Management of Abdominal Paraganglioma: A Single Center's Experience.

Background and Objectives: Paragangliomas (PGLs) are rare neuroendocrine extra-adrenal tumors that could be secreting mass. The symptoms are the typical triad of paroxysmal headache, hypertension and sweating, but could also be accompanied by symptoms involving multiple organs. Surgery is the gold standard treatment for both PGLs and pheochromocytomas (PHEOs). Material and Methods: We used a computerized endocrine surgery registry to record the demographic and clinical data of 153 patients who underwent surgery for PPGL between 2010 and 2023 at our hospital. Results: Thirteen patients (8.43%) with paragangliomas underwent surgery at our institute. Five patients presented symptomatic syndrome. Preoperative investigations included enhanced abdominal CT (nine patients) and enhanced MRI (seven patients). In cases of suspicious mass, we performed 131I-MIBG scans (two patients) or 68GA-DOTATOC PET-CT scans (11 patients). Laparoscopic approach was used in four cases (30.7%) and abdominal laparotomy in the other nine (69.3%). Biochemical tests were performed on all patients. Conclusions: In this retrospective study, we discuss the multidisciplinary management in our institute of this rare disease, from its challenging diagnosis to the surgical strategy for PGLs. Laparoscopic surgery is the gold standard, but a tailored approach should be adopted for each patient.

Improving Outcomes in Carotid Body Tumors Treatment: The Impact of a Multidisciplinary Team Approach.

BACKGROUND: The purpose of this study was to evaluate how a multidisciplinary approach, including patients and familiar genetic counseling, preoperative succinate-dehydrogenase (SDH) gene mutation analysis, preoperative adjunctive endovascular procedures (PAEPs) and postoperative rehabilitative team may affect the outcomes in patients who underwent surgery for carotid body tumors (CBTs). METHODS: Fifty-seven consecutive CBT resections were performed from January 1995 to December 2019 in a single center institution. Two groups of patients were compared: group A (1995-2003; n = 10) and group B (2004-2019; n = 47), treated before and after the establishment of a multidisciplinary approach to CBTs. Group A and group B were evaluated retrospectively and prospectively for SDH mutations, respectively. PAEPs (external carotid artery stenting, percutaneous transfemoral embolization or direct percutaneous puncture of the tumor with simultaneous embolization) were performed only in patients of group B, when the size of the tumor exceeded the 45 mm. Primary endpoints were blood loss (BL) and cranial nerve injuries. Secondary endpoint was the number of new silent masses (NSMs) discovered after genetic evaluation. RESULTS: SDH mutations were found in 2 patients of group A and in 11 patients of group B. There were no significant differences in mass diameter between the groups. A significant difference regarding the surgical procedure time was observed in the 2 groups, with a higher time in the group A (Group A: 180 ± 77.3; Group B: 138 ± 54.5, P= 0.04). BL was significantly lower in group B (203 ± 69.5 mL vs. 356 ± 102 mL; P = 0.0001), as well as for patients underwent PAEPs vs. those underwent direct surgery (n = 15, 149 ± 53 mL vs. n = 42, 273 ± 88 mL; P = 0.0001). No differences between transient and persistent cranial nerve injuries were observed between the 2 groups. Carotid reconstruction was necessary for 2 patients of group A (n = 2 vs. n = 0; P = 0.02). Unilateral tumor recurrence was detected in 7 patients, with a significantly higher rate (P ≤ 0.002) in patients carrying SDH mutations compared to those without SDH mutation (wild-type). SDH mutations detected in the groups lead to discover 7 NSMs (group A n = 1 vs. group B n = 6; P = 1.00). CONCLUSION: The impact of the multidisciplinary team suggests that surgical resection still remains the gold standard for the treatment of CBTs, but the use of PAEPs in selected cases may reduce surgical procedure time, BL and the need for reconstructive carotid surgery. Genetic counseling and SDH gene analysis allow to diagnose NSMs in asymptomatic patients. Larger studies should be considered to evaluate the effectiveness of postoperative rehabilitative program.

Pheochromocytomas and paragangliomas in children: Data from the Italian Cooperative Study (TREP).

