Metastatic Pheochromocytoma Research Articles

Metastatic composite pheochromocytoma manifesting as severe bone pain

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Posterior reversible encephalopathy syndrome (PRES) as a presentation of a metastatic pheochromocytoma (PHEO)

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

PO-1574 Spine stereotactic radiosurgery in the management of metastatic pheochromocytoma

PO-1574 Spine stereotactic radiosurgery in the management of metastatic pheochromocytoma

Metastatic pheochromocytoma and paraganglioma: a retrospective multicentre analysis on prognostic and predictive factors to chemotherapy.

Prognostic and predictive markers in metastatic pheochromocytoma and paraganglioma (mPPGL) are unknown. We aimed to evaluate epidemiology of mPPGL, and prognostic factors of overall survival (OS) and predictive markers of treatment duration with first-line chemotherapy (TD1L). Retrospective multicentre study of adult patients with mPPGL treated in Latin American centres between 1982 and 2021. Fifty-eight patients were included: 53.4% were female, median age at diagnosis of mPPGL was 36 years and 12.1% had a family history of PPGL. The primary site was adrenal, non-adrenal infradiaphragmatic and supradiaphragmatic in 37.9%, 34.5% and 27.6%, respectively. 65.5% had a functioning tumour and 62.1% had metachronous metastases. Positive uptakes were found in 32 (55.2%) 68Gallium positron emission tomography (PET/CT), 27 (46.6%) 2-deoxy-2-[fluorine-18]fluoro-D-glucose PET/CT and 37 (63.8%) of 131Iodine-metaiodobenzylguanidine (MIBG) tests. Twenty-three (40%) patients received first-line chemotherapy, with cyclophosphamide, vincristine and dacarbazine used in 12 (52%) of patients. At a median follow-up of 62.8 months, median TD1L was 12.8 months. Either functional exams, tumour functionality, pathological characteristics or primary tumour location were significantly associated with response or survival. Yet, negative MIBG, Ki67 ≥ 10%, infradiaphragmatic location and functional tumours were associated with numerically inferior OS. In patients with mPPGL, prognostic and predictive factors to chemotherapy are still unknown, but negative MIBG uptake, Ki67 ≥ 10%, infradiaphragmatic location and functional tumours were numerically linked to worse OS. Our results should be further validated in larger and independent cohorts.

Prediction of metastatic pheochromocytoma and paraganglioma: a machine learning modelling study using data from a cross sectional cohort

Prediction of metastatic pheochromocytoma and paraganglioma: a machine learning modelling study using data from a cross sectional cohort

Genomic and immune landscape Of metastatic pheochromocytoma and paraganglioma

The mechanisms triggering metastasis in pheochromocytoma/paraganglioma are unknown, hindering therapeutic options for patients with metastatic tumors (mPPGL). Herein we show by genomic profiling of a large cohort of mPPGLs that high mutational load, microsatellite instability and somatic copy-number alteration burden are associated with ATRX/TERT alterations and are suitable prognostic markers. Transcriptomic analysis defines the signaling networks involved in the acquisition of metastatic competence and establishes a gene signature related to mPPGLs, highlighting CDK1 as an additional mPPGL marker. Immunogenomics accompanied by immunohistochemistry identifies a heterogeneous ecosystem at the tumor microenvironment level, linked to the genomic subtype and tumor behavior. Specifically, we define a general immunosuppressive microenvironment in mPPGLs, the exception being PD-L1 expressing MAML3-related tumors. Our study reveals canonical markers for risk of metastasis, and suggests the usefulness of including immune parameters in clinical management for PPGL prognostication and identification of patients who might benefit from immunotherapy.

Outcomes of systemic treatment in patients with metastatic pheochromocytoma and paraganglioma: A single center retrospective analysis.

