Efficacy and Safety of Tyrosine Kinase Inhibitors in Patients with Metastatic Pheochromocytomas/Paragangliomas.

CONTEXT: Tyrosine kinase inhibitors (TKIs) can be used to treat locally unresectable or distantly metastatic pheochromocytomas/paragangliomas (PPGLs), such as sunitinib, according to the National Comprehensive Cancer Network guidelines in 2022. However, the precise effect of different TKIs in metastatic PPGLs is still unclear. OBJECTIVE: The aim of this meta-analysis is to assess the efficacy and safety of TKIs in metastatic PPGLs. METHODS: The PubMed, Cochrane Library, Scopus, Clinical Trial, and Embase databases were searched by synonyms of 48 TKIs and metastatic PPGLs from inception up to August 2022. Outcomes were tumor response or survival data and the incidence of adverse events (AEs) after treatment. The MIONRS scale and the JBI's tools for case series were used for interventional and observational studies to assess risk of bias, respectively. The combined effects with fixed- or random-effect models, the combined median with the weighted median of medians method and their 95% CIs were reported. RESULTS: A total of 7 studies with 160 patients were included. Tumor responses in metastatic PPGLs in 5 studies with available data showed the pooled proportion of partial response (PR), stable disease, and disease control rate (DCR) of, respectively, 0.320 (95% CI 0.155-0.486), 0.520 (95% CI 0.409-0.630), and 0.856 (95% CI 0.734-0.979). The combined median progressive-free survival in 6 studies was 8.9 months (95% CI 4.1-13.5) and the proportion of those who discontinued due to AEs in 5 studies was 0.143 (95% CI 0.077-0.209). CONCLUSION: This meta-analysis suggests that patients with metastatic PPGLs can benefit from TKI therapy with PR and DCR up to more than 30% and 80%. However, because of restricted studies, larger clinical trials should be performed in the future.

Functional nodules in primary aldosteronism: identification of CXCR4 expression with 68Ga-pentixafor PET/CT.

OBJECTIVES: We analyzed the diagnostic efficiency of 68Ga-pentixafor PET/CT for functional nodules in primary aldosteronism (PA). Furthermore, we compared the correlation of CXCR4 expression with aldosterone synthase (CYP11B2) expression and PET/CT uptake in these patients. METHODS: We prospectively assessed 50 patients diagnosed with PA and 10 patients with non-functional adrenal adenoma (NFA). All patients underwent 68Ga-pentixafor PET/CT before adrenalectomy. Immunohistochemistry (IHC) was performed to detect the protein expression of CYP11B2 and the G-protein-coupled receptor CXCR4. RESULTS: CYP11B2 IHC revealed the presence of 43 functional nodules. Subsequently, 40/43 functional nodules could be detected on 68Ga-pentixafor PET/CT, while negative imaging findings were noted for 11/13 non-functional nodules (sensitivity, 93.0%; specificity, 84.6%). The optimum SUVmax cut-off for the identification of functional nodules was 8.95 (AUC 0.914 [0.828-1.000], p < 0.001). Regarding the size of functional nodules, diagnostic efficiency appeared to be much higher for nodules greater than 1 cm in size (sensitivity, up to 97.3%). Moreover, we examined the relationship between CXCR4 and CYP11B2 expression in 56 lesions. All 43 CYP11B2-positive nodules were CXCR4-positive, but one of the 13 CYP11B2-negative nodules (7.7%) showed false-positive staining for CXCR4. Moreover, the consistency between PET/CT uptake and CXCR4 staining results was 92.9% (52/56). CONCLUSIONS: At least 90% of functional nodules show positive uptake on 68Ga-pentixafor PET/CT, and the detection ability is much better for nodules with a diameter ≥ 1 cm. With its high sensitivity and specificity, 68Ga-pentixafor PET/CT can be considered a promising surgical decision-making tool for patients with PA. KEY POINTS: • 68Ga-pentixafor PET/CT could be a useful tool for the identification of functional adrenal nodules in APAs and even IHAs. • The diagnostic efficiency appears to be much higher for nodules ≥ 1 cm in size. • There is high consistency between the results of 68Ga-pentixafor PET/CT imaging and CXCR4 immunohistochemistry.

