Well-differentiated pancreatic neuroendocrine carcinoma in tuberous sclerosis--case report and review of the literature. Am J Surg Pathol. 2012;36:149-153. [PMID: 22173120 DOI: 10.1097/pas.0b013e31823d0560]

Hereditary Syndromes Associated with Pancreatic and Lung Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PanNETs) and lung NETs (LNETs) represent a rare but clinically significant subgroup of neoplasms. While the majority is sporadic, approximately 17% of PanNETs and a subset of LNETs develop in the context of monogenic familial tumor syndromes, especially multiple endocrine neoplasia type 1 (MEN1) syndrome. Other inherited syndromes associated with PanNETs include MEN4, von Hippel-Lindau (VHL) syndrome, neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC). These syndromes are highly penetrant and their clinical manifestations may vary even among members of the same family. They are attributed to genetic mutations involving key molecular pathways regulating cell growth, differentiation, and angiogenesis. Pancreatic NETs in hereditary syndromes are often multiple, develop at a younger age compared to sporadic tumors, and are associated with endocrine and nonendocrine tumors derived from multiple organs. Lung NETs are not as common as PanNETs and are mostly encountered in MEN1 syndrome and include typical and atypical lung carcinoids. Early detection of PanNETs and LNETs related to inherited syndromes is crucial, and specific follow-up protocols need to be employed to optimize diagnosis and management. Genetic screening is recommended in childhood, and diagnostic screening starts often in adolescence, even in asymptomatic mutation carriers. Optimal management and therapeutic decisions should be made in the context of a multidisciplinary team in specialized centers, whereas specific biomarkers aiming to identify patients denoted to follow a more aggressive course need to be developed.

Malignant tumors in tuberous sclerosis complex: a case report and review of the literature

BACKGROUND

Tuberous sclerosis complex (TSC) is a rare, autosomal dominant genetic disease that arises from TSC1 or TSC2 genetic mutations. These genetic mutations can induce the development of benign tumors in any organ system with significant clinical implications in morbidity and mortality. In rare instances, patients with TSC can have malignant tumors, including renal cell carcinoma (RCC) and pancreatic neuroendocrine tumor (PNET). It is considered a hereditary renal cancer syndrome despite the low incidence of RCC in TSC patients. TSC is typically diagnosed in prenatal and pediatric patients and frequently associated with neurocognitive disorders and seizures, which are often experienced early in life. However, penetrance and expressivity of TSC mutations are highly variable. Herein, we present a case report, with associated literature, to highlight that there exist undiagnosed adult patients with less penetrant features, whose clinical presentation may contain non-classical signs and symptoms, who have pathogenic TSC mutations.

CASE PRESENTATION

A 31-year-old female with past medical history of leiomyomas status post myomectomy presented to the emergency department for a hemorrhagic adnexal cyst. Imaging incidentally identified a renal mass suspicious for RCC. Out of concern for hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome, the mass was surgically removed and confirmed as RCC. Discussion with medical genetics ascertained a family history of kidney cancer and nephrectomy procedures and a patient history of ungual fibromas on the toes. Genetic testing for hereditary kidney cancer revealed a 5'UTR deletion in the TSC1 gene, leading to a diagnosis of TSC. Following the diagnosis, dermatology found benign skin findings consistent with TSC. About six months after the incidental finding of RCC, a PNET in the pancreatic body/tail was incidentally found on chest CT imaging, which was removed and determined to be a well-differentiated PNET. Later, a brain MRI revealed two small cortical tubers, one in each frontal lobe, that were asymptomatic; the patient's history and family history did not contain seizures or learning delays. The patient presently shows no evidence of recurrence or metastatic disease, and no additional malignant tumors have been identified.

CONCLUSIONS

To our knowledge, this is the first report in the literature of a TSC patient without a history of neurocognitive disorders with RCC and PNET, both independently rare occurrences in TSC. The patient had a strong family history of renal disease, including RCC, and had several other clinical manifestations of TSC, including skin and brain findings. The incidental finding and surgical removal of RCC prompted the genetic evaluation and diagnosis of TSC, leading to a comparably late diagnosis for this patient. Reporting the broad spectrum of disease for TSC, including more malignant phenotypes such as the one seen in our patient, can help healthcare providers better identify patients who need genetic evaluation and additional medical care.

Long-Term Outcomes of Tuberous Sclerosis Complex-Associated Non-functional Pancreatic Neuroendocrine Tumors: Should We Be More Conservative?

BACKGROUND

Hereditary syndromes such as tuberous sclerosis complex (TSC) account for 10% of pancreatic neuroendocrine tumors (PNETs). Surgical intervention is the current standard of care for sporadic PNETs (spPNETs) that are >2 cm in size. We compared the long-term outcomes of resected TSC-PNETs with patients with spPNETs.

METHODS

We conducted a retrospective review of perioperative data and outcomes of TSC-PNETs compared with spPNETs. Inclusion criteria involved selecting patients whose tumors were no larger than 5.1 cm, the maximum size observed in the TSC-PNET group.