2 Background: Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumors arising from chromaffin cells of the adrenal medulla or extra-adrenal paraganglia. Although 15-17% of patients develop metastatic disease, there are very limited systemic treatment options. In this study, we aimed to evaluate the treatment landscape and outcome in PPGL patients retrospectively. Methods: Between December 2004 and December 2021, 33 patients were diagnosed with metastatic PPGLs and received systemic treatment at the Department of Oncology, Asan Medical Center, Seoul, South Korea. Metastatic PPGLs included a locally advanced unresectable disease, initially metastatic disease, and recurrent disease. Systemic treatment involves cytotoxic chemotherapy and targeted agents, and efficacy analysis included the objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results: The median age at diagnosis was 49 years (range, 15–74), 17 patients were male (52%), and 22 patients were pheochromocytomas (67%). Disease status was recurrent (73%), initially metastatic (21%), and locally advanced (6%). Of 23 patients who underwent germline tests, 14 (61%) were identified with germline mutations, and the most frequent mutation was SDHB germline mutation (n=8, 57%). Of the 33 patients, 18 received chemotherapy with cyclophosphamide, vincristine, and dacarbazine (CVD). The ORR was 22% (4/18; all PR), and the disease control rate (DCR) was 67% (n=12). The median PFS was 7.9 months [95% confidence interval (CI), 1.6-not available (NA)], and the median OS was 36.2 months (95% CI, 5.7-NA). Six patients were treated with sunitinib, and the ORR was 33% (2/6; all PR), and the DCR was 83% (n=5). The median PFS was 14.6 months (95% CI, 3.6-NA), and the median OS was 14.6 months (95% CI, 3.6-NA). In CVD treatment, patients with SDHB/SDHD mutation (either germline or somatic) were significantly associated with superior OS & PFS compared with the non-SDHB/SDHD mutation group, with a median OS of 94.0 months vs. 5.7 months (P = 0.01) and a median PFS of 20.1 months vs. 1.6 months (P = 0.03), respectively. In the SDHB/SDHD mutation group, the ORR was 50% (3/6, all PR), and the DCR was 100% (n=6), but in a non-SDHB/SDHD mutation group, the ORR was 11% (1/9, PR) and the DCR was 44% (n=4). Conclusions: Systemic treatment with CVD and sunitinib provided meaningful disease control, and outcomes were comparable with previous data. Especially, CVD treatment was effective in patients with SDHB/SDHD mutation, and further validation is needed in future studies.

Proposed MIBG Scan-Based Tumor Response Criteria of High-Specific-Activity 131 I-MIBG Therapy in Metastatic Pheochromocytoma/Paraganglioma.

High-specific-activity 131 I-MIBG (Azedra) is the only Food and Drug Administration-approved therapy for metastatic pheochromocytomas and paragangliomas, which are rare neuroendocrine tumors with limited treatment options. Based on our experience, we proposed here functional imaging-based tumor response criteria for these patient cohorts. Each response category was illustrated with typical sample cases, and clinical correlation was provided.

PS-R03-4: TRANSARTERIAL EMBOLIZATION, THORACIC SPINE DECOMPRESSION AND FUSION OF METASTATIC PHEOCHROMOCYTOMA: A CASE REPORT

Surveillance of metastatic lesions and biochemical control of catecholamines in patients with malignant pheochromocytoma remain a fundamental problem to be solved. Here we present a 60-year-old male who visited a local clinic because of headache, sweating, malaise, and loss of body weight. Hypertension, orthostatic hypotension, along with remarkable increase in serum and urine noradrenaline, and urine metanephrine and vanillylmandelic acid were noted, and pheochromocytoma was suspected accordingly. Magnetic resonance imaging failed to reveal adrenal gland or sympathetic plexuses, yet it uncovered metastatic lesions in the liver and spine. Functional imaging study using 131I-Metaiodobenzylguanidine (MIBG) scan detected notable uptake in the spinal lesion, albeit not in the hepatic lesion. On the other hand, positron emission tomography with fluorodeoxyglucose (FDG-PET) disclosed FDG uptake both in the hepatic and spinal masses. Biopsy of the hepatic tumors revealed chromogranin A-positive clusters of cells, a finding consistent with metastatic pheochromocytoma. Transarterial embolization (TAE) of the metastatic tumors in the liver was performed for the purpose of tumor mass reduction. Additionally, TAE followed by resection of the spinal lesion was conducted. Pathological examination of the spinal tumor also showed chromogranin A-positive cells, leading to diagnosis of malignant pheochromocytoma. Crucially, TAE of the liver and spinal tumors resulted in dramatic reduction of catecholamine production, likely constituting an effective therapeutic strategy against metastatic pheochromocytoma (Homma, et al. Hypertens Res 2006). Afterwards, the patient became unable to walk because of weakness in the left leg at the age of 64. It seemed attributed to spinal cord compression from the tumor at the level of thoracic vertebrae 7. The patient underwent posterior decompression and fusion, and his muscle strength of the left leg was recovered. At the age of 65, the patient developed paralytic ileus following a surgery against metastatic tumors in the skull. In this case report, we discuss early detection of metastatic lesions and biochemical control of catecholamines in patients with malignant pheochromocytoma.

