Imaging of Pheochromocytoma and Paraganglioma

Case Series of Patients With FGFR1-Related Pheochromocytoma and Paraganglioma With a Focus on Biochemical, Imaging Signatures and Treatment Options

Pheochromocytoma and paraganglioma (together PPGL) are tumours with a high degree of heritability. Genetic landscape is divided into three clusters, cluster 1 (Krebs/pseudohypoxia signalling pathway), cluster 2 (kinase signalling pathway) and cluster 3 (Wnt signalling pathway). With increasing knowledge in the field of genetics, cluster-specific tumour characteristics, biochemical phenotype and imaging signatures are established in commonly found genes. The association of FGFR1 pathogenic mutations with PPGL have been recently described although its features are not yet well established. Here, we present four patients with PPGL who were found to have somatic FGFR1 pathogenic mutations. We discuss their clinical presentations, biochemical phenotypes, imaging signatures and treatment options that will be relevant for practicing physicians in managing these patients effectively.

Comprehensive Head-to-Head Study between Meta-[211At]astato-benzylguanidine and with Meta-[131I]iodo-benzylguanidine in Pheochromocytoma

Pheochromocytoma (PCC) is a rare neuroendocrine tumor that is often nonfunctional in its early stages, making detection difficult during the prodromal phase. Targeted radionuclide therapy using radiopharmaceuticals has been explored for treating PCC. We aimed to evaluate and compare the therapeutic efficacy of meta-[131I]iodobenzylguanidine ([131I]MIBG) and meta-[211At]astatobenzylguanidine ([211At]MABG) in vitro and in a PCC animal model. Astatine-211 was radiolabeled with a benzylguanidine precursor, and the crude product was purified using high-performance liquid chromatography, followed by formulation to prepare an injectable [211At]MABG. [131I]MIBG was obtained from the Korea Atomic Energy Research Institute. The stability of [211At]MABG was assessed in saline and human serum with or without sodium ascorbate. In vitro experiments included evaluating cellular uptake in PC-12 cells, colony formation inhibition (clonogenic assay), and DNA damage (Comet assay). In vivo studies were conducted using PC-12 tumor-bearing mice to assess biodistribution, tumor volume reduction, survival rates, and body weight changes. Immunohistochemical analyses of tumor proliferation and apoptosis were performed using Ki-67, proliferating cell nuclear antigen (PCNA), and the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. [211At]MABG was successfully synthesized with a radiochemical yield of 48.4% (decay-corrected). The radiochemical purity (RCP) was 99.3%, and the specific activity was 1.27-8.13 MBq·nmol-1 at the end of synthesis (n = 3). In chemical stability tests of [211At]MABG, when sodium ascorbate was not added, the RCP was 76% at 24 h after production; however, when sodium ascorbate was added, its purity was 92% at the same time. In vitro uptake assays revealed that [211At]MABG exhibited higher cellular uptake in PC-12 cells compared with [211At]NaAt and [131I]MIBG, initially accumulating in the cytosol and progressively increasing over 24 h. DNA double-strand breaks were confirmed using the Comet assay. Biodistribution studies demonstrated that administration of [211At]MABG containing sodium ascorbate reduced thyroid uptake and enhanced tumor accumulation of [211At]MABG. Treatment with 0.93 MBq [211At]MABG resulted in superior tumor suppression compared with 19.25 MBq [131I]MIBG and improved survival rates. Immunohistochemical analyses confirmed decreased tumor proliferation and increased apoptosis following [211At]MABG treatment. The stability of [211At]MABG in human serum was significantly enhanced by sodium ascorbate. Even at doses 20 times lower than [131I]MIBG, [211At]MABG demonstrated superior antitumor efficacy without inducing substantial weight loss. These findings suggest that [211At]MABG may serve as a promising alternative for treating malignant PCC.

Machine Learning Model for Predicting Pheochromocytomas/Paragangliomas Surgery Difficulty: A Retrospective Cohort Study

OBJECTIVE

We aimed to develop a machine learning (ML) model to preoperatively predict surgical difficulty for pheochromocytomas and paragangliomas (PPGLs) using clinical and radiomic features.

METHODS

In this study, 212 patients with pathologically confirmed PPGLs were retrospectively enrolled and divided into training (n = 148) and validation cohorts (n = 64). Seven ML models (Classification and Regression Tree, K-Nearest Neighbors, Least Absolute Shrinkage and Selection Operator, Naïve Bayes, Random Forest, Support Vector Machine (SVM), and Extreme Gradient Boosting) were trained using clinical parameters alone or combined with radiomics. Model performance was evaluated and compared through accuracy, sensitivity, specificity, F1 score, area under the curve (AUC), calibration curves, and decision curve analysis. Through comprehensive assessment, the optimal integrated model (clinical + radiomics) was identified and its predictive efficacy was subsequently compared with that of the clinical parameter model. Finally, SHapley Additive exPlanations (SHAP) was applied to enhance the interpretability of the optimal model by visualizing feature contributions.

RESULTS

Among all integrated models, the SVM model exhibited the most prominent performance, achieving AUC values of 0.96 in the training cohort and 0.85 in the validation cohort, while demonstrating statistically significant superiority over the clinical parameter model (p < 0.05). The SHAP analysis revealed that radiomic signature (Rad score) exerted the most substantial influence on the predictive outcomes, with age, body mass index, maximum tumor diameter, and preoperative heart rate also demonstrating statistically significant contributions to the model predictions.

CONCLUSION

The SVM model integrating clinical and radiomic features effectively predicts PPGL surgical difficulty, aiding preoperative risk stratification and personalized surgical planning to reduce operative risks.

DNMT3B promotes the progression of pheochromocytoma by mediating the hypermethylation of LRP1B promoter

BACKGROUND

Pheochromocytoma (Pheo) represents a potential metastatic neuroendocrine tumor. As a tumor suppressor gene, LRP1B is involved in the regulation of tumor progression. However, the precise regulatory mechanism of LRP1B in Pheo remains elusive.

METHODS

RT-QPCR, western blot and immunohistochemistry (IHC) were used to identify the expression levels of DNMT3B and LRP1B. Biochemistry assays including luciferase and ChIP were utilized to detect the interaction between the methyltransferase DNMT3B and LRP1B promoter. LRP1B or DNMT3B were knock-down in Pheo cell line by shRNAs. Functional experiments including clonal formation, migration, and in vivo transplantation were performed to evaluate the regulation of LRP1B or DNMT3B on tumor growth.

RESULTS

LRP1B was down-regulated, while DNMT3B was up-regulated in Pheo.Overexpression of LRP1B or inhibition of DNMT3B inhibited the progress of Pheo. DNMT3B was responsible for the hypermethylation of LRP1B promoter in Pheo. At the same time, overexpression of DNMT3B reversed the inhibitory effect of overexpression of LRP1B on Pheo progression.

CONCLUSION

DNMT3B mediated the hypermethylation of the tumor suppressive gene LRP1B and promotes Pheo progression.

