An evolving view of complex II-noncanonical complexes, megacomplexes, respiration, signaling, and beyond.

Mitochondrial complex II is traditionally studied for its participation in two key respiratory processes: the electron transport chain and the Krebs cycle. There is now a rich body of literature explaining how complex II contributes to respiration. However, more recent research shows that not all of the pathologies associated with altered complex II activity clearly correlate with this respiratory role. Complex II activity has now been shown to be necessary for a range of biological processes peripherally related to respiration, including metabolic control, inflammation, and cell fate. Integration of findings from multiple types of studies suggests that complex II both participates in respiration and controls multiple succinate-dependent signal transduction pathways. Thus, the emerging view is that the true biological function of complex II is well beyond respiration. This review uses a semichronological approach to highlight major paradigm shifts that occurred over time. Special emphasis is given to the more recently identified functions of complex II and its subunits because these findings have infused new directions into an established field.

Role of epigenetic regulation on catecholamine synthesis in pheochromocytoma and paraganglioma.

INTRODUCTION: Pheochromocytomas and paragangliomas (PPGLs) typically secrete catecholamines and their metabolites (metanephrines [MN] and normetanephrine [NMN]). Catecholamines are synthesized by several enzymes: phenylalanine hydroxylase (encoded by PAH), tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (DDC), dopamine ß-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT). MN/NMN secretion varies between anatomical and molecular subgroups. The aim of this study was to assess the correlation between DNA methylation of catecholamine synthesis genes and MN/NMN secretion. METHODS: Gene promoter methylation of PAH, TH, AADC, DBH, and PNMT were extracted and calculated based on publicly available data. Comparisons and correlation analysis were performed between MN ± NMN (MN/NMN), NMN only, and neither/unknown secretion patterns. Methylation levels and MN/NMN patterns were compared by three genetic alteration subgroups: pseudohypoxia (PH), kinase signaling (KS), and others. RESULTS: A total of 178 cases were included. Methylation of PAH CpGs negatively correlated with probability for MN/NMN secretion (p < .05 for all CpGs) and positively with NMN-only secretion. NMN-only secreting tumors had significantly higher promoter methylation of PAH, DBH, and PNMT compared with MN/NMN-secreting tumors. MN/NMN-secreting PPGLs had mainly KS alterations (52.1%), whereas NMN-only PPGLs had PH alterations (41.9%). PPGLs in the PH versus KS group had gene promoter hypermethylation of PAH (p = .002), DBH (p = .02), and PNMT (p = .003). CONCLUSIONS: Promoter methylation of genes encoding catecholamine synthesis enzymes is strongly and inversely correlated with MN/NMN patterns in PPGLs. KS and PH-related tumors have distinct methylation patterns. These results imply that methylation is a key regulatory mechanism of catecholamine synthesis in PPGLs.

HIF1A transcriptional regulation of COX4I2 impacts angiogenesis in pheochromocytoma.

BACKGROUND: Pheochromocytoma (PCC) is a rare neuroendocrine tumor. Angiogenesis is primary contributing factor for tumorigenesis. Cytochrome c oxidase 4I2 (COX4I2) has been confirmed to take part in the progression of cancer. Hypoxia-inducible factor 1A (HIF1A) is the main regulatory factor for the steady-state response of hypoxia, involved in metabolism and angiogenesis. In this study, we intended to explore the functions of COX4I2 in PCC and the effect mechanism between HIF1A and COX4I2. MATERIALS AND METHODS: The RNA-sequencing and immunohistochemistry tested COX4I2 expression in highly vascular PCC. Small interfering RNA (siRNA) was used to reduce the mRNA expression of COX4I2, and a small molecule inhibitor was utilized to reduce the protein expression of HIF1A. Culturing cells in 1% O2environment was performed to activate HIF1A. Western blot was applied to quantify the expression of target genes at the protein levels. The supernatant from PCC cells and fibroblasts acted as the conditioned medium. We conducted the tube formation and transwell assays in human vascular endothelial cells (HUVECs) to determine angiogenesis, the binding of COX4I2 promoter and HIF1A was evaluated by the dual luciferase reporter assay. RESULTS: COX4I2 had been rigorously shown to be overexpressed in highly vascular PCC. Knockdown of COX4I2 in PCC cells (MPC) did not significantly impact angiogenesis, while knockdown of COX4I2 in fibroblast (3T3) notably inhibited angiogenesis. RNA sequencing suggested that the expression of 11 vascular markers, such as CD34 and angiogenesis associated pathways in 3T3, decreased with knockdown of COX4I2. HIF1A had been shown to enhance the mRNA expression of COX4I2 through transcriptional regulation. Activation and inhibition of HIF1A resulted in upregulation and downregulation of COX4I2, respectively. The HIF1A inhibitor demonstrated a reduction in angiogenesis. CONCLUSION: COX4I2 is overexpressed in highly vascular PCC and contributes to angiogenesis in fibroblasts. Mechanistically, HIF1A transcriptional regulation enhances COX4I2 and its effects on angiogenesis in PCC. COX4I2 might serve as a vascular marker and represent a potential target for vascular therapy.