Development and internal validation of a novel predictive model for SDHB mutations in pheochromocytomas and retroperitoneal paragangliomas.

Aim: To develop and internally validate a novel predictive model for SDHB mutations in pheochromocytomas and retroperitoneal paragangliomas (PPGLs). Methods: Clinical data of patients with PPGLs who presented to Peking Union Medical College Hospital from 2013 to 2022 and underwent genetic testing were retrospectively collected. Variables were screened by backward stepwise and clinical significance and were used to construct multivariable logistic models in 50 newly generated datasets after the multiple imputation. Bootstrapping was used for internal validation. A corresponding nomogram was generated based on the model. Sensitivity analyses were also performed. Results: A total of 556 patients with PPGLs were included, of which 99 had a germline SDHB mutation. The prediction model revealed that younger age of onset [Odds ratio (OR): 0.93, 95% CI: 0.91-0.95], synchronous metastasis (OR: 6.43, 95% CI: 2.62-15.80), multiple lesion (OR: 0.22, 95% CI: 0.09-0.54), retroperitoneal origin (OR: 5.72, 95% CI: 3.13-10.47), negative 131I-meta-iodobenzylguanidine (MIBG) (OR: 0.34, 95% CI: 0.15-0.73), positive octreotide scintigraphy (OR: 3.24, 95% CI: 1.25-8.43), elevated 24h urinary dopamine (DA) (OR: 1.72, 95% CI: 0.93-3.17), NE secretory type (OR: 2.83, 95% CI: 1.22- 6.59), normal secretory function (OR: 3.04, 95% CI: 1.04-8.85) and larger tumor size (OR: 1.09, 95% CI: 0.99-1.20) were predictors of SDHB mutations in PPGLs, and showed good and stable predictive performance with a mean area under the ROC curve (AUC) of 0.865 and coefficient of variation of 2.2%. Conclusions: This study provided a novel and useful tool for predicting SDHB mutations by integrating easily obtained clinical data. It may help clinicians select suitable genetic testing methods and make appropriate clinical decisions for these high-risk patients.

Case report: Antiplatelet therapy on metastatic paraganglioma-associated cutaneous vascular disease and literature review.

Context: Tumor-associated cutaneous vascular disorder induced by PPGL was extremely rare, and the cutaneous manifestations could disappear after removal of the tumors. However, the definite pathological diagnosis and the potential mechanism remained unidentified. We presented a severe cutaneous vascular lesion manifested as diffuse erythema with ulceration and necrosis over the limbs in a female patient with metastatic paraganglioma. Skin biopsy was performed on her for defining the pathological diagnosis and potential mechanism. The patient was diagnosed as vascular disease according to the obvious angioectasia in dermis on cutaneous pathology, which might be caused by PPGL-induced hypercoagulability. We used the antiplatelet therapy with aspirin to treat the PPGL-associated cutaneous vascular disease for the first time, and the cutaneous lesions were relieved and healed gradually, further supporting the diagnosis of vascular disease. Conclusion: For metastatic PPGL patients like the case we reported, the definite diagnosis by skin biopsy and the early antiplatelet therapy might be effective to the cutaneous lesions caused by the hypercoagulable state of PPGL.

Mutational Profile and Potential Molecular Therapeutic Targets of Pheochromocytoma.