BACKGROUND: Pheochromocytomas (PCs) are neuroendocrine tumors arising from the chromaffin cells of the adrenal gland, and paragangliomas (PGLs) are their extra-adrenal counterparts arising from ganglia along the sympathetic/parasympathetic chain. Surgery is the cornerstone of treatment. A sporatic or inherited germline mutation is commonly associated. MATERIALS AND METHODS: Among over 1000 patients registered into the Tumori Rari in Età Pediatrica-rare tumors in pediatric age project-from 2000 to 2019, 50 were affected by PC/PGL. All clinical and therapeutic data were evaluated. RESULTS: Twenty-eight patients had PC and 22 had PGL. Age at diagnosis ranged between 5 and 17 years. Thirty-five patients had symptoms related to catecholamine hypersecretion; in 7 of 50 patients, diagnosis was incidental or done during assessment of a familial syndrome. In all cases, conventional imaging was effective to assess the presence of a tumor. In addition, 18 of 38 functional imaging studies were positive (61%). Forty-eight patients were eligible for surgery: a complete resection was more frequently achieved in PC than in PGL (26/28 vs 11/22). All relapses were treated with surgery alone, surgery plus medical treatment, or chemotherapy alone; one PC with metastasis at diagnosis received radiotherapy only. Forty-four patients were in the first, second, or third complete remission (10/50 recurred; 8/10 carried a germline mutation). Five of 50 patients were alive with disease. One patient died of disease. CONCLUSIONS: Surgery can be curative in most tumors but it may not be always effective in removing PGLs. Severe postsurgical sequelae may affect these patients. Genetic tests should always be considered in individuals affected, and genetic counseling should be offered to their families.

E2F1 germline copy number variations and melanoma susceptibility.

BACKGROUND: Melanoma is an aggressive type of skin cancer whose aetiology remains elusive as both environmental and genetic factors can contribute to its development. Recent studies have demonstrated the existence of multiple copies of E2F1 gene in melanoma specimens which could explain the deregulated E2F1 activity in this type of cancer. This finding suggests a key role for this transcription factor in the malignant transformation of melanocytes. Therefore, E2F1 has been considered as a potential therapeutic target for this form of skin cancer. Since germline copy number variations (CNVs) have been associated with increased susceptibility to different types of cancer, the aim of our study was to assess germline E2F1 CNV in melanoma patients. However, CNVs not necessarily lead to gene dosage imbalance, hence, further factors, in association with CNVs, could contribute to clinical manifestations. Considering that heat stress has been hypothesised as a contributing factor to skin cancer, we also investigated the effect of heat stress on E2F1 expression. METHODS: E2F1 CNV was measured in genomic DNA isolated from blood of 552 patients diagnosed with melanoma and 520 healthy subjects using TaqMan Copy Number Assays. E2F1 mRNA expression was also evaluated by RT-qPCR in the melanoma cell line, SK MEL 267, before and after exposure to heat stress. RESULTS: We found that patients diagnosed with melanoma (1.6%, 9/552) harboured frequently altered germline E2F1 copies compared to healthy subjects (0%, 0/520). Moreover, the difference among the two groups was statistically significant (p = 0.004). Furthermore, we found that heat exposure alone can significantly induce E2F1 expression. CONCLUSIONS: This is the first study that shows a relation between germline E2F1 CNV and melanoma, suggesting that altered copies of this gene might be a predisposing factor to skin cancer. Our results also suggest that environmental insults, such as heat stress, could contribute to an aberrant E2F1 activity by inducing E2F1 mRNA expression. Therefore, subjects with multiple constitutive copies of E2F1 are at greater risk of developing melanoma when exposed to heat. Altogether our results corroborate with the hypothesis that susceptibility to melanoma depends on both the environment and genetic factors.

Gain-of-function mutations in DNMT3A in patients with paraganglioma.