RESULTS

Of the 347 patients resected for PNETs, 14 were TSC-PNETs and 241 were non-functional spPNETs. The median age for the whole cohort was 56 years (interquartile range [IQR] 21.0) and 47% were female. The median follow-up was 103.8 months (95% confidence interval [CI] 89.2-118.6). Specifically, 14 patients with TSC-PNETs and 194 patients with spPNETs were included. Compared with spPNETs, patients with TSC-PNETs were operated on at a younger age (24.0 vs. 57.5 years; p < 0.001), were more frequently multifocal (28.5% vs. 0.0%; p < 0.001), were more likely to undergo minimally invasive operations (78.6% vs. 24.3%; p < 0.001), and had more R1 resections (28.6% vs. 5.7%; p = 0.006). Local and distant tumor recurrence was only observed in the spPNET group. The 5-year mortality rates for the spPNET and TSC-PNET groups were 6.2% and 0.0%, respectively. No PNET-related deaths were observed among TSC-PNETs.

CONCLUSION

None of the TSC-PNET patients recurred after a median follow-up of 78.0 months. The risk-benefit of aggressive pancreatic operations in TSC-PNET patients is still unclear and our findings suggest a conservative approach should be considered.

Tuberous sclerosis complex mutations in patients with pancreatic neuroendocrine tumors. Observations on phenotypic and treatment-related associations

Pancreatic neuroendocrine tumors (PanNETs) in familial tuberous sclerosis (TSC1 and TSC2 mutations) have been known and studied. However, little is known about PanNET patients harboring the very rare (less than 2%) sporadic TSC mutations. Some renal tumors have been shown to harbor sporadic TSC mutations, with a distinctive morphological correlate. We hereby describe this rather unusual molecular alteration in well-differentiated pancreatic neuroendocrine tumors (WD PanNETs) with a focus on their morphology and treatment outcomes. Six cases of WD PanNETs harboring sporadic TSC mutations were identified retrospectively. H&E slides and corresponding immunostains were reviewed for all cases. Clinical, molecular, and radiological information was obtained using the electronic medical records. Cohort consisted of 4 males and 2 females. Median age at diagnosis was 50 years (range 33-74 years). Origin of neoplasm was the pancreas and, in all but one, patient had liver metastasis by the time of presentation. Six out of six cases demonstrated a unique tumor morphology, with ample eosinophilic cytoplasm. Tumors were arranged in sheets and nests; prominent cystic change was noted in one case. Two cases were additionally biopsied post-treatment with capecitabine and temozolomide, and showed even more abundant oncocytic cytoplasm, eccentric nuclei, and a prominent cherry red nucleolus, and were arranged in a cluster of 3-4 cells, separated by stromal cells. Every patient had a different TSC2 variant with no cases of TSC1 mutations. Other common variants included MEN1 (4/6), DAXX (2/6), and TP53 (2/6). Per the WH0 2019 classification, tumors were graded as NET-G3 (n = 3) and NET-G2 (n = 3). Ki-67 s ranged from 7.2 to 60. All cases had retained MMR protein expression. The majority of patients (4/6) have expired. Although they received multiple treatments, a consistent pattern observed in patients was marked radiologic response to chemotherapy with capecitabine and temozolomide (offered in 5/6 patients) with duration of responses reaching 11 months in the majority of cases, with one patient showing near complete pathologic response of localized disease. TSC2 mutations may confer distinctive appearance in WD PanNETs, reminiscent of their effects in renal tumors. Although not entirely specific, this distinct morphological pattern with abundant eosinophilic cytoplasm in WD PanNETs could be reflective of an associated TSC mutation, with suggestions of significant therapeutic response to a specific cytotoxic chemotherapy.

Neuroendocrine neoplasms in the context of inherited tumor syndromes: a reappraisal focused on targeted therapies

PURPOSE

Neuroendocrine neoplasms can occur as part of inherited disorders, usually in the form of well-differentiated, slow-growing tumors (NET). The main predisposing syndromes include: multiple endocrine neoplasias type 1 (MEN1), associated with a large spectrum of gastroenteropancreatic and thoracic NETs, and type 4 (MEN4), associated with a wide tumour spectrum similar to that of MEN1; von Hippel-Lindau syndrome (VHL), tuberous sclerosis (TSC), and neurofibromatosis 1 (NF-1), associated with pancreatic NETs. In the present review, we propose a reappraisal of the genetic basis and clinical features of gastroenteropancreatic and thoracic NETs in the setting of inherited syndromes with a special focus on molecularly targeted therapies for these lesions.

METHODS

Literature search was systematically performed through online databases, including MEDLINE (via PubMed), and Scopus using multiple keywords' combinations up to June 2022.

RESULTS

Somatostatin analogues (SSAs) remain the mainstay of systemic treatment for NETs, and radiolabelled SSAs can be used for peptide-receptor radionuclide therapy for somatostatin receptor (SSTR)-positive NETs. Apart of these SSTR-targeted therapies, other targeted agents have been approved for NETs: the mTOR inhibitor everolimus for lung, gastroenteropatic and unknown origin NET, and sunitinib, an antiangiogenic tyrosine kinase inhibitor, for pancreatic NET. Novel targeted therapies with other antiangiogenic agents and immunotherapies have been also under evaluation.

CONCLUSIONS

Major advances in the understanding of genetic and epigenetic mechanisms of NET development in the context of inherited endocrine disorders have led to the recognition of molecular targetable alterations, providing a rationale for the implementation of treatments and development of novel targeted therapies.