Purpose: Pheochromocytoma/paraganglioma (PCC/PGL; collectively known as PPGL) can be driven by germline and somatic mutations in susceptibility genes. We aimed to investigate the mutation profile and clinical features of pathogenic genes in highly genetically heterogeneous PPGL and to preliminary explore molecular therapeutic targets in PPGL. Methods: We established a panel of 260 genes, including susceptibility genes of PPGL and other important tumorigenic genes to sequence 107 PPGL tissues. Results: Overall, 608 genomic mutations were identified in 107 PPGL tissues. Almost 57% of PPGL tissue samples exhibited pathogenic mutations, and the most frequently mutated gene was SDHB (15/107, 14%). SDHB and HRAS were the most commonly mutated genes in germline-mutated PPGL (25/107, 23%) and nongermline-mutated PPGL (36/107, 34%), respectively. In addition, novel pathogenic mutations were detected in sporadic PPGL. PPGL with mutations in the hypoxia pathway had an earlier onset and higher norepinephrine level than those in the kinase pathway. Receptor tyrosine kinase (RTK; 22%, 24/107), mitogen-activated protein kinase (MAPK; 14%, 15/107), and tyrosine kinase (TK; 2%, 2/107) pathways were the most frequently mutated pathways in PPGL. Conclusion: Our results provided the genetic mutation profile in PPGL tissues. Genetic mutations in PPGL were mainly concentrated in the RTK, TK, and MAPK pathways, suggesting potential molecular therapeutic targets for PPGL.

Fumarate hydratase gene germline variants and mosaicism associated with pheochromocytoma and paraganglioma.

Fumarate hydratase (FH) catalyzes the conversion of fumaric acid to L-malic acid. Heterozygous variants of the human fumarate hydratase gene (FH) predispose to hereditary leiomyomatosis and renal cell cancer and, rarely, pheochromocytoma/paraganglioma (PPGL). No mosaic variant in FH has been reported yet. Using next-generation sequencing, five individuals with FH variants were found in 319 PPGL patients. Immunohistochemistry staining and loss of heterozygosity analysis in tumor tissues were performed to determine the pathogenicity of the variants. Deep targeted sequencing was performed on the peripheral blood DNA of a pheochromocytoma (PCC) patient with uterine leiomyomas. Finally, two of the five variants were found to be pathogenic. A germline variant (c.817G>A, p.Ala273Thr) was found in a patient with a PPGL family history. A mosaic variant (c.206G>A, p.Gly69Asp) with an allelic ratio of 5% in blood DNA was confirmed in the PCC patient with uterine leiomyomas. No metastatic PPGL was observed in the two PPGL patients with FH pathogenic variants. In summary, we report mosaicism in FH and the first PPGL pedigree with an FH pathogenic germline variant. Both germline variants and mosaicism should be taken into account during genetic testing.

Convergence between germline and somatic mutations in pancreatic neuroendocrine tumors.

Objectives: The pancreatic neuroendocrine tumors (PanNETs) are a group of clinically heterogeneous neoplasms. Although previous studies illustrated the somatic mutation pattern for PanNETs, the germline mutation pattern is still unclear. Here, we comprehensively screened the underlying germline mutations in a cohort of multiple endocrine neoplasia type 1 (MEN1)-related and sporadic PanNETs to reveal the characteristics of germline mutation in PanNET patients. Methods: Patients diagnosed with PanNETs by biopsy or surgical pathology were enrolled in this study. Peripheral blood samples were used for genomic DNA purification and subsequent sequencing. The following sequencing techniques were used and compared for validation: (1) targeted gene capture with a customized panel; (2) whole exome sequencing data from previous study. Results: A total of 184 PanNET patients were enrolled, including 20 MEN1-related and 164 sporadic cases. In this study, MEN1 mutation rate in MEN1-related PanNETs was 60% (12/20), of which 50% were novel mutation sites. For sporadic PanNETs, the overall germline mutation rate was very low. Besides the rare MEN1 mutation, previously unreported germline variant in DAXX was found in one non-functional PanNET. Conclusions: This study revealed distinctive germline mutation rates between MEN1-related and sporadic PanNETs. The novel MEN1 mutations contribute to revealing the spectrum of MEN1 mutations in PanNETs. The newly discovered germline variant of DAXX in sporadic PanNET implies a tendency of convergence between germline and somatic mutation genes.