PURPOSE: The high percentage of patients carrying germline mutations makes pheochromocytomas/paragangliomas the most heritable of all tumors. However, there are still cases unexplained by mutations in the known genes. We aimed to identify the genetic cause of disease in patients strongly suspected of having hereditary tumors. METHODS: Whole-exome sequencing was applied to the germlines of a parent-proband trio. Genome-wide methylome analysis, RNA-seq, CRISPR/Cas9 gene editing, and targeted sequencing were also performed. RESULTS: We identified a novel de novo germline mutation in DNMT3A, affecting a highly conserved residue located close to the aromatic cage that binds to trimethylated histone H3. DNMT3A-mutated tumors exhibited significant hypermethylation of homeobox-containing genes, suggesting an activating role of the mutation. CRISPR/Cas9-mediated knock-in in HeLa cells led to global changes in methylation, providing evidence of the DNMT3A-altered function. Targeted sequencing revealed subclonal somatic mutations in six additional paragangliomas. Finally, a second germline DNMT3A mutation, also causing global tumor DNA hypermethylation, was found in a patient with a family history of pheochromocytoma. CONCLUSION: Our findings suggest that DNMT3A may be a susceptibility gene for paragangliomas and, if confirmed in future studies, would represent the first example of gain-of-function mutations affecting a DNA methyltransferase gene involved in cancer predisposition.

Paragangliomas arise through an autonomous vasculo-angio-neurogenic program inhibited by imatinib.

Tumours can be viewed as aberrant tissues or organs sustained by tumorigenic stem-like cells that engage into dysregulated histo/organogenetic processes. Paragangliomas, prototypical organoid tumours constituted by dysmorphic variants of the vascular and neural tissues found in normal paraganglia, provide a model to test this hypothesis. To understand the origin of paragangliomas, we built a biobank comprising 77 cases, 18 primary cultures, 4 derived cell lines, 80 patient-derived xenografts and 11 cell-derived xenografts. We comparatively investigated these unique complementary materials using morphofunctional, ultrastructural and flow cytometric assays accompanied by microRNA studies. We found that paragangliomas contain stem-like cells with hybrid mesenchymal/vasculoneural phenotype, stabilized and expanded in the derived cultures. The viability and growth of such cultures depended on the downregulation of the miR-200 and miR-34 families, which allowed high PDGFRA and ZEB1 protein expression levels. Both tumour tissue- and cell culture-derived xenografts recapitulated the vasculoneural paraganglioma structure and arose from mesenchymal-like cells through a fixed developmental sequence. First, vasculoangiogenesis organized the microenvironment, building a perivascular niche which in turn supported neurogenesis. Neuroepithelial differentiation was associated with severe mitochondrial dysfunction, not present in cultured paraganglioma cells, but acquired in vivo during xenograft formation. Vasculogenesis was the Achilles' heel of xenograft development. In fact, imatinib, that targets endothelial-mural signalling, blocked paraganglioma xenograft formation (11 xenografts from 12 cell transplants in the control group versus 2 out of 10 in the treated group, P = 0.0015). Overall our key results were unaffected by the SDHx gene carrier status of the patient, characterized for 70 out of 77 cases. In conclusion, we explain the biphasic vasculoneural structure of paragangliomas and identify an early and pharmacologically actionable phase of paraganglioma organization.

Correction to: Paragangliomas arise through an autonomous vasculo-angio-neurogenic program inhibited by imatinib.

The given and family names of two co-authors were incorrect in the published article. The correct spelling should read as: Sampath Chandra Prasad and Vinagolu K Rajasekhar.

Temozolomide treatment of a malignant pheochromocytoma and an unresectable MAX-related paraganglioma.

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are neuroendocrine tumors with a strong genetic background. The mainstay of treatment for PCC/PGLs is surgery. However, for unresectable lesions, no curative treatment is currently available. Temozolomide (TMZ) has been shown to determine radiological and biochemical response in malignant PCC/PGLs. We report two cases of PCC/PGLs treated with TMZ. Case 1 is a 51-year-old man with local and distant recurrence (liver and bone metastases) of right adrenal PCC. Case 2 is a 54-year-old woman with a PCC/PGL syndrome caused by a mutation in MAX gene (c.171+1G>A), operated on for bilateral adrenal PCC and presenting with a large unresectable abdominal PGL. Both patients presented hypertension due to catecholamine hypersecretion. TMZ determined radiological response according to RECIST criteria, reduction of urinary catecholamine levels, and controlled hypertension in both patients. Furthermore, the current study demonstrates, for the first time, that MAX-related PGLs are responsive to TMZ.