Tuberous sclerosis complex-associated nonfunctional pancreatic neuroendocrine tumors: Management and surgical outcomes

We aimed to further characterize pancreatic involvement in tuberous sclerosis complex (TSC), with a focus on management of TSC-associated nonfunctional pancreatic neuroendocrine tumors (PNETs). This was a retrospective chart review of a large cohort of TSC patients. A total of 637 patients with a confirmed diagnosis of TSC were seen at the Herscot Center for Tuberous Sclerosis Complex at Massachusetts General Hospital. Of the 637 total patients with a confirmed diagnosis of TSC, 28 patients were found to have varying pancreatic findings ranging from simple-appearing cysts to well-differentiated PNETs. Thirteen of the 28 patients had PNET confirmed on pathology; 10 of these tumors were resected at Massachusetts General Hospital. None of the patients had serious perioperative or postoperative complications; only one of the patients had a recurrence following resection. As roughly 4.4% of our TSC patient population had pancreatic involvement, surveillance abdominal imaging should include evaluation of the pancreas instead of limiting to a renal protocol. Additionally, given the low risk of complications and recurrence combined with documented risk of metastasis in TSC-associated PNET, TSC patients with pancreatic lesions suspicious for PNETs should be considered as surgical candidates.

Epigenetic Regulation in Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine neoplasms are a rare, diverse group of neuroendocrine tumors that form in the pancreatic and gastrointestinal tract, and often present with side effects due to hormone hypersecretion. The pathogenesis of these tumors is known to be linked to several genetic disorders, but sporadic tumors occur due to dysregulation of additional genes that regulate proliferation and metastasis, but also the epigenome. Epigenetic regulation in these tumors includes DNA methylation, chromatin remodeling and regulation by noncoding RNAs. Several large studies demonstrate the identification of epigenetic signatures that may serve as biomarkers, and others identify innovative, epigenetics-based targets that utilize both pharmacological and theranostic approaches towards the development of new treatment approaches.

Neuroendocrine pancreatic tumor in a patient with dual diagnosis of tuberous sclerosis complex and basement membrane disease: A case report and review of the literature

Tuberous Sclerosis is a complex genetic disease that has well-defined clinical criteria. These criteria don't include pancreatic neuroendocrine tumors. We represent a rare case of a patient, with a non-functioning pancreatic neuroendocrine tumor and concomitant diagnosis of tuberous sclerosis complex, and basement membrane disease. The patient was diagnosed based on typical radiologic findings. We have suggested close monitoring and during follow-up studies, the disease was stable. Interestingly the patient tested negative for Tuberous Sclerosis Complex (TSC), which suggests that she might be a somatic mosaic and the mutation level in blood lymphocytes was below the detection level. Moreover, a heterozygous pathogenic variant p.(Gly774Arg) and a heterozygous likely pathogenic variant p.(Gly1465Asp) were identified in the COL4A4 gene. COL4A4 gene is responsible for causing autosomal dominant basement membrane disease. In this case report, we discuss clinical, radiologic, and genetic aspects of these diseases, as well as optimal treatment and follow-up strategies. Thus, by presenting this case we would like to increase awareness of pancreatic neuroendocrine tumors in TSC and emphasize the need for follow-up monitoring.

Hereditary Endocrine Tumors and Associated Syndromes: A Narrative Review for Endocrinologists and Endocrine Surgeons

OBJECTIVE

Hereditary endocrine tumors (HET) were among the first group of tumors where predisposition syndromes were recognized. The utility of genetic awareness is having the capacity to treat at an earlier stage, screen for other manifestations and initiate family cascade testing. The aim of this narrative review is to describe the most common hereditary syndromes associated with frequently encountered endocrine tumors, with an emphasis on screening and surveillance.

METHODS

A MEDLINE search of articles for relevance to endocrine tumors and hereditary syndromes was performed.

RESULTS

The most common hereditary syndromes associated with frequently encountered endocrine tumors are described in terms of prevalence, genotype, phenotype, penetrance of malignancy, surgical management, screening and surveillance.

CONCLUSION

Medical practitioners involved in the care of patients with endocrine tumors, should have an index of suspicion for an underlying hereditary syndrome. Interdisciplinary care is integral to successful, long-term management of these patients and affected family members.

A Direct Comparison of Patients With Hereditary and Sporadic Pancreatic Neuroendocrine Tumors: Evaluation of Clinical Course, Prognostic Factors and Genotype-Phenotype Correlations

Introduction

Pancreatic neuroendocrine tumors (PNETs) in hereditary syndromes pose a significant challenge to clinicians. The rarity of these syndromes and PNETs itself make it difficult to directly compare them with sporadic PNETs. Despite research suggesting differences between these two entities, the same approach is used in hereditary and sporadic PNETs.

Methods

We included 63 patients with hereditary PNET (GpNET) and 145 with sporadic PNET (SpNET) in a retrospective observational study. Clinical and genetic data were collected in two Polish endocrine departments from January 2004 to February 2020. Only patients with confirmed germline mutations were included in the GpNET cohort. We attempted to establish prognostic factors of metastases and overall survival in both groups and genotype-phenotype correlations in the GpNET group.

Results

Patients with GpNET were younger and diagnosed earlier, whereas their tumors were smaller and more frequently multifocal compared with patients with SpNET. Metastases occurred more frequently in the SpNET group, and their appearance was associated with tumor size in both groups. GpNET patients had longer overall survival (OS). OS was affected by age, age at diagnosis, sex, grade, stage, tumor diameter, occurrence and localization of metastases, type of treatment, and comorbidities. In the MEN1 group, carriers of frameshift with STOP codon, splice site, and missense mutations tended to have less advanced disease, while patients with mutations in exon 2 tended to have metastases more frequently.