Preoperative prediction of metastatic pheochromocytoma and paraganglioma using clinical, genetic, and biochemical markers: A cohort study.

BACKGROUND: The prevalence of metastatic pheochromocytoma and paraganglioma (PPGL) is approximately 15%-20%. Although there are indicators to assess metastatic risks, none of them predict metastasis reliably. Therefore, we aimed to develop and validate a scoring system using clinical, genetic, and biochemical risk factors to preoperatively predict the metastatic risk of PPGL. METHODS: In the cross-sectional cohort (n = 180), clinical, genetic, and biochemical risk factors for metastasis were identified using multivariate logistic regression analysis, and a novel scoring system was developed. The scoring system was validated and compared with the age, size of tumor, extra-adrenal location, and secretory type (ASES) score in the longitudinal cohort (n = 114). RESULTS: In the cross-sectional cohort, pseudohypoxia group-related gene variants (SDHB, SDHD, or VHL), methoxytyramine >0.16 nmol/L, and tumor size >6.0 cm were independently associated with metastasis after multivariate logistic regression. Using them, the gene variant, methoxytyramine, and size of tumor (GMS) score were developed. In the longitudinal cohort, Harrell's concordance index of the GMS score (0.873, 95% confidence interval [CI]: 0.738-0.941) was higher than that of the ASES score (0.713, 95% CI: 0.567-0.814, p = 0.007). In the longitudinal cohort, a GMS score ≥2 was significantly associated with a higher risk of metastasis (hazard ratio = 25.07, 95% CI: 5.65-111.20). A GMS score ≥2 (p < 0.001), but not ASES score ≥2 (p = 0.090), was associated with shorter progression-free survival. CONCLUSION: The GMS scoring system, which integrates gene variant, methoxytyramine level, and tumor size, provides a valuable preoperative approach to assess metastatic risk in PPGL.

Evaluation of bone mineral density (BMD) and trabecular bone score (TBS) in pheochromocytoma and paraganglioma; a multi-centric case-control study from India.

Pheochromocytoma and paraganglioma (PPGL) have been associated with low bone mineral density (BMD) due to excess sympathetic system stimulation. Our study revealed low BMD and TBS (trabecular bone score) in cases compared to matched controls. Plasma-free nor-metanephrine and hypertension duration found to be most consistent predictive factors. PURPOSE: Pheochromocytoma and paraganglioma (PPGL) have been associated with low bone mineral density (BMD) and increased fracture risks. Sympathetic nervous system stimulation has been shown to increase bone resorption and decrease bone formation via ß2 receptors. Chronic inflammation and increased cytokine production add to more bone loss. TBS (trabecular bone score) is an established surrogate marker for bone histomorphometry. BMD and TBS data in pheochromocytoma and PPGL are scarce. The aim was to assess the BMD and TBS in pheochromocytoma and PPGL and look for clinical and biochemical predictors. METHODS: This case-control study had sample size of 58 (29 cases and controls each). BMI-, age-, and sex-matched controls were taken for comparison. Both cases and controls had undergone DXA scan and BMD {Z-scores and bone mineral concentration (BMC) in g/cm2} and TBS were analyzed. Detailed clinical histories and relevant biochemistry values were noted. RESULTS: The mean age of our case population was 29.5 ± 9.4 years with a mean age of HTN onset at 26.86 ± 6.6 years. Lumbar spine BMC (0.86 ± 0.14 vs 0.96 ± 0.15; p = 0.036), femoral neck Z-score (- 1.23 ± 1.07 vs - 0.75 ± 0.97; p = 0.003), and whole body BMC (0.91 ± 0.14 vs 1.07 ± 0.11; p = 0.000) were significantly low in cases compared to controls. Similarly, TBS was significantly lower in cases compared to controls (1.306 ± 0.113 vs 1.376 ± 0.083; p = 0.001). CONCLUSION: This study establishes both low bone mass and poor bone quality in an Indian pheochromocytoma and PPGL patient's cohort. Plasma-free nor-metanephrine and duration of hypertension were found to be most consistent predictive factors in multivariate regression analysis.