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.

PD-L1 expression and association with genetic background in pheochromocytoma and paraganglioma.

Metastatic pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors associated with poor prognosis and limited therapeutic options. Recent advances in oncology-related immunotherapy, specifically in targeting of programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) pathways, have identified a new treatment potential in a variety of tumors, including advanced and rare tumors. Only a fraction of patients being treated by immune checkpoint inhibitors have shown to benefit from it, displaying a need for strategies which identify patients who may most likely show a favorable response. Building on recent, promising outcomes in a clinical study of metastatic PPGL using pembrolizumab, a humanized IgG4κ monoclonal antibody targeting the PD-1/PD-L1 pathway, we examined PD-L1 and PD-L2 expression in relation to oncogenic drivers in our PPGL patient cohort to explore whether expression can predict metastatic potential and/or be considered a predictive marker for targeted therapy. We evaluated RNA expression in the NIH cohort of 48 patients with known genetic predisposition (sporadic; pseudohypoxia: SDHB, VHL, EPAS1, EGLN1; kinase signaling: RET, NF1) and 6 normal medulla samples (NAM). For comparison, 72 PPGL samples from The Cancer Genome Atlas (TCGA) were used for analysis of gene expression based on the variant status (pseudohypoxia: SDHB, VHL, EPAS1, EGLN1; kinase signaling: NF1, RET). Expression of PD-L1 was elevated in the PPGL cohort compared to normal adrenal medulla, aligning with the TCGA analysis, whereas PD-L2 was not elevated. However, expression of PD-L1 was lower in the pseudohypoxia cluster compared to the sporadic and the kinase signaling subtype cluster, suggesting that sporadic and kinase signaling cluster PPGLs could benefit from PD-1/PD-L1 therapy more than the pseudohypoxia cluster. Within the pseudohypoxia cluster, expression of PD-L1 was significantly lower in both SDHB- and non-SDHB-mutated tumors compared to sporadic tumors. PD-L1 and PD-L2 expression was not affected by the metastatic status. We conclude that PD-L1 and PD-L2 expression in our cohort of PPGL tumors was not linked to metastatic behavior, however, the presence of PPGL driver mutation could be a predictive marker for PD-L1-targeted therapy and an important feature for further clinical studies in patients with PPGL.

ODP041 Hearing Loss Reveals Dopamine-secreting Metastatic Paraganglioma

Abstract Background Paragangliomas are neuroendocrine tumors arising from chromaffin cells in extra-adrenal parasympathetic or sympathetic tissues. Frequently they produce catecholamines such as epinephrine and norepinephrine which cause adrenergic symptoms. Rarely, paragangliomas produce only dopamine. These tumors carry a worse prognosis than other types of paragangliomas, especially when associated with loss of SDH-B. Case A 41 year old African American female with developmental delay, allergic rhinitis, OSA, and obesity presented to a primary care clinic for evaluation of hearing loss and left ear pain. Patient was treated for acute otitis media but symptoms failed to resolve. She was referred to audiology where she was found to have a mixed conductive and sensorineural hearing loss on the left. Despite using hearing aids, a year later the patient presented to an ENT clinic with several weeks of worsening left aural fullness and decreased hearing. On otoscopy, a mass was visualized in the middle ear. CT scan identified a lytic lesion at the jugular foramen extending into the middle ear; MR of the inner auditory canal was concerning for a paraganglioma. PET CT revealed widely metastatic disease including FDG avid cervical and supraclavicular lymph nodes, pulmonary nodules, hepatic lesions, and sclerotic lesions in the vertebral column and right humerus. Biopsy of an hepatic lesion confirmed metastatic paraganglioma with loss of SDH-B. Labs were consistent with dopamine excess. A 24 hour urine dopamine was 1020 mcg/24 hour (normal 65-400) with plasma dopamine elevated at 191 pg/mL (normal <30). A 24 hour urine norepinephrine level was mildly elevated at 85 mcg/24 hours (normal 15-80) but plasma norepinephrine and epinephrine were both normal. The patient denied any history of palpitations, flushing, headaches, or chest pain. She was briefly started on doxazosin but this was later discontinued as metanephrines and normetanephrines were not significantly elevated. The tumor was not amenable for surgery. Ultimately after discussion with oncology, the patient opted to proceed with temozolomide and capecitabine chemotherapy. Discussion It is important to recognize differences in treating dopamine secreting paragangliomas compared with other catecholamine producing tumors. Preoperative alpha blockade is not routinely recommended as it may cause hypotension and postoperative cardiovascular collapse. While chemotherapy with Cyclophosphamide–dacarbazine–vincristine has historically been used for metastatic paragangliomas, temozolomide is now showing benefit in cases with SDH-B mutation. Sources cited: Foo, S. H., et al. "Dopamine-secreting phaeochromocytomas and paragangliomas: clinical features and management." Singapore Med J 51.5 (2010): e89-e93. Hadoux, J., Favier, J., Scoazec, J. -Y., et al (2014),SDHB mutations are associated with response to temozolomide in patients with metastatic pheochromocytoma or paraganglioma. Int. J. Cancer, 135: 2711-2720. https://doi.org/10.1002/ijc.28913. Presentation: No date and time listed