Conclusions

Direct comparisons of GpNET and SpNET demonstrate significant differences in the clinical courses of both entities, which should force different approaches. A larger group of patients with GpNET should be assessed to confirm genotype-phenotype correlations.

Frequency, Progression, and Current Management: Report of 16 New Cases of Nonfunctional Pancreatic Neuroendocrine Tumors in Tuberous Sclerosis Complex and Comparison With Previous Reports

Background: Tuberous sclerosis complex (TSC) is a genetic condition that causes benign tumors to grow in multiple organ systems. Nonfunctional pancreatic neuroendocrine tumors (PNETs) are a rare clinical feature of TSC with no specific guidelines outlined for clinical management at this time. Our purpose is to calculate the frequency of nonfunctional PNETs as well as characterize the presentation, current clinical management, and assess the impact of systemic mammalian target of rapamycin (mTOR) on nonfunctional PNETs in TSC.

Methods: This retrospective chart review was performed by a query of the TS Alliance's Natural History Database and the Cincinnati Children's Hospital TSC Database for patients with nonfunctional PNET. Clinical data from these two groups was summarized for patients identified to have a nonfunctional PNET and compared to previously reported cases with TSC and nonfunctional PNETs.

Results: Our calculated frequency of nonfunctional PNETs is 0.65%. We identified 16 individuals, nine males and seven females, with a median age of 18.0 years (interquartile range: −15.5 to 25.5). Just over half (56.3%, n = 9) of the patients provided results from genetic testing. Six had pathogenic variants in TSC2 whereas three had pathogenic variants in TSC1. The average age at PNET diagnosis was 15.0 years (range: 3–46 years). Almost all individuals were diagnosed with a PNET during routine TSC surveillance, 56.3% (n = 9) by MRI, 12.5% (n = 2) by CT, 25% (n = 4) by ultrasound, and 6.2% (n = 1) through a surgical procedure. Follow up after diagnosis involved 68.8% (n = 11) having serial imaging and nine of the sixteen individuals proceeding with surgical removal of the PNET. Eight individuals had a history of using systemic mTOR inhibitors. Tumor growth rate was slightly less in individuals taking an mTOR inhibitor (−0.8 mm/yr, IQR: −2.3 to 2.2) than those without (1.6 mm/yr; IQR: −0.99 to 5.01, p > 0.05).

Conclusions: Nonfunctional PNETs occurred at younger ages in our TSC cohort and more commonly compared to ages and prevalence reported for the general population. PNETs in patients on systemic mTOR inhibitors had lower rates of growth. The outcome of this study provides preliminary evidence supporting the use of mTOR inhibitor therapy in conjunction with serial imaging as medical management for nonfunctional PNETs as an alternative option to invasive surgical removal.

Tuberous sclerosis patient with neuroendocrine carcinoma of the esophagogastric junction: A case report

BACKGROUND

Tuberous sclerosis complex (TSC) is a rare inherited disease with non-cancerous tumor growths in the skin, brain, kidneys, heart, and lungs. The co-occurrence of neuroendocrine neoplasm (NEN) with TSC is even rarer. There have been few reports on the relationship between TSC and neuroendocrine tumors (NETs), and fewer on the relationship between TSC and neuroendocrine carcinoma (NEC), a subtype of NEN. This is the first reported case of NEC occurring at the esophagogastric junction in a patient with TSC.

CASE SUMMARY

A 46-year-old woman visiting our hospital for the treatment of TSC was admitted to the emergency department with tarry stools and dizziness. Computed tomography scans revealed thickness of the gastric cardia, multiple metastatic lesions of the liver, and enlarged lymph nodes near the lesser curvature of the stomach. Esophagogastroduodenoscopy revealed a type 3 tumor located from the esophagogastric junction to the fundus, and the pathological diagnosis by biopsy was NEC. The patient was treated with seven courses of cisplatin + irinotecan, followed by eight courses of ramucirumab + nab-paclitaxel, one course of nivolumab, and two courses of S-1 + oxaliplatin. Twenty-three months after the first treatment, the patient died because of disease progression and deterioration of the general condition.

CONCLUSION

This case of NEC occurring in a patient with TSC indicates a difference in the occurrence of NETs and NECs.

[Inherited tumor syndromes of gastroenteropancreatic and thoracic neuroendocrine neoplasms]

About 5% of gastroenteropancreatic and thoracic neuroendocrine neoplasms (NENs) arise in the context of an inherited tumour syndrome. The two most frequent syndromes are: multiple endocrine neoplasia type 1 (MEN1), associated with a large spectrum of endocrine and non endocrine tumours, including duodenopancreatic, thymic and bronchial NENs, and the von Hippel-Lindau syndrome VHL, associated with pancreatic NENs. Two inherited syndromes have a low incidence of NENs: neurofibromatosis type 1 (NF1), associated with duodenal somatostatinomas, and tuberous sclerosis (TSC), associated with pancreatic NENs. Two rare syndromes have a high incidence of NENs: multiple endocrine neoplasia type 4 (MEN4), with a tumour spectrum similar to that of MEN1, and glucagon cell hyperplasia neoplasia (GCHN), involving only the pancreas. It is likely that other syndromes remain to be characterized, especially in familial small-intestinal NENs. The diagnosis is usually raised because of the suggestive clinical setting: young age at diagnosis, multiple tumours in multiple organs, familial history. Except in VHL and NF1, tumours themselves do not show specific pathological features; they usually are well differentiated and of low histological grade; their prognosis is good, except for MEN1-associated thymic NENs. The most suggestive pathological feature is their combination with various endocrine and/or non endocrine lesions in the adjacent tissue. Pathological examination is important, for a correct diagnosis and for an accurate management of the patients and their families, who must be referred to expert centers.