A novel mutation in the upstream open reading frame of the CDKN1B gene causes a MEN4 phenotype.

The CDKN1B gene encodes the cyclin-dependent kinase inhibitor p27(KIP1), an atypical tumor suppressor playing a key role in cell cycle regulation, cell proliferation, and differentiation. Impaired p27(KIP1) expression and/or localization are often observed in tumor cells, further confirming its central role in regulating the cell cycle. Recently, germline mutations in CDKN1B have been associated with the inherited multiple endocrine neoplasia syndrome type 4, an autosomal dominant syndrome characterized by varying combinations of tumors affecting at least two endocrine organs. In this study we identified a 4-bp deletion in a highly conserved regulatory upstream ORF (uORF) in the 5'UTR of the CDKN1B gene in a patient with a pituitary adenoma and a well-differentiated pancreatic neoplasm. This deletion causes the shift of the uORF termination codon with the consequent lengthening of the uORF-encoded peptide and the drastic shortening of the intercistronic space. Our data on the immunohistochemical analysis of the patient's pancreatic lesion, functional studies based on dual-luciferase assays, site-directed mutagenesis, and on polysome profiling show a negative influence of this deletion on the translation reinitiation at the CDKN1B starting site, with a consequent reduction in p27(KIP1) expression. Our findings demonstrate that, in addition to the previously described mechanisms leading to reduced p27(KIP1) activity, such as degradation via the ubiquitin/proteasome pathway or non-covalent sequestration, p27(KIP1) activity can also be modulated by an uORF and mutations affecting uORF could change p27(KIP1) expression. This study adds the CDKN1B gene to the short list of genes for which mutations that either create, delete, or severely modify their regulatory uORFs have been associated with human diseases.

Thyroid cancer GWAS identifies 10q26.12 and 6q14.1 as novel susceptibility loci and reveals genetic heterogeneity among populations.

Thyroid cancer is the most heritable cancer of all those not displaying typical Mendelian inheritance. However, most of the genetic factors that would explain the high heritability remain unknown. Our aim was to identify additional common genetic variants associated with susceptibility to this disease. In order to do so, we performed a genome-wide association study in a series of 398 cases and 502 controls from Spain, followed by a replication in four well-defined Southern European case-control collections contributing a total of 1,422 cases and 1,908 controls. The association between the variation at the 9q22 locus near FOXE1 and thyroid cancer risk was consistent across all series, with several SNPs identified (rs7028661: OR = 1.64, p = 1.0 × 10(-22) , rs7037324: OR = 1.54, p = 1.2 × 10(-17) ). Moreover, the rare alleles of three SNPs (rs2997312, rs10788123 and rs1254167) at 10q26.12 showed suggestive evidence of association with higher risk of the disease (OR = 1.35, p = 1.2 × 10(-04) , OR = 1.26, p = 5.2 × 10(-04) and OR = 1.38, p = 5.9 × 10(-05) , respectively). Finally, the rare allele of rs4075570 at 6q14.1 conferred protection in the series studied (OR = 0.82, p = 2.0 × 10(-04) ). This study suggests that heterogeneity in genetic susceptibility between populations is a key feature to take into account when exploring genetic risk factors related to this disease.

Yeast model for evaluating the pathogenic significance of SDHB, SDHC and SDHD mutations in PHEO-PGL syndrome.