RF19 | PSUN367 Urinary bladder Paragangliomas – A Case series

Abstract Introduction Paragangliomas (PGL) are rare neuroendocrine tumours and account for approximately 10% of all chromaffin tumours. They may occur in the retroperitoneum, mediastinum, skull and the urinary bladder. Paragangliomas of the urinary bladder are rare entities accounting for 10% of all paragangliomas and 0.06% of all bladder tumours. Approximately 10% of urinary bladder paragangliomas are malignant. Bladder paragangliomas can be either functional or non-functional. Main symptoms of functional PGLs are due to catecholamine excess with palpitations, paroxysmal hypertension during micturition, sweating and headaches. Functional bladder PGL are diagnosed on biochemical analysis. Non-functional bladder PGLs present with haematuria and are often misdiagnosed as bladder cancer as they may cystoscopically and histologically resemble a urothelial neoplasm. Clinical cases: We present a case series of 4 surgically treated patients with urinary bladder paragangliomas who presented to Cambridge University Hospital over the last 3 years. All patients were female with an age range between 21 and 44 years. All four patients had SDHB deficient tumours, and all four patients were diagnosed with a pathogenic variant in the SDHB gene. Three patients had no family history of SDHx associated neoplasia whereas one had a paternal aunt who died from a metastatic pheochromocytoma. Three patients had presented with palpitations and hypertensive episodes, one of whom experienced symptoms while micturating. Biochemical analysis revealed elevated plasma normetadrenaline levels in all patients. On presentations, one patient had a synchronous paratracheal paraganglioma while two patients had lymph node metastasis. All patients were surgically treated with two patients undergoing fertility preserving cystectomy and bladder substitution, one undergoing partial cystectomy, radical hysterectomy and ureteric implantation and one managed with robot-assisted partial cystectomy. None of the patients have evidence of biochemical or radiological tumour recurrence on follow-up with a mean follow-up time of 23 months (range 12 to 40 months). Conclusion and points for discussion The diagnosis of urinary bladder PGL is challenging. Biochemical assessment to assess catecholamine production and imaging studies like CT, MRI and NM Ga68 DOTATATE PET CT are helpful modalities in diagnosis. Patients presenting with extra adrenal paragangliomas including bladder paragangliomas require genetic testing because of the strong hereditary predisposition, with mutations in the SDHx genes being most common with this clinical phenotype. The surgical approach should be tailored to the individual patient, agreed by a multi-disciplinary team and the risk of malignancy should be weighed against the potential morbidity associated with a curative oncological surgery. As urinary bladder PGLs have malignant potential and are frequently hereditary (as demonstrated in this series), lifelong follow-up is required to screen for synchronous tumours and tumour recurrence. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m., Sunday, June 12, 2022 12:42 p.m. - 12:47 p.m.