The North American Neuroendocrine Tumor Society Consensus Paper on the Surgical Management of Pancreatic Neuroendocrine Tumors

This manuscript is the result of the North American Neuroendocrine Tumor Society consensus conference on the surgical management of pancreatic neuroendocrine tumors from July 19 to 20, 2018. The group reviewed a series of questions of specific interest to surgeons taking care of patients with pancreatic neuroendocrine tumors, and for each, the available literature was reviewed. What follows are these reviews for each question followed by recommendations of the panel.

Pancreatic Neuroendocrine Tumor in a Young Child With Tuberous Sclerosis Complex 1

Pancreatic neuroendocrine tumors (PNETs) occur in the context of tuberous sclerosis complex (TSC). To date, PNETs in association with TSC have been described almost exclusively in adults and in the context of TSC2. We present the evaluation of a PNET in a young child with TSC1. A 3-year, 6-month-old boy with TSC1 was found on surveillance to have a small pancreatic lesion measuring 0.4 cm on magnetic resonance imaging (MRI). The lesion showed interval enlargement to 1 cm on serial MRI studies during the ensuing 16 weeks. Endocrine laboratory tests did not reveal a functional tumor. The patient underwent enucleation of the pancreatic lesion. Microscopic examination defined a well-differentiated PNET, grade II/intermediate grade with a mitotic rate of two mitotic figures per 10 high-powered field and Ki-67 proliferation index of ∼15%. The tumor was positive for the TSC1 gene mutation. The patient was free of tumor recurrence at the 5-year follow-up examination, as determined by endocrine surveillance and annual MRI of the abdomen. In the reported data, PNET in patients with TSC has been primarily reported in association with TSC2. Our case demonstrates that patients with TSC1 can develop PNETs, even at an early age. The international TSC consensus group 2012 recommendation was to obtain MRI of the abdomen every 1 to 3 years for surveillance of renal angiomyolipomas and renal cystic disease. It might be beneficial to add a pancreatic protocol to the surveillance guidelines to evaluate for PNET.

Genetics and Epigenetics of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are heterogeneous regarding site of origin, biological behavior, and malignant potential. There has been a rapid increase in data publication during the last 10 years, mainly driven by high-throughput studies on pancreatic and small intestinal neuroendocrine tumors (NETs). This review summarizes the present knowledge on genetic and epigenetic alterations. We integrated the available information from each compartment to give a pathway-based overview. This provided a summary of the critical alterations sustaining neoplastic cells. It also highlighted similarities and differences across anatomical locations and points that need further investigation. GEP-NENs include well-differentiated NETs and poorly differentiated neuroendocrine carcinomas (NECs). NENs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, NECs are G3 by definition. The distinction between NETs and NECs is also linked to their genetic background, as TP53 and RB1 inactivation in NECs set them apart from NETs. A large number of genetic and epigenetic alterations have been reported. Recurrent changes have been traced back to a reduced number of core pathways, including DNA damage repair, cell cycle regulation, and phosphatidylinositol 3-kinase/mammalian target of rapamycin signaling. In pancreatic tumors, chromatin remodeling/histone methylation and telomere alteration are also affected. However, also owing to the paucity of disease models, further research is necessary to fully integrate and functionalize data on deregulated pathways to recapitulate the large heterogeneity of behaviors displayed by these tumors. This is expected to impact diagnostics, prognostic stratification, and planning of personalized therapy.

Neoplasms of the Neuroendocrine Pancreas: An Update in the Classification, Definition, and Molecular Genetic Advances

This review focuses on discussing the main modifications of the recently published 2017 WHO Classification of Neoplasms of the Neuroendocrine Pancreas (panNEN). Recent updates separate pancreatic neuroendocrine tumors into 2 broad categories: well-differentiated pancreatic neuroendocrine tumors (panNET) and poorly differentiated pancreatic neuroendocrine carcinoma (panNEC), and incorporates a new subcategory of "well-differentiated high-grade NET (G3)" to the well-differentiated NET category. This new classification algorithm aims to improve the prediction of clinical outcomes and survival and help clinicians select better therapeutic strategies for patient care and management. In addition, these neuroendocrine neoplasms are capable of producing large quantity of hormones leading to clinical hormone hypersecretion syndromes. These functioning tumors include, insulinomas, glucagonomas, somatostatinomas, gastrinomas, VIPomas, serotonin-producing tumors, and ACTH-producing tumors. Although most panNENs arise as sporadic diseases, a subset of these heterogeneous tumors present as parts on inherited genetic syndromes, such as multiple endocrine neoplasia type 1, von Hippel-Lindau, neurofibromatosis type 1, tuberous sclerosis, and glucagon cell hyperplasia and neoplasia syndromes. Characteristic clinical and morphologic findings for certain functioning and syndromic panNENs should alert both pathologists and clinicians as appropriate patient management and possible genetic counseling may be necessary.

