Pancreatic tumors in children and young adults with tuberous sclerosis complex

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.

The Spectrum of Familial Pituitary Neuroendocrine Tumors

Hereditary pituitary tumorigenesis is seen in a relatively small proportion (around 5%) of patients with pituitary neuroendocrine tumors (PitNETs). The aim of the current review is to describe the main clinical and molecular features of such pituitary tumors associated with hereditary or familial characteristics, many of which have now been genetically identified. The genetic patterns of inheritance are classified into isolated familial PitNETs and the syndromic tumors. In general, the established genetic causes of familial tumorigenesis tend to present at a younger age, often pursue a more aggressive course, and are more frequently associated with growth hormone hypersecretion compared to sporadic tumors. The mostly studied molecular pathways implicated are the protein kinase A and phosphatidyl-inositol pathways, which are in the main related to mutations in the syndromes of familial isolated pituitary adenoma (FIPA), Carney complex syndrome, and X-linked acrogigantism. Another well-documented mechanism consists of the regulation of p27 or p21 proteins, with further acceleration of the pituitary cell cycle through the check points G1/S and M/G1, mostly documented in multiple endocrine neoplasia type 4. In conclusion, PitNETs may occur in relation to well-established familial germline mutations which may determine the clinical phenotype and the response to treatment, and may require family screening.

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.

Genetics of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (pNETs) represent a relatively rare disease; however, the incidence has been increasing during the last 2 decades. Next generation sequencing has greatly increased our understanding of driver mutations in pNETs. Sporadic pNETs have consistently presented with mutations in MEN1, DAXX/ATRX, and genes related to the mammalian target of rapamycin pathway. Inherited pNETs have traditionally been associated with multiple endocrine neoplasia type 1, von Hippel-Lindau syndrome, neurofibromatosis type 1, and tuberous sclerosis complex. The current review expands on the existing knowledge and the relevant updates on the genetics of pNETs.

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.

Pancreatic Neuroendocrine Neoplasms: Updates on Genomic Changes in Inherited Tumour Syndromes and Sporadic Tumours Based on WHO Classification

Pancreatic neuroendocrine neoplasms (PanNENs) are the neuroendocrine neoplasms with greatest rate of increase in incidence. Approximately 10% of PanNENs arise as inherited tumour syndromes which include multiple endocrine neoplasia type 1, multiple endocrine neoplasia type 4, von Hippel-Lindau syndrome, neurofibromatosis type1, tuberous sclerosis complex 1/2, Cowden syndrome, and Glucagon cell hyperplasia and neoplasia as well as familial insulinomatosis. In sporadic PanNENs, driver mutations in MEN1, DAXX/ATRX and mTOR pathway genes are associated with development and progression in pancreatic neuroendocrine tumours. The other changes are in VEGF pathway, Notch pathway, germline mutations in MUTYH, CHEK2, BRCA2, PHLDA3 as well as other genetic alterations. On the other hand, pancreatic neuroendocrine carcinomas share similar genetic alterations with ductal adenocarcinomas, e.g., TP53, RB1 or KRAS. In addition, microRNA and changes in immune microenvironment were noted in PanNENs. Updates on these genetic knowledges contribute to the development of management strategies for patients with PanNENs.

Aortic Thrombus Embolization in A Patient with Tuberous Sclerosis

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder affecting many organ systems. Patients commonly develop a variety of benign tumors as well as neurological disease, including seizures, autism, and cognitive delay. We report here the case of an adolescent patient with TSC and a history of mild COVID-19 who presented with a 1-day history of altered mental status. The patient was found to have ischemic cerebral infarction of the right MCA and ACA territories. Initial angiography showed an occlusion of the right internal carotid artery without a demonstrable etiology, with follow-up echocardiography and angiography revealing a large aortic thrombus. The patient was not a candidate for thrombus removal due to her cerebral infarct and received medical anticoagulation. Thrombosis progressed to involve the left ICA, with left cerebral infarction and subsequent death. Aortic thrombus embolization as a cause of cerebrovascular accident (CVA) is a novel finding in the setting of TSC and should be considered for pediatric patients with CVA of unknown etiology. It is unclear whether this was related to the prior COVID-19 infection.

Pancreatic Neuroendocrine Neoplasms: Landscape and Horizon

CONTEXT.—

Since the initial description of pancreatic endocrine physiology and the recognition of islet cell tumors in the 1800s, there have been noteworthy advances in the pathobiology of pancreatic neuroendocrine neoplasms (PanNENs), and definition of the important distinction between well-differentiated neuroendocrine tumor (PanNET) and poorly differentiated neuroendocrine carcinoma (PanNEC). The evolving knowledge has resulted in a continuous update in terminology, classification, and grading system for this group of neoplasms. Pancreatic neuroendocrine tumors associated with hereditary conditions have been linked to unique molecular and genetic events, and sporadic PanNETs have specific gene signatures. Based on accumulative experience and knowledge, therapeutic strategies have been defined for this group of neoplasms.

OBJECTIVE.—

To review the evolution and description of the pathologic-genomic evolution of PanNENs, and to facilitate accurate pathologic interpretation for the corresponding clinical management.

DATA SOURCES.—

Literature review of published studies and author's own work.

CONCLUSIONS.—

Evolving experience and knowledge have established subtypes of pancreatic neuroendocrine neoplasms, based on their genotype and phenotype. Accurate pathologic interpretation of the specific neoplasm has significant implications for therapy and prognosis.