Local-Regional Recurrence of Pheochromocytoma/Paraganglioma: Characteristics, Risk Factors and Outcomes.

Objective: To study the characteristics, risk factors, and outcomes of local-regional recurrence of pheochromocytoma and paraganglioma (PPGL). Methods: Clinical data of 96 PPGL patients with local-regional recurrence and 112 patients without recurrence were retrospectively analyzed. Results: Recurrent patients exhibited a median recurrence time of 6.0 (4.0, 9.0) years after resection of the primary tumor. SDHB mutation [HR 4.1 (1.7, 9.5), p=0.001), primary tumor size ≥5cm [HR 2.3 (1.1, 4.7), p=0.028], and average Ki-67 count ≥3% in the primary tumor [HR 2.6 (1.4, 4.9), p=0.003] were independent predictors for recurrence of PPGL. Primary tumor sizes ≥5cm [HR 5.1 (1.7, 15.3), p=0.003] and average Ki-67 counts ≥3% of the primary tumor [HR 2.4 (1.1, 5.2), p=0.035] were independent predictors for recurrence of pheochromocytoma, while SDHB mutation [HR 4.6 (1.5, 13.9), p=0.007] was a predictor for paraganglioma recurrence. Among recurrent patients, 47% (45/96) had multiple nodules in recurrent sites, and 58% (56/96) had metastases, with 20% (19/96) being implantation metastases. The risk of metastases (42% vs. 25%, p=0.030) and death (15% vs. 8%, p=0.003) was significantly increased in untreated patients after recurrence compared with treated patients. Conclusion: Long-term follow-up is necessary for all PPGL patients. Risk factors for recurrence of pheochromocytoma and paraganglioma differ, with primary tumor size and average Ki-67 count representing independent predictors for pheochromocytoma patients and SDHB mutations predicting paraganglioma recurrence. Although the treatment of recurrence can be difficult, patients should be treated once recurrence is detected as it decreases the risk of metastases and death.

The Bioinformatics Analysis of Aldosterone-Producing Adenoma and Verification of Differentially Expressed Genes.

PURPOSE: Previous studies have investigated the transcriptional modulations of aldosterone overproduction of aldosterone-producing adenomas (APAs). We aimed to systematically study the genes and pathways associated with molecular mechanism underlying APA by bioinformatics analysis and experimental validation for the expression profile. METHODS: This study was performed based on three gene expression profiles (GSE64957, GSE8514, and GSE60042). Differentially expressed gene (DEG) investigation, function and pathway enrichment analysis, and protein-protein interaction (PPI) network analysis were performed by the bioinformatics analysis. For the validation with quantitative PCR, tissues from 11 patients with nonfunctioning adrenal adenoma (NFA) and 13 with APA were included in our cohort. RESULTS: In this study, the bioinformatics analysis was performed and 182 upregulated and 88 downregulated DEGs were identified. As expected, the upregulated DEGs were primarily involved in calcium ion homeostasis (p = 2.00X10-4). In the KEGG pathway analysis, calcium signaling pathway (p = 4.38X10-6) and the aldosterone synthesis and secretion (p = 8.73X10-6) were enriched. Moreover, quantitative PCR was performed to detect the expression of 7 upregulated genes (PCP4, ATP2A3, CYP11B2, CLCN5, HTR4, VDR, and AQP2) among the intersection of DEGs. The mRNA levels of CYP11B2, HTR4, and AQP2 were significantly increased in APA samples compared to NFA (24.420 folds of NFA, p < 0.001; 3.753 folds of NFA, p = 0.002; and 11.487 folds of NFA, p = 0.018). CONCLUSION: In summary, the present study showed several candidate genes with high expression from bioinformatics analysis and our cohort. Also, the DEGs were enriched in aldosterone synthesis and secretion and calcium signaling pathway as expected.

Recurrent Germline Mutations of CHEK2 as a New Susceptibility Gene in Patients with Pheochromocytomas and Paragangliomas.