Current Strategies for Managing Pheochromocytoma and Paraganglioma in Children and Adolescents

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors that are an important cause of secondary hypertension. The most frequently reported symptom is persistent hypertension, exceeding paroxysmal hypertension. In children with elevated blood pressure, secondary hypertension should always be considered and investigated. These tumors exhibit a wide variety of clinical presentations, including syndromic presentations and life-threatening hypertensive crises. Recent advancements in genetic analysis have identified a growing number of pathogenic mutations. In the pediatric population, 70-80% of tumors exhibit germline mutations in known genes, predisposing children to metastatic and multifocal disease. The diagnosis and treatment remain challenging and often require a multidisciplinary approach at a highly specialized center. Plasma-free metanephrines measurement is considered the criterion standard for diagnosis due to its high sensitivity and reliable pediatric reference values. Functional imaging is helpful for pheochromocytoma and paraganglioma due to its high sensitivity and specificity, and it plays a crucial role in assessing regional extension, multifocality, and the presence of metastases, which are more frequently reported in children. Following definitive diagnosis and appropriate perioperative management, surgery remains the primary treatment. Genetic testing and counseling should be considered in all pediatric patients with confirmed pheochromocytoma and paraganglioma. Evidence and clinical trials in children are limited; therefore, the present report aims to review the presentation, associations, diagnosis, and management of pheochromocytoma and paraganglioma in children and adolescents.

Von Hippel-Lindau syndrome: clinical features, genetic foundations, and management strategies

Von Hippel-Lindau Syndrome (VHL) is a rare, hereditary disorder characterized by the development of multiple tumors and cysts in various parts of the body due to mutations in the VHL gene on chromosome 3p25-26. Patients with VHL are at increased risk for hemangioblastomas of the brain, spinal cord, and retina, renal cell carcinomas, pheochromocytomas, pancreatic neuroendocrine tumors, and endolymphatic sac tumors. Clinical manifestations vary widely, and early diagnosis through genetic testing and regular surveillance is crucial for effective management. Treatment involves monitoring for tumor development, surgical removal of tumors, and targeted therapies for advanced cases. Recent advances in understanding the VHL pathway have led to new targeted treatments, particularly those involving the hypoxia-inducible factors and vascular endothelial growth factor pathways, which have improved patient outcomes. This article reviews the clinical features, genetic foundations, genotype/phenotype relationship and current management strategies for VHL, emphasizing recent advances that have enhanced prognosis and quality of life for patients.

Fumarate Hydratase-Deficient Renal Cell Carcinoma With Paraganglioma Detected on 18 F-FDG PET/CT

ABSTRACT

We report FDG PET/CT findings of fumarate hydratase-deficient renal cell carcinoma coincidence with para-aortic paraganglioma in a 27-year-old man. He presented with painless gross hematuria for 3 days. CT identified an enhancing lesion in the left kidney, suggestive of a tumor. 18 F-FDG PET/CT imaging showed the mass with high FDG uptake. An adjacent FDG-avid nodule was also noted. Postoperative pathology supported a diagnosis of fumarate hydratase-deficient renal cell carcinoma of the left kidney mass, and the adjacent nodule was paraganglioma.

Clinical exome next‑generation sequencing panel for hereditary pheochromocytoma and paraganglioma diagnosis

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors with an annual incidence of ~2 cases per million worldwide. The hereditary form is more likely to present in younger patients. To date, PPGL is considered a complex pathology that is difficult to diagnose. The present study aimed to improve the molecular diagnosis and other driver mutations related to PPGLs using TruSight One clinical exome panel (Illumina, Inc.). The clinical protocol used involved examining 28 patients with suspicion of genetic alterations as the cause of PPGLs. The variants of genes commonly associated with PPGLs (RET, FH, VHL, SDHA, SDHB, SDHC, SDHD, NF1, MAX, HIF2A, TMEM127 and TP53) were filtered across the panel. The libraries were sequenced on a MiSeq instrument (Illumina, Inc.) and the result was ≥20X coverage on 95% of the target regions in the panel, calculated by averaging the mean coverage for each exon. The results of sequencing detected 7% of pathogenic variants in the 18-40 years age subgroup and 11% in the 41-59 years age subgroup, whereas no pathogenic/likely pathogenic variants were identified in patients ≥60 years old. The identification of a germline mutation in patients with apparently sporadic PPGLs could lead to an early diagnosis of multiple or more aggressive tumors, or other neoplastic syndromes, in patients. Furthermore, this information may improve the development of targeted primary and secondary prevention programs tailored to these high-risk groups.

Diagnostic Performance of [18 F] FDOPA PET/CT and Other Tracers in Pheochromocytoma: A Meta-Analysis

RATIONALE AND OBJECTIVES

PET-CT is extensively used in the diagnosis of pheochromocytoma (PHEO). However, various PET-CT tracers are recommended for the diagnosis of PHEO. Therefore, this study evaluated the diagnostic performance of all tracers currently used in the PET-CT detection of PHEO.

METHODS

Studies were retrieved from PubMed, Web of Science, Embase, and Cochrane Library from inception to Feb. 7, 2024. The studies were screened according to the eligibility criteria and the data were extracted. Quality of the included studies was evaluated by the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the summary receiver operating characteristic (sROC) curve (AUC) were pooled in Stata 15, and diagnostic accuracy was pooled in R 4.3.3.

RESULTS

Sixteen studies were included in the meta-analysis. The sensitivity and specificity of [18 F]FDOPA PET/CT for initial PHEO diagnosis were 97% (95% CI: 91%-99%, I2 = 46.14%, p > 0.01) and 94% (95% CI: 86%-98%, I2 = 87.90%, p < 0.01), respectively. The AUC was 0.99 (95% CI: 0.98-1.00). The diagnostic accuracy of [18 F]FDOPA PET/CT was 98.9% (95% CI: 95%-100%) for PHEO patients and 89.7% (95% CI: 85.4%-92.8%) for PHEO lesions. [68Ga]DOTATATE PET/CT had a diagnostic accuracy of 86.9% (95% CI: 78.2%-93.9%) for PHEO and 87.5% (95% CI: 70.3%-95.4%) for PHEO lesions. FDG PET/CT had a diagnostic accuracy of 85.2% (95% CI: 73.6%-94.1%) for PHEO and 86.8% (95% CI: 73%-94.2%) for PHEO lesions. [68Ga]DOTANOC PET/CT had a diagnostic accuracy of 79.3% (95% CI: 49.2%-98.3%) for PHEO.

CONCLUSIONS

In general, PET/CT demonstrates superior performance in the diagnosis of PHEO. In addition, [18 F]FDOPA PET/CT has the best diagnostic performance in PHEO compared with other tracers. Given the limited research on other PET/CT tracers and the potential constraints on their widespread use, additional multicenter and multiregional studies are warranted to further evaluate their diagnostic performance and provide recommendations for clinical use.