SDH genes, encoding succinate dehydrogenase, act as tumour suppressor genes, linking mitochondrial dysfunction with tumourigenesis. Heterozygous germline mutations in SDHA, SDHB, SDHC, SDHD and in the assembly factor encoding gene SDHAF2 have all been shown to predispose to heritable endocrine neoplasias such as pheochromocytomas (PHEO) and paragangliomas (PGLs) called 'PHEO-PGL syndrome'. SDH genes mutations, in addition to deletions or truncations which are most likely pathogenic, often include missense substitutions which can be of uncertain significance. Unclassified missense substitutions may be difficult to interpret unless the cause-effect link between mutation and the disease is established by functional and in silico studies or by the familial segregation with the phenotype. Using the yeast model, here, we report functional investigations on several missense SDH mutations found in patients affected by pheochromocytomas or paragangliomas. The aim of this study was to evaluate whether and to which extent the yeast model may be useful for establishing the pathological significance of missense SDH mutations in humans. The results of our study demonstrate that the yeast is a good functional model to validate the pathogenic significance of SDHB missense mutations while, for missense mutations in SDHC and SDHD genes, the model can be informative only when the variation involves a conserved residue in a conserved domain.

Alliance Against Cancer, the network of Italian cancer centers bridging research and care.

Alliance Against Cancer (ACC) was established in Rome in 2002 as a consortium of six Italian comprehensive cancer centers (Founders). The aims of ACC were to promote a network among Italian oncologic institutions in order to develop specific, advanced projects in clinical and translational research. During the following years, many additional full and associate members joined ACC, that presently includes the National Institute of Health, 17 research-oriented hospitals, scientific and patient organizations. Furthermore, in the last three years ACC underwent a reorganization process that redesigned the structure, governance and major activities. The present goal of ACC is to achieve high standards of care across Italy, to implement and harmonize principles of modern personalized and precision medicine, by developing cost effective processes and to provide tailored information to cancer patients. We herein summarize some of the major initiatives that ACC is currently developing to reach its goal, including tumor genetic screening programs, establishment of clinical trial programs for cancer patients treated in Italian cancer centers, facilitate their access to innovative drugs under development, improve quality through an European accreditation process (European Organization of Cancer Institutes), and develop international partnerships. In conclusion, ACC is a growing organization, trying to respond to the need of networking in Italy and may contribute significantly to improve the way we face cancer in Europe.

Impressive response to denosumab in a patient with bone metastatic adenocarcinoma of the stomach after 2 years of zoledronic acid.

Bone is a common site for tumor spread in patients with solid tumors. So far bisphosphonates have been the main pharmacological treatment option for patients with bone metastases. We present a case of bone metastatic gastric cancer treated with zoledronic acid at first and later with denosumab. After 1 year of denosumab treatment, the 18F-fluorodeoxyglucose (18F-FDG)-PET/computed tomography scan reassessment documented a metabolic complete response, even in the absence of specific antiblastic treatment. Whether denosumab can be used directly after pretreatment with bisphosphonates has yet to be addressed.

Optimal follow-up intervals in active surveillance of renal masses in patients with von Hippel-Lindau disease.

OBJECTIVES: To estimate an optimal follow-up (FU) interval for von Hippel-Lindau (VHL) patients with renal masses (RMs) by determining tumour growth rates from growth curves. METHODS: Thirty lesions (47.6%) were classified as solid tumours (STs) and 33 (52.4%) as complex cysts (CCs). Variations in lesion volume over time were analyzed. For 53 lesions, we calculated the growth rate during the period when the volume of the lesion changed most rapidly, and called this the fast growth rate (FGR). RESULTS: The STs initially grew fast, followed by a period of slower growth. The CCs varied in volume over time, associated with variable amounts of their fluid component. The FGR correlated better with the latest volume for STs (r = 0.905) than for CCs (r = 0.780). An optimal FU interval between 3 and 12 months was derived by combining the FGR calculated from the curve with the latest volume measured. CONCLUSIONS: Analyzing growth curves and related kinetic parameters for RMs in VHL patients could be useful with a view to optimizing the subsequent FU interval and improving the active surveillance program. KEY POINTS: • Measuring volume changes over time enables tumour growth curves to be charted. • Renal solid tumours increase in volume with a typical sigmoidal curve. • Complex cysts may increase and decrease in volume spontaneously over time. • The fast growth rate of solid tumours correlates with their latest volume. • The fast growth rate can orient the scheduling of subsequent follow-ups.

Opposing effects of HIF1α and HIF2α on chromaffin cell phenotypic features and tumor cell proliferation: Insights from MYC-associated factor X.