PURPOSE: Recently, pheochromocytomas and paragangliomas (PPGLs) have been strongly suspected as hereditary tumors, as approximately 40% of patients carry germline mutations. In the cancers where defects occur to corrupt DNA repair and facilitate tumorigenesis, a CHEK2 strong association has been observed. Therefore, the purpose of this study was to investigate the effect of CHEK2 mutations for its possible pathogenicity in PPGLs. METHODS: Four patients with CHEK2 mutations were recruited, as previously detected by the whole exome sequencing. Sanger sequencing was used to verify the germline mutations as well as the loss of heterozygosities (LOHs) in their somatic DNAs. Immunohistochemistry was used to analyze the expression of CHEK2 and its downstream target p53 Ser20 (phosphorylated p53). RESULTS: The average age of studied patients was 44.25 ± 11.18 years, at the time diagnosis. One patient had multiple tumors which recurred quickly, while two patients had distant metastasis. None of the patient had any relevant family history. Four germline CHEK2 mutations were identified (c.246_260del; c.715G > A; c.1008+3A > T; and c.1111C > T). All the patients were predicted to have either pathogenic or suspected pathogenic mutations. There was no LOH of CHEK2 gene in somatic DNAs found. Additionally, neither CHEK2 proteins nor its downstream target p53 Ser20 were expressed in the tumor tissues. The inactivation of CHEK2 leads to the decrease in the p53 phosphorylation, which might promote tumorigenesis. CONCLUSIONS: For the first time, CHEK2 was identified as a susceptibility gene for PPGLs. However, the penetrance of CHEK2 gene with genotype-phenotype correlation needs to be investigated.

Surgical Outcomes of Aldosterone-Producing Adenoma on the Basis of the Histopathological Findings.

Introduction: Previous studies on the surgical outcomes of aldosterone-producing adenoma (APA) patients were mainly based on the histopathological diagnosis of HE staining or adrenal venous sampling (AVS) instead of the functional pathology. The aim of the present study was to evaluate the surgical outcomes of APA patients based on the functional pathological diagnosis of APA according to HISTALDO (histopathology of primary aldosteronism) consensus. Methods: Clinical data of 137 patients with suspected APA were analyzed retrospectively. All patients had hypertension and spontaneous hypokalemia. In all patients, CT showed a unilateral solitary hypodense adrenal lesion, and a contralateral adrenal gland of normal morphology. Tumors were removed and immunostained for CYP11B2, and their pathology were identified based on HISTALDO consensus. Patients were followed up 6 to 24 months after operation. Results: Among 137 cases of presumptive APA diagnosed by CT, 130 (95%) cases were pathologically diagnosed with classical pathology, including 123 APA(90%) and 7 aldosterone-producing nodule (APN) (5%). 7 cases (5%) had non-functioning adenoma (NFA) with aldosterone-producing micronodule (APM) or multiple aldosterone-producing micronodule (MAPM) in the surrounding adrenal tissue. In all 137 patients, hypertension was complete or partial clinical success postoperatively. Complete clinical success was achieved in 73 (53%), and partial clinical success was achieved in 64 (47%) cases. Serum potassium level recovered to normal in all. In 123 patients with APA, complete clinical success was reached in 67 (54%), and partial clinical success was reached in 56 (46%) cases. Gender, duration of hypertension and the highest SBP were significant independent predictors for cure of APA after surgery. A multiple logistic regression model integrating the three predictors was constructed to predict the outcome, which achieved a sensitivity of 72.4% and a specificity of 73.1%. Conclusion: The specificity of CT in the diagnosis of APA and APN patients with hypokalemia was 95%. All patients achieved complete or partial clinical success after surgery. Gender, duration of hypertension and the highest SBP were independent predictors for the postoperative cure of APA.

Differences in Clinical Manifestations and Tumor Features Between Metastatic Pheochromocytoma/Paraganglioma Patients With and Without Germline SDHB Mutation.