Update on the diagnosis of the pheochromocytoma

Pheochromocytoma is a rare neuroendocrine tumour that develops from chromaffin cells in the adrenal medulla and is characterised by the excessive production of catecholamines and their metabolites. Diagnostic confirmation is performed by detecting elevated levels of catecholamines and/or their metabolites in plasma or 24-h urine. In the case of moderate elevations of normetanephrine, the clonidine suppression test may be useful to differentiate between endogenous hypersecretion and false positive results. Once the biochemical diagnosis is performed, the tumour localisation is carried out using imaging techniques and sometimes with nuclear medicine imaging tests. Furthermore, in all patients with pheochromocytomas it is recommended to perform a genetic study to identify hereditary disorders that may be present in more than 30% of cases and to perform a cardiological evaluation to rule out the presence of cardiovascular involvement secondary to the catecholamine hypersecretion.

Comparison of 68Ga-DOTANOC and 18F-FDOPA PET/CT for Detection of Recurrent or Metastatic Paragangliomas

Purpose To evaluate the diagnostic performance of gallium 68 (68Ga)-DOTA-NaI3-octreotide (68Ga-DOTANOC) and fluorine 18 (18F)-fluoro-l-3,4-dihydroxyphenylalanine (18F-FDOPA) PET/CT in detecting recurrent or metastatic paragangliomas. Materials and Methods This single-center retrospective study included patients with paragangliomas who underwent both 68Ga-DOTANOC PET/CT and 18F-FDOPA PET/CT between August 2021 and December 2023. The diagnostic performance of these two tracers in detecting recurrent or metastatic tumors was compared using several metrics, including sensitivity, negative predictive value, and accuracy. Results This study included 36 patients (median age, 52 years [range, 14-78 years]; 16 female, 20 male). Of these, nine underwent initial 68Ga-DOTANOC and 18F-FDOPA PET/CT examinations before treatment, and the remaining 27 underwent posttreatment examinations. Twenty-two of those 27 patients had recurrence or metastasis. According to lesion-level analysis, 68Ga-DOTANOC had higher sensitivity, negative predictive value, and accuracy for diagnosis of bone metastases than did 18F-FDOPA PET/CT (97% vs 78% [P < .001], 85% vs 42% [P = .02], and 97% vs 81% [P < .001], respectively). 18F-FDOPA PET/CT had higher sensitivity, negative predictive value, and accuracy for the diagnosis of liver metastases than did 68Ga-DOTANOC PET/CT (73% vs 15% [P < .001], 68% vs 41% [P = .04], and 83% vs 46% [P < .001], respectively). According to patient-level analysis, the sensitivity of 18F-FDOPA PET/CT for diagnosing liver metastases was higher than that of 68Ga-DOTANOC PET/CT (88% vs 25%; P = .04). Conclusion In patients with recurrent or metastatic paragangliomas, 68Ga-DOTANOC PET/CT showed better performance than 18F-FDOPA PET/CT in detecting bone metastases, and 18F-FDOPA PET/CT performed better in detecting liver metastases. Keywords: 68Ga-DOTANOC, 18F-FDOPA, Pheochromocytoma, Paraganglioma Published under a CC BY 4.0 license.

Mixed functional tumor of the left adrenal as a cause of palpitations, surgical management. Case report

Compound pheochromocytoma refers to a rare adrenal tumor that includes neuroblastic components and is a rare catecholamine-producing tumor from chromaffin cells, typically found in the adrenal medulla. It usually presents with symptoms like tachycardia, headache, and intermittent diaphoresis, although its clinical manifestations can vary. Diagnosis involves biochemical studies and imaging such as catecholamines, metanephrines, CT scans, and positron emission tomography (PET). The surgical management is the definitive, being the laparoscopic approach of choice in most cases. This case report discusses a 45-year-old male who presented with tachycardia and palpitations, diagnosed with left pheochromocytoma exhibiting neuroblastoma differentiation, surgically treated through anterior laparoscopy without any trans-surgical complications and with low bleeding. Postoperative recovery was uneventful, and pathology confirmed the diagnosis. Timely diagnosis and surgical removal are crucial, with laparoscopy being the preferred approach for tumor resection.

Primary Paraganglioma Arising From the Maxillary Bone

We present a unique case of primary intraosseous paraganglioma (PGL) originating from maxillary bone. PGL is a neurosecretory neoplasm that arises from cells believed to originate from the neural crest. A 30-year-old woman presented with right facial pain and swelling, along with palpitations. Computed tomography (CT) imaging revealed a 3.3 × 3.1 × 2.3 cm mass in the anterior maxilla, and biochemical results showed elevated plasma dopamine, 3-methoxytyramine, and chromogranin A levels. Biopsy confirmed a PGL, with positive expression of synaptophysin, chromogranin A, and GATA-3. Whole-body positron emission tomography/computed tomography (PET/CT) scans showed avidity on 18F-fluorodopa (18F-FDOPA), 68Ga-DOTA(0)-Tyr(3)-octreotate ​​ (68Ga-DOTATATE), and 18F-fluorodeoxyglucose (18F-FDG). No other lesions (primary or metastatic) were found. Proton beam therapy was chosen over surgery due to potential complications and patient's preference. Following radiotherapy, she experienced symptom relief, with dopamine levels decreasing and chromogranin A normalizing, with the lesion remaining stable on 11-month follow-up imaging. This case highlights the rarity of primary bone PGLs and underscores the importance of comprehensive diagnostic approaches combining physical examinations, biochemical testing, functional imaging, and histopathological analysis properly guiding personalized treatment strategies. Additionally, proton beam therapy emerges as a highly suitable treatment option for head and neck paragangliomas (HNPGLs), offering effective tumor control with minimal complications.

18F-FDG PET/CT and 68Ga-DOTATATE PET/CT Findings of Polycystic Kidney-derived Paraganglioma

Paragangliomas (PGLs) are neuroendocrine tumors originating from the neural crest. They usually arise from the adrenal medulla and sympathetic or parasympathetic ganglions. Approximately 10% of PGLs are located in the extra-adrenal gland. Renal PGL is a rare condition. In this case report, we present the 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and 68Ga-DOTATATE PET/CT findings of polycystic kidney-derived PGL.

Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma

OBJECTIVE

To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)-related spinal bone metastases.

MATERIALS AND METHODS

Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported.

RESULTS

Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03).

CONCLUSIONS

[68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate.

CLINICAL RELEVANCE STATEMENT

In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001).

KEY POINTS

• Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

Case Series: ATRX Variants in Four Patients with Metastatic Pheochromocytoma

Few reports have highlighted the rare presence of somatic ATRX variants in clinically aggressive, metastatic pheochromocytoma/paraganglioma (PCC/PGL); however, none have addressed detailed clinical presentation (including biochemistry and imaging) and management of these patients. Here, we address these clinical features and management based on four PCC patients with somatic ATRX variants from our National Institutes of Health PCC/PGL cohort. A total of 192 patients underwent exome sequencing (germline, somatic, or both), and four males were found to have somatic ATRX variants (with additional somatic VHL and FH oncogenic variants in patients 2 and 4, respectively). Per-lesion and per-patient comparisons were performed among functional imaging scans performed at the NIH. Biochemical phenotype and response to systemic treatment were evaluated. This mini-series supports prior studies showing aggressive/metastatic PCC in patients with somatic ATRX variants, as all developed widespread metastatic disease. All four PCC patients presented with noradrenergic biochemical phenotype, and some with significant elevation in 3-methoxytyramine. 18F-FDOPA PET/CT was found to be the superior functional imaging modality, with 100% lesion detection rate when compared to that of 68Ga-DOTATATE, 18F-FDG, 18F-FDA, and 123I-MIBG scans. While patients did not respond to chemotherapy or tyrosine kinase inhibitors, they responded to targeted radiotherapy using high-specific-activity 131I-MIBG (Azedra®) or 177Lu-DOTATATE (Lutathera®).

