did not suppress plasma ACTH or serum cortisol. Chest X-ray showed a mass at the upper-anterior quadrant of the mediastinum, and chest CT scan revealed a heterogenous tumor of approximately 60 mm in diameter, which infiltrated into the superior vena cava and ascending aorta, and caused superior vena cava syndrome. The tumor was resected. Histological examination indicated large cell neuroendocrine carcinoma of the thymus and positive immunoreactivity for ACTH. Ten days after the operation, the plasma ACTH decreased as low as 13.7 pg/mL. The present study indicates that large cell neuroendocrine carcinoma of the thymus can cause superior vena cava syndrome and ectopic ACTH syndrome.

Melanocytic bronchopulmonary carcinoid tumor in a patient with multiple endocrine neoplasia syndrome type 1: a case report with emphasis on intraoperative cytological findings

We present the cytological features along with histologic and imaging findings of a melanocytic bronchopulmonary carcinoid tumor in a patient with multiple endocrine neoplasia syndrome type 1 (MEN-1). Intraoperative touch preparations of the lung tumor showed single spindle cells and loosely cohesive aggregates of spindle cells with oval to elongated nuclei, "salt and pepper" chromatin pattern and inconspicuous nucleoli. The spindle cells occasionally contained cytoplasmic pigment, which revealed to be melanin by Fontana Masson stain on permanent processed material. Immunohistochemical stains for both synaptophysin and chromogranin were strongly positive in the spindle cells. The findings were consistent with melanocytic bronchopulmonary carcinoid tumor, which is relatively uncommon in MEN-1.