ODP020 A Challenging Case of Poorly Differentiated Carcinoma with Neuroendocrine Differentiation and Adrenal Mass

Abstract Background Neuroendocrine tumors (NETs) account for about 0.5% of all newly diagnosed malignancies. The most frequent primary sites are the gastrointestinal tract or pancreatic (62%-67%) and the lung (22%-27%). All poorly differentiated NETs have a Ki-67 index of greater than 20% and WHO grade of 3. The determination of the site of origin can be challenging in widely metastatic poorly differentiated NETs. Clinical Case A 51-year man with a history of hypertension and type 2 diabetes mellitus presented with angioedema while on lisinopril for years. Apart from a month's history of bilateral flank pain, he denied diarrhea, flushing, stridor, or shortness of breath. CT abdomen showed an 8.2×8. 0×7.9 cm right adrenal mass with a few punctate calcifications, hepatomegaly with multiple liver metastases, multiple retroperitoneal, hepatoduodenal, retrocrural adenopathy, and T4 metastatic lesion. CT chest showed bulky mediastinal and supraclavicular lymph nodes with trachea narrowing. All those lesions were FDG avid on PET/CT scan. Core biopsy of right supraclavicular lymph node revealed a poorly differentiated carcinoma with neuroendocrine differentiation and high proliferative index (25-50%). On cell block, it was negative for (AE1/AE3 (-), CAM5.2 (-), CK7, CK20, vimentin, desmin, CEA, EMA, CD45, CD20, and TTF-1 but positive for CK903 (focal +), synaptophysin (+), chromogranin (+), calretinin (focally +), inhibin (focally +). Based on the immunohistochemical stain, it was concluded as a metastatic small cell carcinoma of unknown origin. He was treated with carboplatin, etoposide, and atezolizumab and received 5 cycles. Endocrine was consulted two months after his initial presentation. Urine normetanephrine was > 4-fold elevated. Blood pressure was controlled on Doxazosin at 4 mg bid. The 10 gene-panel for hereditary pheochromocytoma and Paraganglioma (PGL) was negative. There was a progression of mediastinal adenopathy while on treatment with narrowing of proximal intrathoracic trachea requiring elective tracheostomy. Based on imaging findings and elevated normetanephrine, we believe he has metastatic pheochromocytoma and PGL. His chemo regimen was switched to Cyclophosphamide, Vincristine, and Dacarbazine (CVD). He finished 8 cycles of CVD with an overall reduction in the size of lymph nodes (both above and below the diaphragm) and right adrenal mass. His plasma normetanephrine level was also significantly improved. Presentation: No date and time listed

PSUN27 Largest Cohort of Cervical Spine Metastases of Pheochromocytoma/Paraganglioma in the Setting of SDHB Mutation

Abstract Background Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors arising from chromaffin cells in adrenal or extra-adrenal locations, respectively. Overall, 10 to 20% of PPGLs are metastatic, with higher metastatic potential observed in succinate dehydrogenase subunit B (SDHB)-related tumors (up to 90%). Metastatic PPGLs are diagnosed based on the presence of tumor cells of chromaffin origin in a location outside the site of normal development (adrenal medulla and the sympathetic chain) in the bones and lymphatic nodes per 2017 WHO guidelines. Studies evaluating both metastatic pheochromocytomas and extra-adrenal PGLs have reported bone to be the most common site of metastasis. Clinical Case We reviewed the metastatic patients in our PPGL cohort and found 40 (29.85%) out of 134 patients with SDHB-related metastatic PPGLs developing metastatic lesions in the cervical spine. The related descriptive analyses were as follows: 25 (62.5%) were males, 15 (37.5%) females. Fourteen patients (35%) have died due to metastatic PPGL complications. The average age of patients at the time of the primary tumor diagnosis was 30.3 ± 35 years and the age at the initial metastatic tumor diagnosis was 34 ± 33 years. The average time interval to metastatic disease was 7.4 ± 38 years. At their initial presentation, there were 25 (62.5%) patients with solitary tumors; 1 (2.5%) with multiple primary tumors; and 14 (35%) with metastatic tumors. All the patients either developed or had metastatic lesions in the cervical vertebrae. Nine (22.5%) patients required surgical fusions of the vertebrae to manage their pathological fractures and another 9 (22.5%) patients received radiation therapy. Conclusion Genetic testing is recommended for all patients with PPGLs. Genetic analysis, especially finding a SDHB mutation may be helpful in determining metastatic potential. Most patients with spinal metastatic lesions are asymptomatic, but when clinical symptoms arise, the most common clinical symptom involves pain and neurological deficit. Metastasis to the spine is an important complication that can lead to significant pain and disability and requires surgical interventions or radiotherapy. Awareness for such spinal tumors is essential for offering the correct treatment to the patients. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

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

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. 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. 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. 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.