Approach to the Patient: Concept and Application of Targeted Radiotherapy in the Paraganglioma Patient

Paragangliomas can metastasize, posing potential challenges both in symptomatic management and disease control. Systemic targeted radiotherapies using 131I-MIBG and 177Lu-DOTATATE are a mainstay in the treatment of metastatic paragangliomas. This clinical scenario and discussion aim to enhance physicians' knowledge of the stepwise approach to treat these patients with paraganglioma-targeted radiotherapies. It comprehensively discusses current approaches to selecting paraganglioma patients for targeted radiotherapies and how to choose between the two radiotherapies based on specific patient and tumor characteristics, when either therapy is feasible, or one is superior to another. The safety, efficacy, toxicity profiles, and optimization of these radiotherapies are also discussed, along with other therapeutic options including radiotherapies, available for patients besides these two therapies. Perspectives in radiotherapies of paraganglioma patients are outlined since they hold promising approaches in the near future that can improve patient outcomes.

Management of Pheochromocytomas and Paragangliomas

Pheochromocytomas and paragangliomas are distinctive neuroendocrine tumors which frequently produce excess catecholamines with resultant cardiovascular morbidity. These tumors have a strong genetic component, with up to 40% linked to hereditary pathogenic variants; therefore, germline genetic testing is recommended for all patients. Surgical resection offers the only potential cure in the case of localized disease. Given the potential for catecholaminergic crises, appropriate perioperative management is crucial, and all patients should undergo alpha-adrenergic blockade before resection. Therapeutic options for metastatic disease are limited and include surgical debulking, radiopharmaceutical therapies, and conventional chemotherapy.

Malignant paraganglioma of the prostate invading the bladder and bilateral seminal vesicles: a case report

Malignant paraganglioma (PGL) of the prostate is extremely rare, with only 3 cases reported in the English literature to date. In this article, we present a case of malignant prostatic PGL invading the bladder and bilateral seminal vesicles, in which the patient had a history of long-term haematuria and normal serum prostate specific antigen (PSA) level, and was misdiagnosed as a bladder tumour invading the prostate preoperatively. As this case belongs to functional tumour, there is a risk of developing hypertensive crisis during diagnostic biopsy or radical resection. The CT manifestations of prostatic PGL are characteristic, but its imaging features are rarely described due to the rarity of the tumour site. Meanwhile, improving the comprehensive understanding of CT, MRI, functional imaging, and clinical features of prostate PGL is conducive to make the correct diagnosis before surgery and ensure the safety of surgical treatment.

Somatostatin receptor subtype 2A expression and genetics in 184 paragangliomas: a single center retrospective observational study

PURPOSE

Adrenal and extra-adrenal paragangliomas (PGLs) are a group of neuroendocrine tumors (NETs) with strong heterogeneity, which often express somatostatin receptor subtype 2 A (SSTR2A). However, the association between SSTR2A expression and genetic status of PGLs remains unclear. The purpose of the study was to identify whether various pathogenic variants (PVs) had an impact on SSTR2A expression in PGLs.

METHODS

This retrospective study included 184 patients with pathologically confirmed PGLs. The immunohistochemical expression of SSTR2A were studied in 184 tumors and PVs were tested in 159 tumor samples. Clinical and genetic data were compared in SSTR2A positive and negative PGLs.

RESULTS

SSTR2A was positive in 63.6% (117/184) of all tumors. PGLs with negative SSTR2A were more likely to be extra-adrenal (37.0% vs 18.0%; P = 0.005) and exhibited a considerably greater proportion of PVs (75.4% vs. 49.0%; P = 0.001) than those with positive SSTR2A. Compared to those without PVs, a higher proportion of PGLs with PVs in cluster 1B (P = 0.004) and cluster 2 (P = 0.004) genes, especially VHL (P = 0.009), FGFR1 (P = 0.010) and HRAS (P = 0.007), were SSTR2A negative. SSTR2A was positive in all tumors (4/4) with SDHx PVs and in 87.5% (7/8) of metastatic PGLs.

CONCLUSIONS

SSTR2A negativity was correlated with extra-adrenal tumor location and PVs in cluster 1B and cluster 2 genes such as VHL, FGFR1 and HRAS. Immunohistochemistry of SSTR2A should be taken into consideration in the personalized management of PGLs.

The Radiosurgery Society Case-Based Discussion of the Management of Head and Neck or Skull Base Paragangliomas with Stereotactic Radiosurgery and Radiotherapy

Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) have been used for the treatment of head and neck or skull base paraganglioma for a considerable time, demonstrating promising local control rates and a favorable safety profile compared with surgical approaches. Nevertheless, the choice of treatment must be carefully tailored to each patient's preferences, tumor location, and size, as well as anticipated treatment-related morbidity. This case-based review serves as a practical and concise guide for the use of SRS and FSRT in the management of head and neck or skull base paragangliomas, providing information on the diagnosis, treatment, follow-up considerations, and potential pitfalls.

Theranostics in Neuroendocrine Tumors

ABSTRACT

Neuroendocrine tumors (NETs) are rare tumors that develop from cells of the neuroendocrine system and can originate in multiple organs and tissues such as the bowels, pancreas, adrenal glands, ganglia, thyroid, and lungs. This review will focus on gastroenteropancreatic NETs (more commonly called NETs) characterized by frequent somatostatin receptor (SSTR) overexpression and pheochromocytomas/paragangliomas (PPGLs), which typically overexpress norepinephrine transporter. Advancements in SSTR-targeted imaging and treatment have revolutionized the management of patients with NETs. This comprehensive review delves into the current practice, discussing the use of the various Food and Drug Administration-approved SSTR-agonist positron emission tomography tracers and the predictive imaging biomarkers, and elaborating on 177Lu-DOTATATE peptide receptor radionuclide therapy including the evolving areas of posttherapy imaging practices and peptide receptor radionuclide therapy retreatment. SSTR-targeted imaging and therapy can also be used in patients with PPGL; however, this patient population has demonstrated the best outcomes from norepinephrine transporter-targeted therapy with 131I-metaiodobenzylguanidine. Metaiodobenzylguanidine theranostics for PPGL will be discussed, noting that in 2024 it became commercially unavailable in the United States. Therefore, the use and reported success of SSTR theranostics for PPGL will also be explored.

Overview of F18-FDG uptake patterns in retroperitoneal pathologies: imaging findings, pitfalls, and artifacts

INTRODUCTION

Retroperitoneum can be the origin of a wide variety of pathologic conditions and potential space for disease spread to other compartments of the abdomen and pelvis. Computed tomography (CT) and magnetic resonance imaging (MRI) are often the initial imaging modalities to evaluate the retroperitoneal pathologies, however given the intrinsic limitations, F18-FDG PET/CT provides additional valuable metabolic information which can change the patient management and clinical outcomes. We highlight the features of retroperitoneal pathologies on F18-FDG PET/CT and the commonly encountered imaging artifacts and pitfalls. The aim of this review is to characterize primary and secondary retroperitoneal pathologies based on their metabolic features, and correlate PET findings with anatomic imaging.