OBJECTIVE: To compare metastatic pheochromocytoma/paraganglioma (MPP) patients with germline SDHB mutations (SDHB MPP) and without SDHB mutations (non-SDHB MPP) in terms of baseline clinical manifestations, tumor characteristics, and outcomes. METHODS: Clinical data were retrospectively reviewed in 101 MPP patients, including 34 SDHB MPP patients and 61 non-SDHB MPP patients. RESULTS: SDHB MPP patients presented at a younger age at onset, diagnosis, or metastasis (25 ± 16 vs 36 ± 14, 28 ± 17 vs 38 ± 15, and 31 ± 17 vs 44 ± 14 years old, respectively, P < .01 for all) than non-SDHB patients. Compared with their non-SDHB counterparts, SDHB patients were more likely to have paragangliomas (83% vs 47%, P < .05), synchronous metastases (44% vs 23%, P < .05), bone metastases (80% vs 48%, P < .01), and a shorter progression-free survival (3 years vs 5 years, P < .01). The Ki-67 index was higher in SDHB tumors (P < .05). The 5- and 10-year survival rates were 79% and 74%, respectively, in all patients. Seventeen patients died from MPP, and the time from metastasis to death in patients who had received systemic therapy was significantly longer than in those who had not (3.1 ± 1.5 vs 1.4 ± 0.7 years, P < .01). CONCLUSION: Compared with MPP patients without SDHB mutations, MPP patients with SDHB mutations were younger at onset, diagnosis, or metastasis; had a higher incidence of synchronous metastases, higher ratio of paraganglioma, and higher Ki-67 index; had a shorter postoperative progression-free survival; and were more likely to develop bone metastasis or sole liver metastasis. Our results suggest that patients with SDHB mutations should be identified early and monitored regularly to achieve optimal clinical outcomes.

Genetic and Clinical Profiles of Pheochromocytoma and Paraganglioma: A Single Center Study.

Pheochromocytoma/paraganglioma (PPGL) has a high genetic heterogeneity with 40% germline variants in known pathogenic genes. Data in Chinese on this aspect are scanty. To detect the genetic and clinical profile of Chinese PPGL patients, we examined the variants of 12 known germline pathogenic genes (SDHA, SDHB, SDHC, SDHD, SDHAF2, FH, VHL, RET, NF1, MAX, TMEM127, and KIF1B) by next-generation sequencing and Sanger sequencing in 314 Chinese PPGL subjects. Twenty nine percent of Chinese PPGL patients had germline variants and SDHB was the most frequently mutated (14.6%). The most frequent SDHB variants were in exon 2, exon 7, and IVS 7. Pathogenic variants were more likely to occur in metastatic PPGL patients, paragangliomas, and patients under 30, with the ratio being 50.7% (35/69), 35.9% (56/156), and 49.5% (52/105), respectively. Our cohort included 314 patients from a single setting. The genetic and clinical features of Chinese PPGL patients were unique in some aspects compared to their non-Chinese counterparts. Identification of genotype-phenotype relation can serve as an effective tool for genetic prioritization and clinical decision-making.

A Novel Phenotype of Germline Pathogenic Variants in MAX: Concurrence of Pheochromocytoma and Ganglioneuroma in a Chinese Family and Literature Review.