In-Hospital Adverse Events of Pheochromocytoma-Induced Takotsubo Syndrome: A Literature Review and Cluster Analysis of 172 Cases.

Background: Pheochromocytoma-induced takotsubo syndrome (Pheo-TTS) significantly increases the risk of adverse events for inpatient. The early identification of risk factors at admission is crucial for effective risk stratification and minimizing complications in Pheo-TTS patients. Methods: We conducted a systematic review combined with hierarchical cluster and feature importance analysis of demographic, clinical and laboratory data upon admission, alongside in-hospital complication data for Pheo-TTS patients. We analyzed cases published in PubMed and Embase from 2 May 2006 to 27 April 2023. Results: Among 172 Pheo-TTS patients, cluster analysis identified two distinct groups: a chest pain dominant (CPD) group (n = 86) and a non-chest pain dominant (non-CPD) group (n = 86). The non-CPD group was characterized by a younger age (44.0 ± 15.2 vs. 52.4 ± 14.4, p < 0.001), a higher prevalence of neurological/psychiatric disorders (53.5% vs. 32.6%), and increased presentation of dyspnea (87.2% vs. 17.4%), pulmonary rales (59.3% vs. 8.1%), and tachycardia (77.9% vs. 30.2%). Additionally, they exhibited more atypical takotsubo syndrome (TTS) imaging phenotypes (55.8% vs. 36.5%, all p < 0.05). The non-CPD group experienced more than a 2-fold increase for in-hospital adverse events compared to the CPD group (70.9% vs. 30.2%, p < 0.001). After adjusting for confounding factors, the absence of chest pain (odds ratio [OR] = 0.407, 95% confidence interval [CI] 0.169-0.979, p = 0.045), the presence of abdominal symptoms (OR = 3.939, 95% CI 1.770-8.766, p = 0.001), pulmonary rales (OR = 4.348, 95% CI 1.857-10.179, p = 0.001), and atypical TTS imaging phenotype (OR = 3.397, 95% CI 1.534-7.525, p = 0.003) remained as independent predictors of in-hospital complications. Conclusions: Clinical manifestations and imaging features at admission help to predict in-hospital complications for Pheo-TTS patients.

Head-to-head comparison between [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT in a diverse cohort of patients with pheochromocytomas and paragangliomas.

PURPOSE: To compare the detection ability of 68Ga-labelled DOTA-l-Nal3-octreotide ([68Ga]Ga-DOTA-NOC) and 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]DOPA) in patients with phaeochromocytomas and paragangliomas (PPGLs) of different origins and gene mutations, such as germline succinate dehydrogenase complex genes (SDHx). METHODS: Eighty-five patients with histopathologically confirmed PPGLs who underwent both [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT from March 2017 to June 2023 were enrolled in this retrospective study. For comparative analyses, PPGLs were classified as phaeochromocytoma (PCC), sympathetic paraganglioma (sPGL), and head/neck paraganglioma (HNPGL). Detection rates were analyzed on per-patient and per-lesion bases and compared using the Chi-square/Fischer's exact test. RESULTS: Among 85 patients with PPGLs (48 males; 43 years ± 17 [SD]), the patient-based detection rates of [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT were 87.1% (74/85) and 89.4% (76/85), respectively (p = 0.634), and the lesion-based detection rates were 80.8% (479/593) and 71.2% (422/593), respectively (p < 0.001). Only one patient with a recurrent PCC presented double-negative imaging, while 66 patients exhibited double-positive imaging. The remaining patients were either [68Ga]Ga-DOTA-NOC-negative/[18F]DOPA-positive (n = 10) or [68Ga]Ga-DOTA-NOC-positive/[18F]DOPA-negative (n = 8). In subgroup analyses, [68Ga]Ga-DOTA-NOC PET/CT detected significantly more metastases of sPGL (91.1%, 236/259) and SDHx-related PPGL (89.6%, 86/96) than [18F]DOPA PET/CT (48.6%[126/259] and 50.0%[48/96], respectively; both p < 0.001). However, [18F]DOPA showed significantly higher detection rates of PCC in both primary/recurrent and metastatic lesions (94.3%[50/53] vs. 62.3%[33/53] and 87.9%[174/198] vs. 69.2%[137/198], respectively; both p < 0.001). Regarding metastases in different organs, [68Ga]Ga-DOTA-NOC PET/CT detected more lesions than [18F]DOPA PET/CT in bone (96.2%[176/183] vs. 66.1%[121/183]; p < 0.001) and lymph nodes (82.0%[73/89] vs. 53.9%[48/89]; p < 0.001) but less lesions in peritoneum (20%[4/20] vs. 100%[20/20]; p < 0.001). CONCLUSION: [68Ga]Ga-DOTA-NOC and [18F]DOPA are complementary in diagnosing PPGL under the appropriate clinical setting. [68Ga]Ga-DOTA-NOC should be considered as the ideal first-line tracer for detecting metastases of sPGL and SDHx-related tumours, whereas [18F]DOPA may be the optimal tracer for evaluating non-SDHx-related PCC, especially in detecting primary lesions and monitoring recurrence.