CONCLUSION

Retroperitoneal pathologies can be complex, ranging from oncologic to a spectrum of non-oncologic disorders. While crosse-sectional imaging (CT and MRI) are often the initial imaging modalities to localize and characterize pathologies, metabolic information provided by F18-FDG PET/CT can change the management and clinical outcome in many cases.

Case report: Rare case of a preoperatively diagnosed spermatic cord paraganglioma and literature review

Paraganglioma (PGL) is rare, and PGL that arises from the urogenital system is even rarer. Here we report a case of PGL in spermatic cord and review the relevant literatures. We encountered a 15-year-old boy with a history of hypertension for almost 2 years, accompanied with headache and palpitations. His serum and urine catecholamines were elevated, but no adrenal lesions were detected, suggesting the existence of PGL. Upon physical examination, a painless nodule adherent to the spermatic cord in the right scrotum was found. A systemic Ga68 DOTATATE PET-CT was then performed, and it revealed a mass with high DOTATATE uptake in the right scrotum. The CT, MRI, and ultrasound images showed the abundant blood supply to the tumor. Based on the above-mentioned imaging and biochemical information, a diagnosis of PGL was made prior to surgery. After 2 weeks of preparation with Cardura, an open surgery was performed to remove the tumor together with the right testis and right epididymis. The blood pressure increased to 180/100 mmHg when the tumor was touched intraoperatively and decreased to 90/55 mmHg after the tumor was removed. Post-operative pathology confirmed our diagnosis of PGL originating from the spermatic cord. Immunohistochemical (IHC) staining showed SDHB (+), CgA (+), synaptophysin (+), GATA3 (+), CD56 (+), sertoli cells S-100 (+), and Ki67 (5%). Genetic testing revealed a missense mutation in the SDHA gene. Only 16 cases of spermatic cord PGL have been reported to date. Although it is easy to diagnose by histology and IHC examinations, preoperative diagnosis is quite important as it can actually reduce intraoperative complications.

Pitfalls in the Diagnostic Evaluation of Pheochromocytomas

Pheochromocytomas and paragangliomas (PPGLs), rare neuroendocrine tumors arising from chromaffin cells, present a significant diagnostic challenge due to their clinical rarity and polymorphic symptomatology. The clinical cases demonstrate the importance of an integrated approach that combines clinical assessment, biochemical testing, and imaging to distinguish PPGLs from mimicking conditions, such as obstructive sleep apnea and interfering medication effects, which can lead to false-positive biochemical results. Although a rare condition, false-negative metanephrine levels can occur in pheochromocytomas, but imaging findings can give some clues and increase suspicion for a pheochromocytoma diagnosis. This expert endocrine consult underscores the critical role of evaluating preanalytical conditions and pretest probability in the biochemical diagnosis of PPGLs. Moreover, a careful differentiation of PPGLs from similar conditions and careful selection and interpretation of diagnostic tests, with focus on understanding and reducing false positives to enhance diagnostic accuracy and patient outcomes, is crucial.

Management of phaeochromocytoma and paraganglioma in patients with germline SDHB pathogenic variants: an international expert Consensus statement

Adult and paediatric patients with pathogenic variants in the gene encoding succinate dehydrogenase (SDH) subunit B (SDHB) often have locally aggressive, recurrent or metastatic phaeochromocytomas and paragangliomas (PPGLs). Furthermore, SDHB PPGLs have the highest rates of disease-specific morbidity and mortality compared with other hereditary PPGLs. PPGLs with SDHB pathogenic variants are often less differentiated and do not produce substantial amounts of catecholamines (in some patients, they produce only dopamine) compared with other hereditary subtypes, which enables these tumours to grow subclinically for a long time. In addition, SDHB pathogenic variants support tumour growth through high levels of the oncometabolite succinate and other mechanisms related to cancer initiation and progression. As a result, pseudohypoxia and upregulation of genes related to the hypoxia signalling pathway occur, promoting the growth, migration, invasiveness and metastasis of cancer cells. These factors, along with a high rate of metastasis, support early surgical intervention and total resection of PPGLs, regardless of the tumour size. The treatment of metastases is challenging and relies on either local or systemic therapies, or sometimes both. This Consensus statement should help guide clinicians in the diagnosis and management of patients with SDHB PPGLs.

A Woman with Bilateral Pheochromocytoma and Tuberous Sclerosis Complex

Background/Objective

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors. Here, we report an unusual case of synchronous PPGL in an asymptomatic patient with tuberous sclerosis complex (TSC).

Case Report

A 49-year-old woman with a history of TSC and end-stage renal disease was referred for evaluation of bilateral adrenal and retroperitoneal masses. She denied chest pain, palpitations, headaches, or previous hypertensive crisis. The laboratory test results showed a plasma normetanephrine level of 20.20 nmol/L (normal range, 0.00-0.89 nmol/L) and plasma chromogranin A level Chromogranin A (CgA) levels of 1518 ng/mL (normal range, 0-103 ng/mL). The plasma metanephrine level was normal. After α-blockade, the patient underwent bilateral adrenalectomy and retroperitoneal mass excision. Pathology confirmed these lesions to be pheochromocytoma and composite paraganglioma/ganglioneuroma, respectively. Her plasma normetanephrine level normalized postoperatively, and the chromogranin A levels improved to 431 ng/mL.

Discussion

Routine imaging has increased the incidental diagnosis of PPGL. Diagnostic workup includes measurement of the urinary and/or plasma metanephrine and catecholamine levels followed by tumor localization. Patients with young age, syndromic lesions, bilateral PPGL, or unilateral disease with a positive family history should have genetic testing. Definitive treatment is surgical after α-blockade.

Conclusion

This case highlights a rare presentation of bilateral PPGL in a patient with TSC.

Exploring Head and Neck Paraganglioma: A Case Report

Paragangliomas (PGLs) are tumors that are rarely malignant; the majority of them are benign. Similar to pheochromocytoma, they develop from the autonomic nerve system. This system originates from neural crest cells and can undergo neoplastic transformation. PGLs can arise either inside or outside the adrenal glands. Head and neck PGLs are very scarce. The primary locations where this tumor commonly originates within this region are the carotid body, jugular bulb, and vagal body. Hence, in our case report, we attempt to highlight the uncommon presentation of this disease in a 46-year-old female, who initially presented with hypertension and persistent dysphonia. The patient underwent successful external radiotherapy. This case report aims to raise awareness of the characteristics of these rare malignancies.

Aggressive posterior paraganglioma presenting with generalized weakness, anemia, hypertension, and weight loss: A case report

Paragangliomas (PGLs) are rare neuroendocrine tumors that originate from chromaffin cells in the extra-adrenal autonomic nervous system's ganglia. The diagnosis of PGL is made based on clinical characteristics, biochemical tests, imaging, functional studies, and pathology reports. Catecholamines and chromogranin A levels should be evaluated prior to biopsy or surgical excision. We present a case of aggressive PGL in a 55-year-old woman presented with weakness, blurred vision, hypertension, and weight loss.