Background:MYC associated factor X (MAX) is a tumor suppressor gene and has been identified as one of the pathogenic genes of hereditary pheochromocytoma (PCC). To date, there have been no reports of ganglioneuroma (GN) with MAX variants. Case Presentation: The proband was a 45-years-old Chinese female with paroxysmal hypertension and palpitations who had undergone adrenalectomy for PCC 14 years ago. Her plasma free normetanephrine and 24-h urinary norepinephrine excretion were significantly increased, and abdominal computed tomography (CT) revealed an irregular mass in the left adrenal region, suggesting a recurrence of PCC. The mass was surgically removed and pathologically diagnosed as PCC with lymph node metastasis. The proband's son suffered from paroxysmal hypertension and palpitations. His plasma free metanephrine levels were normal. CT revealed a mass in the right adrenal. The tumor was surgically removed, and the pathological diagnosis was GN. Genetic testing of peripheral blood DNA revealed that the proband and her son had germline pathogenic MAX variant c.C97T, p.Arg33Ter, while proband's parents did not have MAX variants. Tumor DNA sequencing showed the same MAX variant (c.C97T, p.Arg33Ter) in PCC of the proband and GN of her son, both with retention of heterozygosity. Immunohistochemistry demonstrated loss of MAX protein expression in most tumor cells in PCC of the proband and some Schwannian cells in GN of the proband's son. Conclusion: We report a family with a new clinical phenotype of germline pathogenic variants in MAX who developed both PCC and GN. Germline pathogenic variants in MAX may contribute to the development of GN. Our findings suggest that it is not just paternally inherited MAX variants that can cause tumors.

Temozolomide Is a Potential Therapeutic Tool for Patients With Metastatic Pheochromocytoma/Paraganglioma-Case Report and Review of the Literature.

Context: Metastatic pheochromocytoma/paraganglioma (MPP) therapy mainly involves radionuclide therapy, chemotherapy, and targeted therapy. In recent years, temozolomide (TMZ) showed great promise in some MMP patients, especially those with SDHB germline mutation. We reported a patient with MPP who did not have any known germline genetic change and responded remarkably well to TMZ monotherapy. Case presentation: The patient was a 41-year-old woman with local and distant recurrence (soft tissues and bone metastases) of retroperitoneal paraganglioma. She suffered from dizziness, palpitation, sweating, weight loss and constipation, with the blood pressure fluctuating substantially from 130/100 mmHg to 190/120 mmHg, although she was on phenoxybenzamine and metoprolol medication. The patient showed clinical and radiological response after 3-cycle TMZ therapy. Upon 15 cycles of TMZ therapy, her symptoms were dramatically alleviated, urinary norepinephrine excretion decreased from 1,840 µg/24 h to 206 µg/24 h, and CT showed that the lesions further shrank. Molecular profiling of the tumor tissue of the patient revealed hypermethylation of the O6-methylguanine-DNA-methyltransferase (MGMT) promoter and a negative immunostaining for MGMT. Globally, only 26 cases of MPP treated with TMZ have been described so far. TMZ is effective, especially in patients with SDHB mutation, which can be explained by the silencing of MGMT expression as a consequence of MGMT promoter hypermethylation in SDHB-mutated tumors. Although, in general, patients with SDHB mutation or MGMT promoter hypermethylation have better response to TMZ, there are also exceptions. Severe side effects are uncommon, with only 17.4% patients experiencing Grade 3 toxicities, including lymphopenia, and hypertension. Conclusions: TMZ is effective and safe in MPP patients, and, it may work better on patients with SDHB-related MPP. Measurement of MGMT expression might help assess the tumor sensitivity to TMZ but this needs further systematic investigation.

A Rare Aldosterone-Producing Adenoma Detected by 68Ga-pentixafor PET-CT: A Case Report and Literature Review.

Context: Primary aldosteronism represents an important and common cause of hypertension and is characterized by autonomous aldosterone secretion that results in severe hypertension and hypokalemia. Nonetheless, its manifestations are atypical in some cases, which renders its diagnosis difficult. Case Description: Presented in this report is a Chinese female patient with blood pressure in the high-normal range, and her parathyroid hormone was significantly elevated. Elevated plasma aldosterone concentration plus suppressed plasma rennin activity was suggestive of primary aldosteronism. 68Ga-pentixafor positron emission tomography/computed tomography revealed an aldosterone-producing adenoma, which was globally the second of its kind ever reported so far. Moreover, the tumor was located in an extremely rare area. Conclusions: Patients with primary aldosteronism may present with normal or high-normal blood pressure and a significantly elevated parathyroid hormone. 68Ga-pentixafor PET/CT is potentially a helpful tool for the non-invasive characterization of patients with primary aldosteronism.