Thoracoabdominal imaging of tuberous sclerosis

Imaging of tuberous sclerosis complex has rapidly evolved over the last decade in association with increased understanding of the disease process and new treatment modalities. Tuberous sclerosis complex is best known for the neurological symptoms and the associated neuroimaging findings, and children with tuberous sclerosis complex require active surveillance of associated abnormalities in the chest, abdomen and pelvis. Common findings that require regular imaging surveillance are angiomyolipomas in the kidneys and lymphangioleiomyomatosis in the chest. However multiple rarer associations have been attributed to tuberous sclerosis complex and should be considered by radiologists reviewing any imaging in these children. In this review the authors discuss the spectrum of imaging findings in people with tuberous sclerosis complex, focusing on MR imaging findings in the chest, abdomen and pelvis.

Expanding the Spectrum of Colonic Manifestations in Tuberous Sclerosis: L-Cell Neuroendocrine Tumor Arising in the Background of Rectal PEComa

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous condition that predisposes to numerous proliferative lesions, including perivascular epithelioid cell tumors (PEComas), such as lymphangioleiomyomatosis (LAM) and angiomyolipomas, and rare neuroendocrine neoplasms. We describe herein a TSC2-harboring tuberous sclerosis patient manifesting with a synchronous well-differentiated L-cell rectal neuroendocrine tumor and leiomyomatosis-like LAM of the rectum. The background large bowel wall was thickened by confluent nodular areas comprising vessels and spindle-to-epithelioid cells, which are immunoreactive for myoid (smooth muscle actin, muscle specific actin, and desmin) and melanocytic markers (HMB45, Melan-A, microphthalmia transcription factor, and CD117). With the exception of TSC-related pancreatic neuroendocrine tumors, the association between tuberous sclerosis and neuroendocrine neoplasms remains largely unknown in the gastrointestinal tract. Neuroendocrine tumorigenesis in tuberous sclerosis is often linked to inactivating mutations of TSC2 leading to aberrant activation of mammalian target of rapamycin (mTOR) pathway. In this report, we document, for the first time, two foci of L-cell rectal neuroendocrine tumor arising in the setting of tuberous sclerosis, thus broadening the spectrum of TSC-associated endocrine disorders. Moreover, to our knowledge, this is only the second documented case of gastrointestinal leiomyomatosis-like LAM in a patient with tuberous sclerosis. The current case provides further evidence that, similar to pancreatic neuroendocrine tumors, neuroendocrine tumors of the luminal gastrointestinal tract may also be a feature of tuberous sclerosis and can be seen in association with PEComas.

Rapamycin ameliorates chitosan nanoparticle-induced developmental defects of preimplantation embryos in mice

Chitosan nanoparticles (CSNPs) are used as drug or gene delivery vehicles. However, a detailed understanding of the effects of CSNPs on embryonic development remains obscure. Here, we show that CSNPs can be internalized into mouse blastocysts, such as the zona pellucida, the perivitelline space, and the cytoplasm. Consequently, CSNPs-induced endoplasmic reticulum (ER) stress increases both of Bip/Grp78, Chop, Atf4, Perk, and Ire1a mRNAs expression levels, and reactive oxygen species. Moreover, CSNPs show double- and multi-membraned autophagic vesicles, and lead to cell death of blastocoels. Conversely, treatment with rapamycin, which plays an important role as a central regulator of cellular proliferation and stress responses, decreased CSNPs-induced mitochondrial Ca⁺² overloading, apoptosis, oxidative stress, ER stress, and autophagy. In vivo studies demonstrated that CSNPs injection has significant toxic effect on primordial and developing follicles. Notably, rapamycin rescued oxidative stress-induced embryonic defects via modulating gene expression of sirtuin and mammalian target of rapamycin. Interestingly, CSNPs treatment alters epigenetic reprogramming in mouse embryos. Overall, these observations suggest that rapamycin treatment could ameliorate CSNPs-induced developmental defects in preimplantation embryos. The data from this study would facilitate to understand the toxicity of these CSNPs, and enable the engineering of safer nanomaterials for therapeutic applications.

Hereditary Renal Cystic Disorders: Imaging of the Kidneys and Beyond

The purpose of this article is to review the hereditary renal cystic diseases that can manifest in children and adults, with specific attention to pathogenesis and imaging features. Various common and uncommon hereditary renal cystic diseases are reviewed in terms of their underlying etiology, including the involved genetic mutations and the affected proteins and cellular structures. Focus is placed on the morphologic findings in each condition and the features that distinguish one disorder from another. The two most common categories of hereditary renal cystic disease are (a) the ciliopathic disorders, which are related to mutations affecting the primary cilia (called "ciliopathies"), and (b) the phakomatoses. Autosomal dominant polycystic kidney disease, autosomal recessive polycystic kidney disease, and the "medullary cystic disease complex" are all ciliopathies but have different phenotypes. Tuberous sclerosis complex and the associated "contiguous gene syndrome," as well as von Hippel-Lindau syndrome, are phakomatoses that can manifest with cystic renal lesions but have uniquely different extrarenal manifestations. Finally, DICER1 mutations can manifest with renal cystic lesions (typically, cystic nephromas) in patients predisposed to other malignancies in the chest, ovaries, and thyroid. Although some overlap exists in the appearance of the renal cysts associated with each of these diseases, there are clear morphologic differences (eg, cyst size, location, and complexity) that are emphasized in this review. To improve patient outcomes, it is important for the radiologist to recognize the various hereditary renal cystic diseases so that a correct diagnosis is assigned and so that the patient is adequately evaluated and followed up. ^©RSNA, 2017.