A rare case report of ectopic-adrenal paraganglioma with inferior vena cava infiltration. Case report and literature review

INTRODUCTION AND IMPORTANCE

Phaeochromocytomas are neuroendocrine neoplasms arising from chromaffin cells of the adrenal medulla and are known as intra-adrenal paragangliomas. On the contrary, paragangliomas are non-epithelial neuroendocrine neoplasms that produce other peptide hormones such as norepinephrine, epinephrine, and dopamine. In a setting with limited resources, such a condition may result in inaccurate diagnosis and treatment, which may lose a patient life if left untreated. In addition, PPGLs present a surgical challenge to many surgeons who are not thoroughly prepared.

CASE PRESENTATION

We describe a case of extra-adrenal paraganglioma in a 27-year-old female who presented with symptoms of heartbeat awareness for almost a year and abdominal swelling for three months. Physical examination revealed a palpable mass around the umbilicus. Abdominal pelvic CT scan revealed a well-circumscribed mass in the central retroperitoneum displacing the IVC laterally and abdominal aorta medially with no invasion of surrounding structures. Results for pheochromocytoma workup showed elevated levels of 24-h urine Vanillylmandelic acid (VMA), and 24-h metanephrine excretion. Laparotomy through extended midline incision was done with successful excision of the tumor. The blood pressure, which was initially high normalized after surgery.

DISCUSSION

The diagnosis of a malignant EAP is commonly made based on recurrence and the development of metastasis to lymph nodes or to other organs. Our patient presented with similar symptoms as pheochromocytoma. Compared to the commonly stated 10 % risk for pheochromocytomas, people with EAPs have been observed to have a 20 % to 50 % incidence of malignancy. EAPs account for at least 15 % of adult and 30 % of pediatric pheochromocytomas and are frequently found in the Zuckerkandl organ. Pheochromocytoma symptoms may manifest asymptomatically in patients with EAPs, or they may occur because of compression of nearby tissues. Surgical excision of the tumor is always the best option in managing EAP.

CONCLUSION

Extra-adrenal paragangliomas can be successfully managed surgically, provided there is a multidisciplinary team, and the tumor location is well recognized and can reduce the chance of tumor metastasis.

A Multidisciplinary Skull Base Board for Tumour and Non-Tumour Diseases: Initial Experiences

The skull base is the area where various cancerous and non-cancerous diseases occur and represents the intersection of several medical fields. The key is an integrated treatment by specialists of multiple disciplines. We prospectively analysed patients with a skull base disease between August 2022 and 2023 and presented to the Multidisciplinary Skull Base Board (MDT-SB), which takes place once a month hybridly (in-person and remotely). Thirty-nine patients (median age of 58.2 years) were included, of which twelve (30.8%) had a benign tumour, twelve (30.8%) had a malignant tumour, five had an infection (12.8%), and ten (25.6%) had other diseases. For each patient, at least two otorhinolaryngologists, a neurosurgeon, and a neuroradiologist, as well as an infectious disease specialist, a paediatrician, an oculoplastic surgeon, a maxillofacial surgeon, and a pathologist were involved in 10%, 8%, 8%, 3%, and 3% of cases, respectively. In fifteen patients (38%), the MDT-SB suggested surgical treatment; in fourteen (36%), radiological follow-ups; in five (13%), non-surgical treatments; in two, conservative treatments (5%); in two (5%), surgical and conservative treatments; and in one (3%), a biopsy. Non-cancerous and cancerous diseases of the skull base in adults and children should be presented to the MDT-SB, which consists of at least an otolaryngologist, a neurosurgeon, and a neuroradiologist.

Mastering bladder paraganglioma for optimal treatment: a case report of robot-assisted surgery

Bladder paraganglioma is a rare neuroendocrine neoplasm, either functional or non-functional, arising from the urinary bladder. Functional variants present with catecholamine-related symptoms, while non-functional variants pose diagnostic challenges, mimicking urothelial carcinoma. Misdiagnosis risks underscore the importance of accurate identification for appropriate patient management. In this case, a 52-year-old man, diagnosed incidentally with hypertension and reported occasional post-micturition tachycardia, underwent abdominal ultrasound for known hepatic cyst follow-up, revealing an oval hypoechoic bladder mass. Initial consideration of bladder urothelial carcinoma prompted further investigation with contrast-enhanced CT scan and cystoscopy that confirmed extrinsic mass nature, and subsequent robotic-assisted partial cystectomy was performed. Histologically, the removed mass exhibited characteristic features of bladder paraganglioma. Postoperative recovery was uneventful, with resolution of post-micturition tachycardia at 1 month. Follow-up includes endocrinological evaluation and a 6-month CT scan. In conclusion, bladder paraganglioma should be considered in para-vesical mass differentials. This case highlights the importance of meticulous history collection, even in asymptomatic patients, the need for a multidisciplinary approach for accurate diagnosis and management of this rare condition, and the robotic approach as a viable option.

Improving susceptibility of neuroendocrine tumors to radionuclide therapies: personalized approaches towards complementary treatments

Radionuclide therapies are an important tool for the management of patients with neuroendocrine neoplasms (NENs). Especially [131I]MIBG and [177Lu]Lu-DOTA-TATE are routinely used for the treatment of a subset of NENs, including pheochromocytomas, paragangliomas and gastroenteropancreatic tumors. Some patients suffering from other forms of NENs, such as medullary thyroid carcinoma or neuroblastoma, were shown to respond to radionuclide therapy; however, no general recommendations exist. Although [131I]MIBG and [177Lu]Lu-DOTA-TATE can delay disease progression and improve quality of life, complete remissions are achieved rarely. Hence, better individually tailored combination regimes are required. This review summarizes currently applied radionuclide therapies in the context of NENs and informs about recent advances in the development of theranostic agents that might enable targeting subgroups of NENs that previously did not respond to [131I]MIBG or [177Lu]Lu-DOTA-TATE. Moreover, molecular pathways involved in NEN tumorigenesis and progression that mediate features of radioresistance and are particularly related to the stemness of cancer cells are discussed. Pharmacological inhibition of such pathways might result in radiosensitization or general complementary antitumor effects in patients with certain genetic, transcriptomic, or metabolic characteristics. Finally, we provide an overview of approved targeted agents that might be beneficial in combination with radionuclide therapies in the context of a personalized molecular profiling approach.