Pheochromocytomas and paragangliomas (PPGLs) are catecholamine-producing chromaffin cell tumors with diverse phenotypic features reflecting mutations in numerous genes, including MYC-associated factor X (MAX). To explore whether phenotypic differences among PPGLs reflect a MAX-mediated mechanism and opposing influences of hypoxia-inducible factor (HIF)s HIF2α and HIF1α, we combined observational investigations in PPGLs and gene-manipulation studies in two pheochromocytoma cell lines. Among PPGLs from 140 patients, tumors due to MAX mutations were characterized by gene expression profiles and intermediate phenotypic features that distinguished these tumors from other PPGLs, all of which fell into two expression clusters: one cluster with low expression of HIF2α and mature phenotypic features and the other with high expression of HIF2α and immature phenotypic features due to mutations stabilizing HIFs. Max-mutated tumors distributed to a distinct subcluster of the former group. In cell lines lacking Max, re-expression of the gene resulted in maturation of phenotypic features and decreased cell cycle progression. In cell lines lacking Hif2α, overexpression of the gene led to immature phenotypic features, failure of dexamethasone to induce differentiation and increased proliferation. HIF1α had opposing actions to HIF2α in both cell lines, supporting evolving evidence of their differential actions on tumorigenic processes via a MYC/MAX-related pathway. Requirement of a fully functional MYC/MAX complex to facilitate differentiation explains the intermediate phenotypic features in tumors due to MAX mutations. Overexpression of HIF2α in chromaffin cell tumors due to mutations affecting HIF stabilization explains their proliferative features and why the tumors fail to differentiate even when exposed locally to adrenal steroids.

Differential gene expression of medullary thyroid carcinoma reveals specific markers associated with genetic conditions.

Medullary thyroid carcinoma accounts for 2% to 5% of thyroid malignancies, of which 75% are sporadic and the remaining 25% are hereditary and related to multiple endocrine neoplasia type 2 syndrome. Despite a genotype-phenotype correlation with specific germline RET mutations, knowledge of pathways specifically associated with each mutation and with non-RET-mutated sporadic MTC remains lacking. Gene expression patterns have provided a tool for identifying molecular events related to specific tumor types and to different clinical features that could help identify novel therapeutic targets. Using transcriptional profiling of 49 frozen MTC specimens classified as RET mutation, we identified PROM1, LOXL2, GFRA1, and DKK4 as related to RET(M918T) and GAL as related to RET(634) mutation. An independent series of 19 frozen and 23 formalin-fixed, paraffin-embedded (FFPE) MTCs was used for validation by RT-qPCR. Two tissue microarrays containing 69 MTCs were available for IHC assays. According to pathway enrichment analysis and gene ontology biological processes, genes associated with the MTC(M918T) group were involved mainly in proliferative, cell adhesion, and general malignant metastatic effects and with Wnt, Notch, NFκB, JAK/Stat, and MAPK signaling pathways. Assays based on silencing of PROM1 by siRNAs performed in the MZ-CRC-1 cell line, harboring RET(M918T), caused an increase in apoptotic nuclei, suggesting that PROM1 is necessary for survival of these cells. This is the first report of PROM1 overexpression among primary tumors.

Role of SDHAF2 and SDHD in von Hippel-Lindau associated pheochromocytomas.