Hereditary pancreatic cancer: related syndromes and clinical perspective

Pancreatic cancer is a very aggressive disease with a poor prognosis. The majority of them are attributed to sporadic causes, especially to many modifiable risk factors such as tobacco or alcohol abuse. The principal histologic subtype of pancreatic cancer is ductal adenocarcinoma. Pancreatic neuroendocrine tumors, which constitute a more indolent entity, represent second type of pancreatic cancer in terms of incidence. Individuals with a family history of pancreatic cancer carry an increased risk of developing the disease, which may be related to an underlying hereditary component. Unfortunately, in the majority of these families the suspected germline genetic cause responsible of the disease will not be identified, but approximately in a 20% of the cases a hereditary cancer predisposition syndrome with increased risk of pancreatic cancer development can be recognized. This review will be focused on the leading hereditary cancer syndromes related to pancreatic ductal adenocarcinoma and pancreatic neuroendocrine tumors. Additionally, we will try to explain clinical aspects related to the identification of germline mutations in pancreatic cancer patients and their potential implications in oncologic treatment decisions.

A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes

An understanding of the role of inherited cancer predisposition syndromes in pediatric tumor diagnoses continues to develop as more information is learned through the application of genomic technology. Identifying patients and their relatives at an increased risk for developing cancer is an important step in the care of this patient population. The purpose of this review is to highlight various tumor types that arise in the pediatric population and the cancer predisposition syndromes associated with those tumors. The review serves as a guide for recognizing genes and conditions to consider when a pediatric cancer referral presents to the genetics clinic.

Identification, genetic testing, and management of hereditary melanoma

Several distinct melanoma syndromes have been defined, and genetic tests are available for the associated causative genes. Guidelines for melanoma genetic testing have been published as an informal "rule of twos and threes," but these guidelines apply to CDKN2A testing and are not intended for the more recently described non-CDKN2A melanoma syndromes. In order to develop an approach for the full spectrum of hereditary melanoma patients, we have separated melanoma syndromes into two types: "melanoma dominant" and "melanoma subordinate." Syndromes in which melanoma is a predominant cancer type are considered melanoma dominant, although other cancers, such as mesothelioma or pancreatic cancers, may also be observed. These syndromes are associated with defects in CDKN2A, CDK4, BAP1, MITF, and POT1. Melanoma-subordinate syndromes have an increased but lower risk of melanoma than that of other cancer(s) seen in the syndrome, such as breast and ovarian cancer or Cowden syndrome. Many of these melanoma-subordinate syndromes are associated with well-established predisposition genes (e.g., BRCA1/2, PTEN). It is likely that these predisposition genes are responsible for the increased susceptibility to melanoma as well but with lower penetrance than that observed for the dominant cancer(s) in those syndromes. In this review, we describe our extension of the "rule of twos and threes" for melanoma genetic testing. This algorithm incorporates an understanding of the spectrum of cancers and genes seen in association with melanoma to create a more comprehensive and tailored approach to genetic testing.

Mammalian Target of Rapamycin Inhibitors and Life-Threatening Conditions in Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is a multisystem disease associated with an overall reduction in life expectancy due to the possible occurrence of different life-threatening conditions. Subjects affected by TSC are, in fact, at risk of hydrocephalus secondary to the growth of subependymal giant cell astrocytomas, or of sudden unexpected death in epilepsy. Other nonneurological life-threatening conditions include abdominal bleeding owing to renal angiomyolipomas rupture, renal insufficiency due to progressive parenchymal destruction by multiple cysts, pulmonary complications due to lymphangioleiomyomatosis, and cardiac failure or arrhythmias secondary to rhabdomyomas. In the last decades, there has been a great progress in understanding the pathophysiology of TSC-related manifestations, which are mainly linked to the hyperactivation of the so-called mammalian target of rapamycin (mTOR) pathway, as a consequence of the mutation in 1 of the 2 genes TSC1 or TSC2. This led to the development of new treatment strategies for this disease. In fact, it is now available as a biologically targeted therapy with everolimus, a selective mTOR inhibitor, which has been licensed in Europe and USA for the treatment of subependymal giant cell astrocytomas and angiomyolipomas in subjects with TSC. This drug also proved to benefit other TSC-related manifestations, including pulmonary lymphangioleiomyomatosis, cardiac rhabdomyomas, and presumably epileptic seizures. mTOR inhibitors are thus proving to be a systemic therapy able to simultaneously address different and potentially life-threatening complications, giving the hope of improving life expectation in individuals with TSC.

Pancreatic neuroendocrine tumor in a child with a tuberous sclerosis complex 2 (TSC2) mutation

OBJECTIVE

Pancreatic neuroendocrine tumors (PanNETs) are rare in children with tuberous sclerosis complex (TSC). The objective of this report is to describe a case of PanNET in a boy with TSC.

METHODS

We describe the patient's clinical presentation, biochemical workup, and laboratory tests.

RESULTS

A 10-year-old boy with a TSC2 mutation presented with a nonsecretory PanNET discovered during routine annual abdominal ultrasound. Surgical distal pancreatectomy with spleen preservation was undertaken. The excised tumor appeared nodular, whitish, and encapsulated. The tumor was composed of pancreatic endocrine monomorphic cells, and the solid appearance of the tumor was interrupted by areas of cystic degeneration. Mitoses were rare; the proliferation index was estimated around 4%. Local lymph nodes showed hyperplasia but were free of metastatic disease. Immunohistochemical examinations were positive for the neuroendocrine markers chromogranin, neurospecific enolase, synaptophysin, CAM52, and vimentin and were negative for CD10 and alpha-1 antitrypsin. The immunohistochemistry also showed a lack of hyperactivation of mammalian target of rapamycin (mTOR) mTOR pathway. All data supported the diagnosis of a grade II well-differentiated neuroendocrine neoplasm, according to the World Health Organization (WHO).