Imaging Pathway of a Pediatric Patient with Succinate Dehydrogenase B-Deficient Paraganglioma

Pheochromocytoma and paraganglioma are rare in children, at only 1 in every 50,000 cases. Even though some cases are sporadic, they have been connected to syndromes such as von Hippel-Lindau, multiple endocrine neoplasia types IIa and IIb, neurofibromatosis type 1, and hereditary pheochromocytoma-paraganglioma syndromes. A genetic mutation causes around 60% of pheochromocytomas and paragangliomas in children under 18. Methods: A 15-y-old child with a 6-y history of back discomfort is presented. The justification for using 2 functional imaging modalities, 68Ga-DOTATATE PET/CT and 123I-meta-iodobenzylguanidine SPECT/CT, is examined in this case study. We reviewed the patients' journey since the first referral for imaging. Results: Delaying the molecular imaging modalities has affected patients' overall diagnosis and applied treatment outcomes. Conclusion: This case study investigates the potential for the earlier use of various diagnostic modalities in conjunction with diagnostic testing to facilitate an earlier diagnosis. However, since this study is based solely on imaging and lacks access to the patient's clinical or family history, factors such as potential inequities in health-care facilities, health literacy, and socioeconomic status are not addressed. It is essential to acknowledge these influences as they contribute to the inequitable access to health-care settings in New Zealand.

Bilateral Pheochromocytoma and Paraganglioma Tumors Due to Von Hippel-Lindau Syndrome in a 15-Year-Old Boy: A Case Report

Pheochromocytomas and paragangliomas are catecholamine-secreting tumors that originate from chromaffin cells of the adrenal medulla and autonomic neural ganglia, respectively. Patients with pheochromocytomas and paragangliomas typically present with paroxysmal headache, sweating, tachycardia, and hypertension. Although most pheochromocytoma cases are sporadic, many of the cases occur as part of a genetic disorder. Here, we report the case of a 14-year-old male patient who presented with hypertension. Laboratory tests showed elevated levels of serum and urinary catecholamines, metanephrines, and chromogranin. Abdominal ultrasound and computed tomography studies revealed bilateral solid adrenal masses and an isolated splenic mass. Further assessment identified an underlying Von Hippel-Lindau syndrome. The patient was initially treated medically and later surgically. This case highlights the importance of always considering pheochromocytomas and paragangliomas as rare differentials of secondary hypertension, especially in the presence of episodic headaches, sweating, and tachycardia. Furthermore, screening for underlying genetic disorders, such as in our case, should be considered in cases of bilateral tumors, onset at a young age, and presence of extra-adrenal tumors.

Image-Guided Precision Medicine in the Diagnosis and Treatment of Pheochromocytomas and Paragangliomas

In this comprehensive review, we aimed to discuss the current state-of-the-art medical imaging for pheochromocytomas and paragangliomas (PPGLs) diagnosis and treatment. Despite major medical improvements, PPGLs, as with other neuroendocrine tumors (NETs), leave clinicians facing several challenges; their inherent particularities and their diagnosis and treatment pose several challenges for clinicians due to their inherent complexity, and they require management by multidisciplinary teams. The conventional concepts of medical imaging are currently undergoing a paradigm shift, thanks to developments in radiomic and metabolic imaging. However, despite active research, clinical relevance of these new parameters remains unclear, and further multicentric studies are needed in order to validate and increase widespread use and integration in clinical routine. Use of AI in PPGLs may detect changes in tumor phenotype that precede classical medical imaging biomarkers, such as shape, texture, and size. Since PPGLs are rare, slow-growing, and heterogeneous, multicentric collaboration will be necessary to have enough data in order to develop new PPGL biomarkers. In this nonsystematic review, our aim is to present an exhaustive pedagogical tool based on real-world cases, dedicated to physicians dealing with PPGLs, augmented by perspectives of artificial intelligence and big data.

Pheochromocytoma presenting with upper abdominal pain and hypertensive crisis: A case report

Pheochromocytoma (PHEO) is a rare and complex molecularly driven endocrine disease that can present with a variety of clinical manifestations, including paroxysmal hypertension, episodic anxiety, tremors, devastating acute heart failure and acute pulmonary edema. The variety of PHEO-related symptoms increase the difficulty of identifying and diagnosing PHEO. We reported a case of a 27-year-old Chinese male was diagnosed PHEO by CT scan because of upper abdominal pain. The patient complicated with hypertensive crisis and headache following his admission, and he was underwent adrenal tumor surgical resection by carrying out appropriate clinical, laboratory and radiological imaging. Thus, the patient's PHEO-related symptoms were relieved and the blood pressure returned to normal, and discharged from the hospital with a follow-up plan. Although the PEHO-related symptoms are varied and difficult to diagnose, CT examination can be used for the preliminary detection and diagnosis. This case report emphasizes the importance of considering PHEO by CT scan and atypical symptoms, which help others better understand PHEO for early detection and timely surgical treatment to reduce catecholamine-related complications.

Functional retroperitoneal paraganglioma invading the inferior vena cava in the elderly, a case report and literature review

INTRODUCTION AND IMPORTANCE

Phaeochromocytomas and paragangliomas are rare neuroendocrine neoplasms that grow outside the adrenal gland and arise from the primitive neural crest cells. The retroperitoneal location is extremely rare with an incidence of 2-8 per million.

CASE PRESENTATION

Here we report a case of an 80 years old man presenting with abdominal pain and vomiting associated with hypertensive peaks and weight loss. CT scan showed a retroperitoneal para-aortic tumor invading the inferior vena cava, with significantly elevated urinary catecholamine levels. Histopathological and immunohistochemistry examinations confirmed the diagnosis of paraganglioma. A medical preparation by alpha-blockers was performed. Complete resection of the tumor with the reconstruction of the vena cava was achieved without postoperative complications. After surgery, blood pressure and HbA1c were on the targets and the urinary catecholamine levels were normal.

CLINICAL DISCUSSION

The diagnosis of paragangliomas is suspected by clinical symptoms in the case of functional paragangliomas and the confirmation is biological by the plasmatic or urinary catecholamines. Non-functional paragangliomas often represent a diagnostic challenge. In our case, the large size, the location of the tumor, and the invasion of adjacent structures represented a surgical challenge to perform a complete resection.

CONCLUSION

In the elderly, this pathology is quite uncommon. Retroperitoneal paraganglioma is a rare location of this type of tumor. Endocrinologists, surgeons, and anesthesiologists should work together to ensure an appropriate diagnosis and treatment of paraganglioma. The gold standard treatment is the complete resection after a medical preparation.

[The clinical value of 123I-metaiodobenzylguanidine myocardial imaging in the diagnosis of dementia with Lewy bodies]

Metaiodobenzylguanidine (MIBG) is an analog of norepinephrine that accumulates in sympathetic nerve endings soon after intravenous administration. The degree of accumulation reflects the uptake, storage and release of transmitters by noradrenergic neurons. Myocardial imaging with 123I labeled MIBG ( 123I-MIBG) can be used to estimate the extent of local myocardial sympathetic nerve damage, which has been widely used in the diagnosis and treatment of various heart diseases. In recent years, numerous studies have been carried out on the application of 123I-MIBG in the diagnosis of degenerative diseases of the nervous system (such as Parkinson's disease and dementia of Lewy body), and have made some achievements. The purpose of this review is to summarize the current clinical application of 123I-MIBG myocardial imaging in the diagnosis of dementia with Lewy bodies, the problems in imaging technology and the possible research directions in the future, so as to provide valuable reference information for clinicians to reasonably and accurately apply this technology in the early diagnosis and discrimination of dementia.