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 Complex with rare associated findings in the gastrointestinal system: a case report and review of the literature

Background

Tuberous Sclerosis Complex (TSC) is a complex and heterogeneous genetic disease that has well-established clinical diagnostic criteria. These criteria do not include gastrointestinal tumors.

Case presentation

We report a 45-year-old patient with a clinical and molecular diagnosis of TSC and a family history of cancer, presenting two rare associated findings: gastrointestinal polyposis and pancreatic neuroendocrine tumor. This patient was subjected to a genetic test with 80 cancer predisposing genes. The genetic panel revealed the presence of a large pathogenic deletion in the TSC2 gene, covering exons 2 to 16 and including the initiation codon. No changes were identified in the colorectal cancer and colorectal polyposis genes.

Discussion and conclusions

We describe a case of TSC that presented tumors of the gastro intestinal tract that are commonly unrelated to the disease. The patient described here emphasizes the importance of considering polyposis of the gastrointestinal tract and low grade neuroendocrine tumor as part of the TSC syndromic phenotype.

[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.

Interesting pancreatic tumour in the background of Tuberous Sclerosis

Tuberous Sclerosis Complex (TSC) is easily discernible by a myriad of manifestations, most notably dermatological. It is associated with well known and recognised intra-abdominal tumours like angiomyolipoma of the kidney. However, rarer tumours like pancreatic neuroendocrine tumours can occur in the setting of TSC. A high index of suspicion is necessary to identify and treat these lesions early in their natural course. Early identification augurs well with complete surgical excision and excellent survival.

Everolimus as adjunctive therapy for tuberous sclerosis complex-associated partial-onset seizures

Introduction: Tuberous sclerosis complex (TSC) is a rare genetic disorder resulting in benign tumors in various organs. It is caused by mutations in TSC1 or TSC2 genes causing hyperactivation of the mammalian target of rapamycin (mTOR) pathway. The majority of patients with TSC develop epilepsy, and approximately two-thirds become refractory to antiepileptic drugs (AEDs). Recently, the mTOR inhibitor everolimus was approved as adjunctive therapy for TSC-associated partial seizures. Areas covered: This article covers different characteristics of everolimus, including major clinical trials leading to its approval in TSC-associated partial seizures, safety concerns, drug pharmacokinetics/pharmacodynamics, and an overview of potential competitors and other agents used to treat TSC-associated seizures. Expert opinion: Unlike many other therapies for treating TSC-associated seizures, everolimus addresses the underlying pathophysiology of TSC, and since it has also been shown to improve other TSC manifestations such as subependymal giant cell astrocytomas and renal angiomyolipomas, everolimus provides a potential multisystemic therapy for TSC. An important avenue for future research is exploring the possible use of everolimus as a preventative treatment for seizures as there is the potential to prevent negative developmental outcomes associated with TSC.

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.

Overview of Genetically Determined Diseases/Multiple Endocrine Neoplasia Syndromes Predisposing to Endocrine Tumors

In this chapter, we present an overview of multiple endocrine neoplasia syndromes including their most important clinical and molecular features. Multiple endocrine neoplasia type 1 and 2 syndromes (MEN1 and MEN2) are discussed in detail. Syndromes that are presented in other chapters are only briefly mentioned. We discuss the relevance of germline gene alterations in apparently sporadic endocrine tumors, e.g., medullary thyroid cancer, primary hyperparathyroidism, and neuroendocrine tumors. McCune-Albright syndrome that only exists in non-hereditary, sporadic forms is also discussed in detail, as tumors of several endocrine organs can develop in the same individual.

Less common manifestations in TSC

Tuberous sclerosis complex (TSC) is due to pathogenic variants in TSC1 or TSC2 genes resulting in hyperactivation of the mTOR pathway. Many organ systems can be affected, such as brain, skin, eye, heart, bone, kidney, or lung. Typical lesions of TSC usually are those included as major criteria, including angiofibromas, hypomelanotic macules, tubers, subependymal nodules, angiomyolipomas, cardiac rhabdomyomas, and lymphangioleiomyomatosis. However, there are many other manifestations less frequent and/or less well known, many of them not included as clinical diagnostic criteria that are part of the clinical spectrum of TSC. The focus of this review will be on these less common and less well-known manifestations of TSC. Among the rare manifestations, we will discuss some clinical findings including arteriopathy, arachnoid cysts, lymphatic involvement, chordomas, gynecological, endocrine, and gastrointestinal findings. Among the manifestations that are very frequent but much less well known, we find the sclerotic bone lesions. Although they are very frequent in TSC they have been largely overlooked and not considered diagnostic criteria, mainly because they are asymptomatic. However, it is important to know their typical characteristics to avoid misdiagnosing them as metastasis.

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.

Imaging and Screening of Pancreatic Cancer

Given the low disease prevalence of both exocrine and endocrine cancers in the general population, screening is not recommended. However, in as many as 25% of cases there is a precursor lesion or an identifiable genetic predisposition. For these patients at increased risk, screening with imaging is recommended. Multidetector computed tomography, MR imaging or magnetic resonance cholangiopancreatography, and endoscopic ultrasound examination can be used as screening modalities. Recent advances in dual energy CT and total body MR imaging have increased the suitability of these noninvasive modalities as first-line imaging screening options.