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.

Clinical Significance of Pheochromocytoma Size on the Timing and Extent of Surgery.

INTRODUCTION: Elevated metanephrine and catecholamine levels 3-fold upper limit of normal (ULN) are diagnostic for pheochromocytoma. We sought to determine whether size correlates with biochemical activity or symptoms which could guide timing of surgery. METHODS: Data from consecutive patients undergoing adrenalectomy for pheochromocytoma at our institution over a 10-year period were retrospectively collected. These included maximal lesion diameter on preoperative imaging, plasma/urine metanephrine and/or catecholamine levels, demographic variables and presence of typical paroxysmal symptoms. Receiver operating characteristic curves were used to assess predictive accuracy. RESULTS: Sixty-three patients were included in the analysis (41 females and 22 males). Median age was 56 (43, 69) years. Due to various referring practices, 31 patients had documented 24-h urine metanephrine, 26 had 24-h urine catecholamine, and 52 had fractionated plasma metanephrine levels available for review. Values were converted to fold change compared to ULN and the maximum of all measured values was used for logistic regression. Median tumor size was 3.40 (2.25, 4.55) cm in greatest dimension. Tumor size at which pheochromocytoma produced > 3-fold ULN was ≥2.3 cm (AUC of 0.84). Biochemical activity increased with doubling tumor size (odds ratio = 8, P = 0.0004) or ≥ 1 cm increase in tumor size (odds ratio = 3.03, P = 0.001). 40 patients had paroxysmal symptoms, but there was no significant correlation between tumor size/biochemical activity and symptoms. CONCLUSIONS: In our study, tumor size directly correlated with the degree of biochemical activity and pheochromocytomas ≥2.3 cm produced levels 3 times ULN. These findings may allow clinicians to adjust timing of operative intervention.

Adrenalectomy Outcome Variations Across Different Functional Adrenal Tumors.

INTRODUCTION: Adrenalectomy generally has favorable outcomes. It is unknown if patients with functional adrenal tumors experience different clinical outcomes than those with benign adrenal tumors, due to the presence of comorbid conditions secondary to the functional tumor. We investigated outcomes following open and laparoscopic adrenalectomy for benign nonfunctional (BNF) versus functional adrenal masses. METHODS: Patients undergoing adrenalectomy were identified in the 2015-2020 National Surgical Quality Improvement Program database, then categorized as BNF, hyperaldosteronism, hypercortisolism, and pheochromocytoma. The primary outcome of interest was 30-d morbidity and secondary outcomes included 30-d mortality, 30-d readmission, and postoperative length of stay (LOS). Subgroup analysis was performed based upon surgical approach. Univariate analysis was performed, followed by multivariable logistic regression for individual outcomes that differed significantly between patients with BNF and functional neoplasm, factoring in patient demographics and operative approach with statistical significance on univariate analysis. Descriptive statistics and outcomes were analyzed using Pearson's χ2 test and Mann-Whitney U-test as appropriate. RESULTS: There were 3291 patients with BNF while 484 had hyperaldosteronism, 263 hypercortisolism, and 46 pheochromocytomas. Within the laparoscopic group of 3615 (88.5%) of adrenalectomy patients, compared to BNF patients, patients with hyperaldosteronism had lower rates of postoperative morbidity (1.9% versus 5.2%, P < 0.001) and shorter LOS (1 d, interquartile range (IQR) [1-1] versus 1d IQR [1-2], P = 0.003); these persisted on multivariate analysis (OR 0.32, 95% confidence interval [CI] 0.14-0.74 and odds ratio 0.47, 95% CI 0.36-0.60, P < 0.001). Patients with hypercortisolism had higher morbidity (7.3% versus 5.2%, P < 0.001), 30-d readmission rates (5.3% versus 2.9%, P = 0.042) and longer LOS (2d, IQR [1-3] versus 1d, IQR [1-2, P < 0.001). On multivariate analysis, presence of hypercortisolism was independently associated with increased likelihood of readmission within 30 d (OR 2.20, 95% CI 1.11-2.99, P = 0.012) and longer LOS (>1 d) (OR 1.79, 95% CI 1.33-2.40, P < 0.001). Compared to BNF patients, patients with pheochromocytoma had higher rates of postoperative morbidity (6.2% versus 5.2%, P < 0.001). Within the open group of 469 (11.5% of adrenalectomy patients), there were no statistically significant differences in outcomes between patients with BNF and functional adrenal masses. CONCLUSIONS: Outcomes after adrenalectomy performed for functional neoplasms differ based on surgical indication.