Primary hepatic paraganglioma with megacolon: A case report

Primary hepatic paraganglioma (PGL) is a rare neuroendocrine tumor characterized by clinical manifestations including paroxysmal hypertension, palpitation, abdominal pain and constipation. In the present study, the case of a 21-year-old woman with pathologically confirmed hepatic PGL with megacolon following surgery is reported. The patient initially visited Beijing Tiantan Hospital (Beijing, China) for hypoferric anemia. A triple-phase CT scan of the whole abdomen showed a large hypodense mass with a solid periphery and strong arterial enhancement of the peripheral solid portion of the liver. The sigmoid colon and rectum were obviously distended, filled with gas and intestinal contents. The patient was preoperatively diagnosed with iron deficiency anemia, liver injury and megacolon and then underwent partial hepatectomy, total colectomy and enterostomy. Microscopically, the liver cells exhibited an irregular zellballen pattern. In addition, immunohistochemical staining revealed that liver cells were positive for CD56, chromogranin A, vimentin, S-100, melan-A and neuron-specific enolase. Therefore, the diagnosis of primary PGL of the liver was confirmed. These findings suggested that primary hepatic PGL should not be excluded when megacolon occurs and comprehensive imaging evaluation is of great importance for its diagnosis.

Lutathera® Orphans: State of the Art and Future Application of Radioligand Therapy with 177Lu-DOTATATE

Lutathera® is the first EMA- and FDA-approved radiopharmaceutical for radioligand therapy (RLT). Currently, on the legacy of the NETTER1 trial, only adult patients with progressive unresectable somatostatin receptor (SSTR) positive gastroenteropancreatic (GEP) neuroendocrine neoplasms (NET) can be treated with Lutathera®. Conversely, patients with SSTR-positive disease arising from outside the gastroenteric region do not currently have access to Lutathera® treatment despite several papers in the literature reporting the effectiveness and safety of RLT in these settings. Moreover, patients with well-differentiated G3 GEP-NET are also still “Lutathera orphans”, and retreatment with RLT in patients with disease relapse is currently not approved. The aim of this critical review is to summarize current literature evidence assessing the role of Lutathera® outside the approved indications. Moreover, ongoing clinical trials evaluating new possible applications of Lutathera® will be considered and discussed to provide an updated picture of future investigations.

Paraganglioma in a Young Adult Female Patient: A Case Report

Paragangliomas are catecholamine-secreting neuroendocrine tumors that originate from the chromaffin cells of the sympathetic ganglia. Roughly 10% of paragangliomas are malignant, resulting in a rare occurrence of 90-95 cases per 400 million people. Herein, we report a case of a 29-year-old female patient who presented with nausea, vomiting, and bloating and was found to have a large left retroperitoneal tumor upon imaging. The tumor was successfully removed, and subsequent histological analysis was compatible with the presence of a paraganglioma. This case serves as a reminder that despite its rarity, paragangliomas should never be dismissed as a differential diagnosis if correlating symptoms and diagnostic findings are consistent with that of paraganglioma etiology.

CT Texture Analysis of Adrenal Pheochromocytomas: A Pilot Study

Radiomics is a promising research field that combines big data analysis (from tissue texture analysis) with clinical questions. We studied the application of CT texture analysis in adrenal pheochromocytomas (PCCs) to define the correlation between the extracted features and the secretory pattern, the histopathological data, and the natural history of the disease. A total of 17 patients affected by surgically removed PCCs were retrospectively enrolled. Before surgery, all patients underwent contrast-enhanced CT and complete endocrine evaluation (catecholamine secretion and genetic evaluation). The pheochromocytoma adrenal gland scaled score (PASS) was determined upon histopathological examination. After a resampling of all CT images, the PCCs were delineated using LifeX software in all three phases (unenhanced, arterial, and venous), and 58 texture parameters were extracted for each volume of interest. Using the Mann-Whitney test, the correlations between the hormonal hypersecretion, the malignancy score of the lesion (PASS > 4), and texture parameters were studied. The parameters DISCRETIZED_HUpeak and GLZLM_GLNU in the unenhanced phase and GLZLM_SZE, CONVENTIONAL_HUmean, CONVENTIONAL_HUQ3, DISCRETIZED_HUmean, DISCRETIZED_AUC_CSH, GLRLM_HGRE, and GLZLM_SZHGE in the venous phase were able to differentiate secreting PCCs (p < 0.01), and the parameters GLZLM_GLNU in the unenhanced phase and GLRLM_GLNU and GLRLM_RLNU in the venous differentiated tumors with low and high PASS. CT texture analysis of adrenal PCCs can be a useful tool for the early identification of secreting or malignant tumors.

Clinical utility of nuclear imaging in the evaluation of pediatric adrenal neoplasms

Adrenal neoplasms rarely occur in children. They can be diagnosed in the presence of endocrine, metabolic or neurological problems, an abdominal mass, more rarely an adrenal incidentaloma, or in the context of an adrenal mass discovered in the evaluation of childhood cancer including hematologic malignancy. According to standard medical practice, pediatric malignancies are almost always evaluated by ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography ([¹⁸F]FDG PET/CT). Nuclear imaging using specific radiotracers is also an important tool for diagnosing and staging neuroblastoma, pheochromocytoma, hormone hypersecretion, or indeterminate adrenal masses. The Hippocratic oath "primum non nocere" encourages limitation of radiation in children per the ALARA concept (as low as reasonably achievable) but should not lead to the under-use of nuclear imaging because of the potential risk of inaccurate diagnosis or underestimation of the extent of disease. As in adults, nuclear imaging in children should be performed in conjunction with hormone evaluation and morphological imaging.

18 F-MFBG PET/CT Is an Effective Alternative of 68 Ga-DOTATATE PET/CT in the Evaluation of Metastatic Pheochromocytoma and Paraganglioma

PURPOSE

The current guidelines state that the functional imaging choice in the evaluation of metastatic pheochromocytoma and paraganglioma (PPGL) is 68 Ga-DOTATATE PET/CT. 18 F-meta-fluorobenzylguanidine ( 18 F-MFBG) is a new PET tracer and an analog of meta-iodobenzylguanidine (MIBG). This study aimed to compare 18 F-MFBG and 68 Ga-DOTATATE PET/CT in patients with metastatic PPGL.

PATIENTS AND METHODS

Twenty-eight patients with known metastatic PPGL were prospectively recruited for this study. All patients underwent both 18 F-MFBG and 68 Ga-DOTATATE PET/CT studies within 1 week. Lesion numbers detected were compared between these 2 studies.

RESULTS

18 F-MFBG PET/CT was positive for detecting metastases in all patients, whereas positive results of 68 Ga-DOTATATE PET/CT were in 27 (96.4%) patients. A total of 686 foci of metastatic lesions were detected by both 18 F-MFBG and 68 Ga-DOTATATE imaging. In addition, 33 foci of abnormal activity were only detected by 18 F-MFBG, whereas 16 foci were only shown on 68 Ga-DOTATATE PET/CT.

CONCLUSIONS

Our data suggest that 18 F-MFBG PET/CT is an effective imaging method in the evaluation of metastatic PPGL and could be alternative of 68 Ga-DOTATATE PET/CT in this clinical setting.