CONCLUSIONS

Thirteen non-secretory PanNET cases associated with TSC have been reported, including our patient (9 men and 4 women; 7 with TSC2 mutation). These tumors are usually asymptomatic and can be associated with metastasis; therefore, early diagnosis is crucial for prompt treatment. It is still unclear whether PanNETs should be considered a feature of TSC; however due to this association, we suggest that pancreas investigation should be included in routine examinations in men with TSC2 mutation.

Gastroenteropancreatic endocrine tumors

Gastroenteropancreatic endocrine tumors (GEP-NETs) are relatively uncommon; comprising approximately 0.5% of all human cancers. Although they often exhibit relatively indolent clinical courses, GEP-NETs have the potential for lethal progression. Due to their scarcity and various technical challenges, GEP-NETs have been understudied. As a consequence, we have few diagnostic, prognostic and predictive biomarkers for these tumors. Early detection and surgical removal is currently the only reliable curative treatment for GEP-NET patients; many of whom, unfortunately, present with advanced disease. Here, we review the genetics and epigenetics of GEP-NETs. The last few years have witnessed unprecedented technological advances in these fields, and their application to GEP-NETS has already led to important new information on the molecular abnormalities underlying them. As outlined here, we expect that "omics" studies will provide us with new diagnostic and prognostic biomarkers, inform the development of improved pre-clinical models, and identify novel therapeutic targets for GEP-NET patients.

Nonfunctional islet cell tumor of the pancreas in a patient with tuberous sclerosis: a case report with literature review

Islet cell tumors (ICTs) are rare tumors of the pancreas. Association of this type of tumor with tuberous sclerosis is extremely rare. Only 13 cases of pancreatic ICT with tuberous sclerosis have so far been documented in the literature. However, awareness of the association of tuberous sclerosis and ICT is important for early diagnosis and appropriate treatment of this condition. This article presents the case of a 63-year-old female with angiomyolipoma (AML) of the kidney and liver, calcified subependymal nodules and a large mass in the pancreas, which was proven to be an ICT on histopathological examination.

Current understanding of the molecular biology of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are complicated and often deadly neoplasms. A recent increased understanding of their molecular biology has contributed to expanded treatment options. DNA sequencing of samples derived from patients with PanNETs and rare genetic syndromes such as multiple endocrine neoplasia type 1 (MEN1) and Von Hippel-Lindau (VHL) syndrome reveals the involvement of MEN1, DAXX/ATRX, and the mammalian target of rapamycin (mTOR) pathways in PanNET tumorigenesis. Gene knock-out/knock-in studies indicate that inactivation of factors including MEN1 and abnormal PI3K/mTOR signaling uncouples endocrine cell cycle progression from the control of environmental cues such as glucose, leading to islet cell overgrowth. In addition, accumulating evidence suggests that further impairment of endothelial-endocrine cell interactions contributes to tumor invasion and metastasis. Recent phase III clinical trials have shown that therapeutic interventions, such as sunitinib and everolimus, targeting those signal transduction pathways improve disease-free survival rates. Yet, cure in the setting of advanced disease remains elusive. Further advances in our understanding of the molecular mechanisms of PanNETs and improved preclinical models will assist in developing personalized therapy utilizing novel drugs to provide prolonged control or even cure the disease.

A differential diagnosis of inherited endocrine tumors and their tumor counterparts

Inherited endocrine tumors have been increasingly recognized in clinical practice, although some difficulties still exist in differentiating these conditions from their sporadic endocrine tumor counterparts. Here, we list the 12 main topics that could add helpful information and clues for performing an early differential diagnosis to distinguish between these conditions. The early diagnosis of patients with inherited endocrine tumors may be performed either clinically or by mutation analysis in at-risk individuals. Early detection usually has a large impact in tumor management, allowing preventive clinical or surgical therapy in most cases. Advice for the clinical and surgical management of inherited endocrine tumors is also discussed. In addition, recent clinical and genetic advances for 17 different forms of inherited endocrine tumors are briefly reviewed.

The role of mechanistic target of rapamycin (mTOR) complexes signaling in the immune responses

The mechanistic Target of Rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase which is a member of the PI3K related kinase (PIKK) family. mTOR emerged as a central node in cellular metabolism, cell growth, and differentiation, as well as cancer metabolism. mTOR senses the nutrients, energy, insulin, growth factors, and environmental cues and transmits signals to downstream targets to effectuate the cellular and metabolic response. Recently, mTOR was also implicated in the regulation of both the innate and adaptive immune responses. This paper will summarize the current knowledge of mTOR, as related to the immune microenvironment and immune responses.

Unusual solid pancreatic tumors

The vast array of possible histologies for a given pancreatic mass makes the specific diagnosis of a solid pancreatic mass in an individual patient challenging. This article discusses and reviews the imaging findings of those entities that are likely to be encountered in clinical practice, specifically pancreatic endocrine tumors, solid pseudopapillary tumor, secondary pancreatic masses, and heterotopic spleen.