Prediction model for pheochromocytoma/paraganglioma using nCounter assay.

BACKGROUND: World Health Organization defined pheochromocytomas/paragangliomas (PPGL) as malignant tumors in 2017 because the existing classification system could not reflect locally aggressive behavior sufficiently. However, predicting the likelihood of metastasis remains a crucial part of the treatment strategy. METHODS: From one tertiary care hospital and one secondary hospital, 97 PPGL cases were selected. Medical records of PPGL cases with the presence of formalin-fixed and paraffin-embedded (FFPE) tissue of primary lesion were reviewed. For FFPE tissues, a nCounter assay was conducted to determine differently expressed genes between metastatic and non-metastatic PPGL groups. Performances of prediction models for the likelihood of metastasis were calculated. RESULTS: Of a total of 97 PPGL cases, 39, 20, and 38 were classified as benign, malignant, and validation, respectively. In the nCounter assay, CDK1, TYMS, and TOP2A genes showed significant differences in expression. Tumor size was positively correlated with CDK1 expression level. The Lasso regression model showed supreme performance of sensitivity 91.7% and specificity 95.5% when those significant factors were considered. CONCLUSION: Machine learning of multi-modal classifiers can be used to create a prediction model for metastasis of PPGL with high sensitivity and specificity using nCounter assay. Moreover, CDK1 inhibitors could be considered for developing drug treatment.

Identification of risk factors for postoperative persistent hypertension in patients with pheochromocytoma.

BACKGROUND: Surgical resection is the primary management for pheochromocytoma. However, some patients with pheochromocytoma still suffer from hypertension after successful adrenalectomy. The risk factors for postoperative persistent hypertension remain unclear. Thus the aim of the present study was to identify the risk factors of postoperative persistent hypertension in patients with pheochromocytoma concomitant with hypertension. METHODS: We retrospectively analyzed 259 patients with pheochromocytoma who underwent adrenalectomy in our hospital between January 1, 2007, and December 31, 2018. Patients' demographics, comorbidities, and perioperative data were recorded. The odds ratio (OR) and 95% confidence interval were measured through binary logistic regression. The cutoff values and the area under the curve (AUC) for continuous risk factors of persistent hypertension after adrenalectomy were calculated through receiver operating characteristic curve analysis. RESULTS: Of the 259 patients, 40.9% (106/259) patients experienced postoperative persistent hypertension. Three independent risk factors of persistent hypertension in patients with pheochromocytoma after adrenalectomy were found to be older age (OR = 1.16, p = 0.037), longer duration of hypertension (OR = 3.10, p = 0.01), and concomitance with cardiovascular events (yes vs. no, OR = 17.17, p = 0.049). The cutoff value of age and duration of hypertension was 66 years (AUC = 0.741, p < 0.0001) and 27 months (AUC = 0.991, p < 0.0001), respectively. CONCLUSIONS: Collectively, older age, a longer duration of hypertension, and concomitance with cardiovascular events were independent risk factors of persistent hypertension in patients with pheochromocytoma after adrenalectomy. These findings may help in improving perioperative management and follow-up strategies.

Adolescent- and adult-onset neuroblastic tumor: A retrospective multicenter observational study of patients diagnosed in France between 2000 and 2020.