Bladder Paraganglioma Presenting as Post-Micturition Syncope.

A 22-year-old woman presented with a 12-year history of intensifying paroxysms of anxiety, palpitations and recurrent syncope following micturition. The patient was referred to endocrinology upon discovery of hypertension. An extended family history revealed metastatic phaeochromocytoma and paraganglioma in two grand-uncles. Clinical examination revealed hypertension, with a mean 24-hour ambulatory blood pressure of 150/100 mmHg. Supine plasma normetanephrines were markedly elevated with a raised 3-methoxytyramine, while plasma metanephrines were normal. Computed tomography identified a 4.4 cm mass at the right inferolateral margin of the bladder wall. Scintigraphic imaging confirmed unifocal bladder lesion uptake with no additional metastatic lesions. Following pre-operative alpha blockade, the patient underwent a partial cystectomy. Histology confirmed a paraganglioma, and SDHB staining was lost in neoplastic cells consistent with an SDHB-related paraganglioma. Plasma normetanephrine, 3-methoxytyramine and blood pressure returned to normal postoperatively. Genetic screening identified a germline heterozygous SDHB gene variant c.723C>G. Bladder paragangliomas are a rare but important differential to consider when investigating post-micturition syncope. An extended family history should be sought and suspicion for a genetic cause should be raised, especially when the condition presents at a young age. This is the first reported case describing phaeochromocytoma or paraganglioma with the SDHB gene variant c.723C>G.LEARNING POINTSBladder paragangliomas are a rare neuroendocrine tumour which should be considered when assessing patients with haematuria and hypertension, headache, palpitations, sweating and facial pallor with micturition.This case highlights the importance of a thorough clinical history with an extended family history and examination in the setting of micturition syncope, which can rarely occur with bladder paraganglioma.Young age at presentation, a family history of phaeochromocytoma and paraganglioma (PPGL), unusual paraganglioma location, mutifocality and aggressive disease should raise the suspicion for a genetic predisposition to PPGL.

Hemodynamics in Patients With Pheochromocytoma or Paraganglioma Undergoing Non-neuroendocrine Operations.

Surgical resection of pheochromocytoma and paraganglioma (PPGL) may be associated with excessive hemodynamic variability. Whether hemodynamic variability occurs in patients with undiagnosed PPGL undergoing unrelated, non-neuroendocrine, operations is unknown. We identified patients who underwent non-neuroendocrine surgical procedures up to 5y before pathologic diagnosis of PPGL. For each PPGL, two non-PPGL patients were matched based on sex, age, type, and year of operation. Electronic medical records were reviewed for intraoperative blood pressures, heart rates, and hemodynamic variability was assessed with range (maximum-minimum), standard deviation, coefficient of variation, and average real variability. Thirty-seven PPGL patients underwent operations preceding the diagnosis of PPGL: 25 pheochromocytomas, 11 paragangliomas, and one metastatic pheochromocytoma. Median interquartile range tumor size at diagnosis was 35mm (23 to 60). The time from index operation to PPGL diagnosis was ≤12mo in 21 (56.8%) patients. In 23 (62.2%) patients, the subsequently diagnosed PPGL was functional. Fifteen (40.5%) PPGL and 20 (27.0%) control patients were preoperatively treated for hypertension (P=0.149). Maximum intraoperative systolic BP was >180mmHg for 4 (10.8%) PPGL patients and 3 (4.1%) controls (P=0.219). Two PPGL patients had intraoperative systolic BP >230mmHg. No significant differences were found with all other measures of intraoperative hemodynamic variability. Similarly, in secondary analysis there was no significant difference in intraoperative hemodynamic variability between biochemically active PPGL and their respective controls. Patients with undiagnosed PPGL undergoing a wide variety of non-neuroendocrine operations had intraoperative hemodynamic variability comparable to non-PPGL patients undergoing the same type of procedures.