AZD8055 inhibits ACTH secretion in a case of bilateral ACTH-secreting pheochromocytoma.

Ectopic adrenocorticotropic hormone (ACTH) syndrome is usually caused by pulmonary and bronchial tumors and rarely by pheochromocytoma. To date, the majority of ACTH-secreting pheochromocytomas have been unilateral, with the exception of two cases. A 54-year-old male presented with hypertension and bilateral adrenal tumors. The patient did not report having classic cushingoid features or experience of paroxysmal headaches or sweating, but presented with a slight abdominal obesity. The patient was clinically and pathologically diagnosed with bilateral ectopic ACTH-secreting pheochromocytomas. Whole-exome sequencing demonstrated that the 19 pheochromocytoma-related genes were unmutated. The pheochromocytomas on the two sides exhibited negative ACTH staining, but the ACTH concentration was markedly higher in the tumor tissue homogenates than in those tumors of another 3 patients with non-ACTH secretion pheochromocytoma. Electron microscopy identified two types of neuroendocrine cells in the tumor tissues. Primary culture of the pheochromocytoma cells revealed that ACTH secretion was inhibited by a mechanistic target of rapamycin inhibitor, AZD8055.

Juxtaglomerular cell tumor: Clinical and immunohistochemical features.

Juxtaglomerular cell tumor (JGCT) is a rare tumor, with approximately 100 cases reported in the literature. The authors respectively studied the clinical data of 11 patients diagnosed with JGCT in Peking Union Medical College Hospital from 2004 to 2014, and investigated the immunohistochemical profiles in 10 tumors. Nine of the 11 patients were diagnosed before the age of 40 years. Hypertension was present in all patients, while hypokalemia occurred in seven of 11 patients. Computed tomography detected JGCTs with a sensitivity of 100%. Immunoreactivities for CD34 and vascular endothelial growth factor were observed in most tumor specimens, suggesting that JGCTs express a variety of vessel-related immunohistochemical markers, although JGCTs are considered a tumor without abundant blood supply. Nuclear accumulation of cyclin D1 was common in JGCTs. Results from immunohistochemistry were negative for BRAF, HER2, and TFE3, suggesting that BRAF, HER2, and TFE3 genes might not play a part in tumorigenesis in JGCTs.

Mutation profile and treatment of Gitelman syndrome in Chinese patients.

BACKGROUND: Gitelman syndrome (GS) is a rare autosomal recessive disease caused by loss-of-function mutations in the SLC12A3 gene, and is characterized by hypokalemia and metabolic alkalosis. In this study, we aimed to study the genotype, phenotype, and treatment in 42 GS patients, the largest sample size so far in mainland China. METHOD: We retrospectively studied the clinical data and genetic characteristics of 42 patients diagnosed with GS in Peking Union Medical College Hospital from 2012 to 2015. Therapeutic efficacy of spironolactone and potassium supplements was also studied retrospectively. RESULTS: Eighty-one mutation alleles were found in 42 patients, and total of 52 distinctly different mutation alleles were identified, of which 15 were new mutation alleles. p.Asp486Asn was a hotspot in our series, with the allele frequency being 19.7 % (16/81), and was found in 13 patients (31.0 %). Treatment with spironolactone or potassium supplements alone significantly increased serum potassium concentration by 0.36 ± 0.37 and 0.45 ± 0.35 mmol/l, respectively (both P < 0.05), and combined therapy with spironolactone and potassium increased serum potassium concentration by 0.69 ± 0.64 mmol/l (P < 0.05). CONCLUSIONS: 18.5 % (15/81) mutation sites identified in 42 Chinese GS patients are novel. p.Asp486Asn mutation is a hotspot, which is different from the reports from other countries. Spironolactone could moderately elevate serum potassium level, and spironolactone in combination with potassium supplements tended to be more effective.