BACKGROUND: Adult- and adolescent-onset neuroblastomas are rare, with no established therapy. In addition, rare pheochromocytomas may harbor neuroblastic components. This study was designed to collect epidemiological, diagnostic and therapeutic data in order to better define the characteristics of malignant peripheral neuroblastic tumors (MPNT) and composite pheochromocytomas (CP) with MPNT. PROCEDURE: Fifty-nine adults and adolescents (aged over 15 years) diagnosed with a peripheral or composite neuroblastic tumor, who were treated in one of 17 institutions between 2000 and 2020, were retrospectively studied. RESULTS: Eighteen patients with neuroblastoma (NB) or ganglioneuroblastoma (GNB) had locoregional disease, and 28 patients had metastatic stage 4 NB. Among the 13 patients with CP, 12 had locoregional disease. Fifty-eight percent of the population were adolescents and young adults under 24 years of age. The probability of 5-year event-free survival (EFS) was 40% (confidence interval: 27%-53%). CONCLUSIONS: Outcomes were better for patients with localized tumor than for patients with metastases. For patients with localized tumor, in terms of survival, surgical treatment was the best therapeutic option. Multimodal treatment with chemotherapy, surgery, radiotherapy, and immunotherapy-based maintenance allowed long-term survival for some patients. Adolescent- and adult-onset neuroblastoma appeared to have specific characteristics associated with poorer outcomes compared to pediatric neuroblastoma. Nevertheless, complete disease control improved survival. The presence of a neuroblastic component in pheochromocytoma should be considered when making therapeutic management decisions. The development of specific tools/resources (Tumor Referral Board, Registry, biology, and trials with new agents or strategies) may help to improve outcomes for patients.

Pseudohypoxia in paraganglioma and pheochromocytoma is associated with an immunosuppressive phenotype.

Metastatic pheochromocytoma and paraganglioma (PPGL) have poor prognosis and limited therapeutic options. The recent advent of immunotherapies showing remarkable clinical efficacies against various cancer types offers the possibility of novel opportunities also for metastatic PPGL. Most PPGLs are pathogenically linked to inactivating mutations in genes encoding different succinate dehydrogenase (SDH) subunits. This causes activation of the hypoxia-inducible factor 2 (HIF2)-mediated transcriptional program in the absence of decreased intratumoral oxygen levels, a phenomenon known as pseudohypoxia. Genuine hypoxia in a tumor creates an immunosuppressive tumor microenvironment. However, the impact of pseudohypoxia in the immune landscape of tumors remains largely unexplored. In this study, tumoral expression of programmed death-ligand 1 (PD-L1) and HIF2α and tumor infiltration of CD8 T lymphocytes (CTLs) were examined in PPGL specimens from 102 patients. We assessed associations between PD-L1, CTL infiltration, HIF2α expression, and the mutational status of SDH genes. Our results show that high PD-L1 expression levels in tumor cells and CTL tumor infiltration were more frequent in metastatic than nonmetastatic PPGL. However, this phenotype was negatively associated with SDH mutations and high HIF2α protein expression. These data were validated by analysis of mRNA levels of genes expressing PD-L1, CD8, and HIF2α in PPGL included in The Cancer Genome Atlas database. Further, PD-L1 and CD8 expression was lower in norepinephrine than epinephrine-secreting PPGL. This in silico analysis also revealed the low PD-L1 or CD8 expression levels in tumors with inactivating mutations in VHL or activating mutations in the HIF2α-coding gene, EPAS1, which, together with SDH-mutated tumors, comprise the pseudohypoxic molecular subtype of PPGL. These findings suggest that pseudohypoxic tumor cells induce extrinsic signaling toward the immune cells promoting the development of an immunosuppressive environment. It also provides compelling support to explore the differential response of metastatic PPGL to immune checkpoint inhibitors. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

A rare case of pheochromocytoma in a pregnant woman presenting with chest pain: extraordinary management.

BACKGROUND: Pheochromocytoma is rare in pregnant women. It presents as diverse symptoms, including hypertension and sweating. The symptoms of pregnant women with pheochromocytoma and comorbid hypertension often mimic the clinical manifestations of preeclampsia, and these women are often misdiagnosed with preeclampsia. CASE PRESENTATION: In this case, a pregnant woman presented with chest pain as the primary symptom, and a diagnosis of pheochromocytoma was considered after ruling out myocardial ischemia and aortic dissection with the relevant diagnostic tools. This patient then underwent successful surgical resection using a nontraditional management approach, which resulted in a positive clinical outcome. CONCLUSIONS: It is essential to consider pheochromocytoma as a potential cause of chest pain and myocardial infarction-like electrocardiographic changes in pregnant women, even if they do not have a history of hypertension.

Hypertension and cardiac damage in pheochromocytoma and paraganglioma patients: a large-scale single-center cohort study.