Performances of Functional and Anatomic Imaging Modalities in Succinate Dehydrogenase A-Related Metastatic Pheochromocytoma and Paraganglioma.

Simple SummaryPheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine cancers which carry the risk of metastatic disease. Pathogenic variants in the succinate dehydrogenase subunit A gene (SDHA) have been shown to cause metastatic disease, occurring in various regions of the body. Imaging is an early and vital step in the diagnosis and clinical care of these patients. The study here identifies which imaging modality among positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging (MRI) performs better in localizing metastatic PPGL lesions related to SDHA. The study identified that 68Ga-DOTATATE PET/CT performed best at overall lesion detection; however, 18F-FDG PET/CT performed better in certain anatomic regions of the body. A combined approach with 68Ga-DOTATATE and 18F-FDG would optimize care and guide clinicians in selecting the appropriate interventions and therapies.The study identifies the importance of positron emission tomographic (PET) and anatomic imaging modalities and their individual performances in detecting succinate dehydrogenase A (SDHA)-related metastatic pheochromocytoma and paraganglioma (PPGL). The detection rates of PET modalities—68Ga-DOTATATE, 18F-FDG, and 18F-FDOPA—along with the combination of computed tomography (CT) and magnetic resonance imaging (MRI) are compared in a cohort of 11 patients with metastatic PPGL in the setting of a germline SDHA mutation. The imaging detection performances were evaluated at three levels: overall lesions, anatomic regions, and a patient-by-patient basis. 68Ga-DOTATATE PET demonstrated a lesion-based detection rate of 88.6% [95% confidence interval (CI), 84.3–92.5%], while 18F-FDG, 18F-FDOPA, and CT/MRI showed detection rates of 82.9% (CI, 78.0–87.1%), 39.8% (CI, 30.2–50.2%), and 58.2% (CI, 52.0–64.1%), respectively. The study found that 68Ga-DOTATATE best detects lesions in a subset of patients with SDHA-related metastatic PPGL. However, 18F-FDG did detect more lesions in the liver, mediastinum, and abdomen/pelvis anatomic regions, showing the importance of a combined approach using both PET modalities in evaluating SDHA-related PPGL.

Ectopic ACTH-producing neuroendocrine tumor occurring with large recurrent metastatic pheochromocytoma: a case report

BackgroundEctopic ACTH-dependent Cushing syndrome is rarely caused by pheochromocytoma (PCC). Glucocorticoid-regulated positive feedback loops in ACTH and catecholamines were proposed in some similar cases.Case presentationWe present here an 80-year-old man who had previously undergone surgery for a left adrenal PCC and newly developed severe hypertension, hypokalemia, and typical Cushingoid manifestations. Investigations revealed hyperglycemia, hypokalemia, and extremely high catecholamines and their metabolites, ACTH and cortisol. Imaging modalities showed a recurrent large left adrenal mass positively visualized with 123I-metaiodobenzylguanidine as well as somatostatin receptor scintigraphy. Surgical interventions were not indicated; thus, metyrapone, phentolamine, and doxazocin were initiated, which successfully controlled his symptoms and biochemical conditions. With the evidence that metyrapone administration decreased ACTH and catecholamine levels, the existence of positive feedback loops was speculated. During the terminal stages of the disease, additional metyrosine treatment successfully stabilized his physiological and biochemical conditions. Upon the patient’s death, pathological autopsy was performed. Immunohistochemical analysis indicated that the tumor appeared to be co-positive with tyrosine hydroxylase (TH) as well as ACTH in most tumor cells in both PCC and liver metastasis. Most cells were clearly positive for somatostatin receptor 2 staining in the membrane compartment. The dense immunostaining of ACTH, TH, dopamine-β-hydroxylase and the large tumor size with positive feedback loops may be correlated with high levels of ACTH and catecholamines in the circulation.ConclusionsWe experienced a case of severe ectopic ACTH producing the largest reported recurrent malignant left PCC with liver metastases that presented positive feedback loops in the ACTH/cortisol and catecholamine/cortisol axes. Clinicians should be aware of the paradoxical response of ACTH on metyrapone treatment and possible steroid-induced catecholamine crisis.