BACKGROUND: Pheochromocytomas (PCCs) develop from the adrenal medulla and are often part of a hereditary syndrome such as von Hippel-Lindau (VHL) syndrome. In VHL, only about 30 % of patients with a VHL missense mutation develop PCCs. Thus, additional genetic events leading to formation of such tumors in patients with VHL syndrome are sought. SDHAF2 (previously termed SDH5) and SDHD are both located on chromosome 11q and are required for the function of mitochondrial complex II. While SDHAF2 has been shown to be mutated in patients with paragangliomas (PGLs), SDHD mutations have been found both in patients with PCCs and in patients with PGLs. MATERIALS AND METHODS: Because loss of 11q is a common event in VHL-associated PCCs, we aimed to investigate whether SDHAF2 and SDHD are targets. In the present study, 41 VHL-associated PCCs were screened for mutations and loss of heterozygosity (LOH) in SDHAF2 or SDHD. Promoter methylation, as well as mRNA expression of SDHAF2 and SDHD, was studied. In addition, immunohistochemistry (IHC) of SDHB, known to be a universal marker for loss of any part the SDH complex, was conducted. RESULTS AND CONCLUSIONS: LOH was found in more than 50 % of the VHL-associated PCCs, and was correlated with a significant decrease (p < 0.05) in both SDHAF2 and SDHD mRNA expression, which may be suggestive of a pathogenic role. However, while SDHB protein expression as determined by IHC in a small cohort of tumors was lower in PCCs than in the surrounding adrenal cortex, there was no obvious correlation with LOH or the level of SDHAF2/SDHD mRNA expression. In addition, the lack of mutations and promoter methylation in the investigated samples indicates that other events on chromosome 11 might be involved in the development of PCCs in association with VHL syndrome.

Spectrum of magnetic resonance imaging findings in pancreatic and other abdominal manifestations of Von Hippel-Lindau disease in a series of 23 patients: a pictorial review.

CONTEXT: Von Hippel Lindau disease is a rare autosomal dominantly inherited multisystem disorder characterized by development of benign and malignant tumors. The abdominal manifestation of the syndrome are protean. Magnetic resonance plays an important role in identification of abdominal abnormalities and follow-up of lesions. OBJECTIVE: To describe magnetic resonance imaging findings and patterns of pancreatic and other principal abdominal manifestations in a series of von Hippel-Lindau (VHL) disease patients and to review literature. METHODS: We retrospectively reviewed abdominal magnetic resonance studies performed in 23 patients (10 males, 13 females) diagnosed of VHL. RESULTS: In all examined patients abdominal involvement was present. The pancreatic imaging findings detected were: unilocular cystic lesions (6/23: 26.1%); serous cystadenomas (11/23: 47.8%), including diffuse lesions (8/23: 34.8%); solid neuroendocrine tumors (8/23: 34.8%); cystic neuroendocrine tumors (1/23: 4.3%). The renal findings detected were: simple renal cysts (18/23: 78.3%); complex renal cysts (13/23: 56.5%), including benign lesions (10/23: 43.5%) and malignant lesions (3/23: 13.0%); renal carcinomas (11/23: 47.8%) and 5 of these (45.5%) were multiple and bilateral. Five patients (21.7%) presented pheochromocytoma (4 of these were bilateral; 80.0%) and 1 patient (4.3%) presented cystadenoma of the epididymis. CONCLUSIONS: In VHL disease patients, magnetic resonance imaging plays an essential role in the identification of pancreatic and other abdominal lesions, in their follow-up, in the screening of asymptomatic gene carriers, and in their long-term surveillance.

Regulation of epinephrine biosynthesis in HRAS-mutant paragangliomas.

The biochemical phenotype of paragangliomas (PGLs) is highly dependent on the underlying genetic background and tumor location. PGLs at extra-adrenal locations usually do not express phenylethanolamine N-methyltransferase (PNMT), the enzyme required for epinephrine production, which was explained by the absence of glucocorticoids. PGLs with pathogenic variants (PVs) in Harvey rat sarcoma viral oncogene homolog (HRAS) can occur in or outside of the adrenal, but always synthesize epinephrine independently of the localization. Here, we characterize the signaling pathways through which PVs in HRAS influence PNMT expression. Catecholamines, cortisol, and transcriptional features of PGL tissues with known genetic background were analyzed. Genetically modified rat pheochromocytoma cells carrying PVs in Hras were generated and analyzed for regulation of Pnmt expression. Elevated epinephrine contents in PGLs with PVs in HRAS were accompanied by enrichment in mitogen-activated protein kinase (MAPK) signaling compared to PGLs with PVs in genes that activate hypoxia pathways. In vitro, Hras PVs increased Pnmt expression and epinephrine biosynthesis through increased phosphorylation of stimulatory protein 1 via MAPK signaling. Here, we provide a molecular mechanism that explains the PV-dependent epinephrine production of PGLs.