BACKGROUND: Hypertension (HT) is one of the most common manifestations in patients with catecholamine-secreting neuroendocrine tumors. Although the cardiovascular manifestations of these tumors have been described, there have been no large-scale investigations of the profile of HT and changes in cardiac structure and function that occur in patients with pheochromocytomas and paragangliomas (PPGL). MATERIALS AND METHODS: In this study, we investigated the prevalence of HT and left ventricular remodeling (LVR) in a cohort of 598 patients who underwent surgery for PPGL at our center between January 2001 and April 2022. Information on demographics, reason for hospitalization, medical history, biochemical parameters, findings on echocardiography, and tumor characteristics were recorded. The LVR index was compared according to whether or not there was a history of HT. RESULTS: The average age was 47.07 ± 15.07 years, and 277 (46.32%) of the patients were male. A history of HT was found in 423 (70.74%) of the 598 patients. Paraganglioma was significantly more common in the group with HT (26.00% vs. 17.71%, P = 0.030) and significantly less likely to be found incidentally during a health check-up in this group (22.93% vs. 59.43%, P < 0.001). Among 365 patients with complete echocardiography data, left ventricular mass index (86.58 ± 26.70 vs. 75.80 ± 17.26, P < 0.001) and relative wall thickness (0.43 ± 0. 08 vs. 0.41 ± 0.06, P = 0.012) were significantly higher in patients with PPGL and a history of HT. The proportions with left ventricular hypertrophy (LVH) (19.40% vs. 8.25%, P = 0.011) and LVR (53.73% vs. 39.18%, P = 0.014) were also higher when there was a history of HT. After adjusting for age, gender, body mass index, alcohol consumption, smoking status, diabetes, stroke, creatinine level, tumor location, and tumor size, a history of HT was significantly correlated with LVH (odds ratio 2.71, 95% confidence interval 1.18-6.19; P = 0.018) and LVR (odds ratio 1.83, 95% confidence interval 1.11-3.03; P = 0.018). CONCLUSION: HT is common in patients with PPGL (70.74% in this cohort). PPGL without a history of HT is more likely to be found incidentally (59.43% in our cohort). HT is associated with LVR in PPGL patients with complete echocardiography data. These patients should be observed carefully for cardiac damage, especially those with a history of HT.

Side-specific factors for intraoperative hemodynamic instability in laparoscopic adrenalectomy for pheochromocytoma: a comparative study.

BACKGROUND: Adrenalectomy for pheochromocytoma (PHEO) is challenging because of the high risk of intraoperative hemodynamic instability (HDI). This study aimed to compare the incidence and risk factors of intraoperative HDI between laparoscopic left adrenalectomy (LLA) and laparoscopic right adrenalectomy (LRA). METHODS: We retrospectively analyzed two hundred and seventy-one patients aged > 18 years with unilateral benign PHEO of any size who underwent transperitoneal laparoscopic adrenalectomy at our hospitals between September 2016 and September 2023. Patients were divided into LRA (N = 122) and LLA (N = 149) groups. Univariate and multivariate logistic regression analyses were used to predict intraoperative HDI. In multivariate analysis for the prediction of HDI, right-sided PHEO, PHEO size, preoperative comorbidities, and preoperative systolic blood pressure were included. RESULTS: Intraoperative HDI was significantly higher in the LRA group than in the LLA (27% vs. 9.4%, p < 0.001). In the multivariate regression analysis, right-sided tumours showed a higher risk of intraoperative HDI (odds ratio [OR] 5.625, 95% confidence interval [CI], 1.147-27.577, p = 0.033). The tumor size (OR 11.019, 95% CI 3.996-30.38, p < 0.001), presence of preoperative comorbidities [diabetes mellitus, hypertension, and coronary heart disease] (OR 7.918, 95% CI 1.323-47.412, p = 0.023), and preoperative systolic blood pressure (OR 1.265, 95% CI 1.07-1.495, p = 0.006) were associated with a higher risk of HDI in both LRA and LLA, with no superiority of one side over the other. CONCLUSION: LRA was associated with a significantly higher intraoperative HDI than LLA. Right-sided PHEO was a risk factor for intraoperative HDI.

Deteriorated bone microarchitecture caused by sympathetic overstimulation in pheochromocytoma and paraganglioma.

PURPOSE: Despite the potentially destructive effect of sympathetic activity on bone metabolism, its impact on bone microarchitecture, a key determinant of bone quality, has not been thoroughly investigated. This study aims to evaluate the impact of sympathetic activity on bone microarchitecture and bone strength in patients with pheochromocytoma and paraganglioma (PPGL). METHODS: A cross-sectional study was conducted in 38 PPGL patients (15 males and 23 females). Bone turnover markers serum procollagen type 1 N-terminal propeptide (P1NP) and ß-carboxy-terminal crosslinked telopeptide of type 1 collagen (ß-CTX) were measured. 24-h urinary adrenaline (24hUE) and 24-h urinary norepinephrine levels (24hUNE) were measured to indicate sympathetic activity. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in PPGL patients and 76 age-, sex-matched healthy controls (30 males and 46 females). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously. RESULTS: PPGL patients had a higher level of ß-CTX. HR-pQCT assessment revealed that PPGL patients had notably thinner and more sparse trabecular bone (decreased trabecular number and thickness with increased trabecular separation), significantly decreased volume BMD (vBMD), and bone strength at both the radius and tibia compared with healthy controls. The deterioration of Tt.vBMD, Tb.Sp, and Tb.1/N.SD was more pronounced in postmenopausal patients compared with the premenopausal subjects. Moreover, subjects in the highest 24hUNE quartile (Q4) showed markedly lower Tb.N and higher Tb.Sp and Tb.1/N.SD at the tibia than those in the lowest quartile (Q1). Age-related bone loss was also exacerbated in PPGL patients to a certain extent. CONCLUSIONS: PPGL patients had significantly deteriorated bone microarchitecture and strength, especially in the trabecular bone, with an increased bone resorption rate. Our findings provide clinical evidence that sympathetic overstimulation may serve as a secondary cause of osteoporosis, especially in subjects with increased sympathetic activity.

A novel strategy for predicting the efficacy of temozolomide treatment for metastatic pheochromocytomas/paragangliomas.

BACKGROUND: There are few studies on the efficacy of temozolomide (TMZ) in the treatment of Metastatic pheochromocytoma / paraganglioma (MPP) patients. And it remains unclear which MPP patients may benefit from TMZ treatment. METHODS: This was a prospective study. MPP patients were enrolled. Patients were treated with TMZ until disease progression or intolerable toxicities. The primary endpoints were disease control rate (DCR) and objective response rate (ORR). Secondary endpoints included biochemical response rate progression-free survival (PFS) and safety. We compared the difference between effective and ineffective groups, to explore which patients are more suitable for TMZ treatment. RESULTS: 62 patients with MPP were enrolled and tumor response were evaluated in 54 patients. The DCR was 83% (35/42), and the ORR was 24% (10/41) among the progressive patients. PFS was 25.2 ± 3.1 months. The most common adverse event was nausea (41/55). We found that 92.9% (13/14) of patients with MGMT methylation greater than 7% respond to treatment. For the patients with MGMT methylation less than 7%, Ki-67 index could be used to guide the use of TMZ in these patients. Among the patients with Ki-67 index less than 5%, 66% (8/12) patients showed respond to treatment, and only 33% (4/12) patients with Ki-67 index more than 5% showed respond to TMZ. CONCLUSIONS: This study indicated that TMZ is a potential choice for the treatment of MPP with the high ability on disease control and well tolerability. We recommended to MGMT methylation analysis test and Ki-67 index to guide TMZ application.

Impact of Pheochromocytoma or Paraganglioma on Bone Metabolism: A Systemic Review and Meta-analysis.

INTRODUCTION: Preclinical and animal studies have suggested that excess catecholamines can lead to bone mineral loss. However, to date, no systematic review is available that has analyzed the impact of catecholamine excess in the context of pheochromocytoma/paraganglioma (PPGL) on bone metabolism. We conducted this meta-analysis to address this knowledge gap. METHODS: Electronic databases were searched for studies evaluating bone metabolism, including assessments of bone mineral density (BMD), quantitative computed tomography (qCT), trabecular bone score (TBS), or bone turnover markers in patients with PPGL. These markers included those of bone resorption, such as tartrate-resistant acid phosphatase 5b (TRACP-5b) and cross-linked C-telopeptide of type I collagen (CTx), as well as markers of bone formation, such as bone-specific alkaline phosphatase (BS ALP). RESULTS: Out of the initially screened 1614 articles, data from six studies published in four different patient cohorts with PPGL that met all criteria were analysed. Individuals with PPGL had significantly lower TBS [Mean Difference (MD) -0.04 (95% CI: -0.05--0.03); p < 0.00001; I2 = 0%], higher serum CTx [MD 0.13 ng/ml (95% CI: 0.08-0.17); p < 0.00001; I2 = 0%], and higher BS-ALP [MD 1.47 U/L (95% CI: 0.30-2.64); p = 0.01; I2 = 1%]. TBS at 4-7 months post-surgery was significantly higher compared to baseline [MD 0.05 (95% CI: 0.02-0.07); p < 0.0001]. A decrease in CTx has been documented post-surgery. CONCLUSION: Bone health deterioration is a major concern in patients with PPGL. In addition to providing a definitive cure for catecholamine excess, monitoring and treating osteoporosis is essential for individuals with secondary osteoporosis due to PPGL. Long-term studies on bone health outcomes in PPGL are warranted.