Activating FGFR1 Mutations in Sporadic Pheochromocytomas.

INTRODUCTION: Pheochromocytomas are neuroendocrine tumors of the adrenal glands. Up to 40% of the cases are caused by germline mutations in one of at least 15 susceptibility genes, making them the human neoplasms with the highest degree of heritability. Recurrent somatic alterations are found in about 50% of the more common sporadic tumors with NF1 being the most common mutated gene (20-25%). In many sporadic tumors, however, a genetic explanation is still lacking. MATERIALS AND METHODS: We investigated the genomic landscape of sporadic pheochromocytomas with whole-exome sequencing of 16 paired tumor and normal DNA samples and extended confirmation analysis in 2 additional cohorts comprising a total of 80 sporadic pheochromocytomas. RESULTS: We discovered on average 33 non-silent somatic variants per tumor. One of the recurrently mutated genes was FGFR1, encoding the fibroblast growth factor receptor 1, which was recently revealed as an oncogene in pediatric brain tumors. Including a subsequent analysis of a larger cohort, activating FGFR1 mutations were detected in three of 80 sporadic pheochromocytomas (3.8%). Gene expression microarray profiling showed that these tumors clustered with NF1-, RET,- and HRAS-mutated pheochromocytomas, indicating activation of the MAPK and PI3K-AKT signal transduction pathways. CONCLUSION: Besides RET and HRAS, FGFR1 is only the third protooncogene found to be recurrently mutated in pheochromocytomas. The results advance our biological understanding of pheochromocytoma and suggest that somatic FGFR1 activation is an important event in a subset of sporadic pheochromocytomas.

A Nationwide Study of Multiple Endocrine Neoplasia Type 2A in Norway: Predictive and Prognostic Factors for the Clinical Course of Medullary Thyroid Carcinoma.

BACKGROUND: Multiple endocrine neoplasia type 2A (MEN 2A) is an autosomal dominant syndrome caused by activating germline mutations in the RET (REarranged during Transfection) proto-oncogene. MEN 2A has a strong (>95%) and age-dependent (5-25 years) clinical penetrance of medullary thyroid carcinoma (MTC). Several major studies have analyzed the predictive and prognostic factors for MEN 2A to find indicators that predict the optimal timing of prophylactic thyroidectomy. The aims of this study were to describe all known RET positive MEN 2A patients diagnosed in Norway and to evaluate the clinical course of MTC, as well as its predictive and prognostic factors. METHODS: This nationwide retrospective cohort study included data for 65 (14 index and 51 screening patients) out of a total of 67 MEN 2A patients with the RET gene mutation who were diagnosed in Norway since 1974. Data were collected by reviewing patient files. The variables analyzed were genotype, phenotype, preoperative basal calcitonin, age at thyroid surgery, central lymph node dissection and nodal status at primary surgery, number of surgical procedures, and biochemical cure. Of the 65 patients, 60 had undergone thyroid surgery. The median follow-up period was 9.9 years. The patients were divided into pre-RET-and RET-era, which included patients who had thyroid surgery before January 1, 1994, and after, respectively. RESULTS: In index and screening patients, MTC was found, respectively, in 100% and 45% of cases, central lymph node dissection at primary surgery was done for 64% and 52% of patients, and the median total number of surgical procedures was two (range 1-6) and one (range 1-4). At primary surgery, all patients (n = 13) with lymph node metastases had preoperative basal calcitonin levels ≥68 pg/mL, and all patients (n = 17) without central lymph node dissection and preoperative basal calcitonin <40 pg/mL were biochemically cured. Multivariate analysis showed that preoperative basal calcitonin was a significant predictive factor for MTC superior to age at thyroid surgery when analyzing the entire period (p = 0.009) and the RET-era separately (p = 0.021). Prognostic factors for biochemical cure were preoperative basal calcitonin, central lymph node dissection, and nodal status at primary surgery (p = 0.037, p = 0.002, and p = 0.005) when analyzing the entire period, but only nodal status at primary surgery when the RET-era was considered separately (p = 0.006). CONCLUSIONS: Preoperative basal calcitonin alone can serve as an indicator for optimal timing and the extent of thyroid surgery for MEN 2A patients that could be considered safe. The results are consistent with previously reported data.

Impact of EMG Changes in Continuous Vagal Nerve Monitoring in High-Risk Endocrine Neck Surgery.

BACKGROUND: Continuous vagal intraoperative neuromonitoring (CIONM) of the recurrent laryngeal nerve (RLN) may reduce the risk of RLN lesions during high-risk endocrine neck surgery such as operation for large goiter potentially requiring transsternal surgery, advanced thyroid cancer, and recurrence. METHODS: Fifty-five consecutive patients (41 female, median age 61 years, 87 nerves at risk) underwent high-risk endocrine neck surgery. CIONM was performed using the commercially available NIM-Response 3.0 nerve monitoring system with automatic periodic stimulation (APS) and matching endotracheal tube electrodes (Medtronic Inc.). All CIONM events (decreased amplitude/increased latency) were recorded. RESULTS: APS malfunction occurred on three sides (3%). A total of 138 CIONM events were registered on 61 sides. Of 138, 47 (34%) events were assessed as imminent (13 events) or potentially imminent (34 events) lesions, whereas 91 (66%) were classified as artifacts. Loss of signal was observed in seven patients. Actions to restore the CIONM baseline were undertaken in 58/138 (42%) events with a median 60 s required per action. Four RLN palsies (3 transient, 1 permanent) occurred: one in case of CIONM malfunction, two sudden without any significant previous CIONM event, and one without any CIONM event. The APS vagus electrode led to temporary damage to the vagus nerve in two patients. CONCLUSIONS: CIONM may prevent RLN palsies by timely recognition of imminent nerve lesions. In high-risk endocrine neck surgery, CIONM may, however, be limited in its utility by system malfunction, direct harm to the vagus nerve, and particularly, inability to indicate RLN lesions ahead in time.

Post-PET ultrasound improves specificity of 18F-FDG-PET for recurrent differentiated thyroid cancer while maintaining sensitivity.

BACKGROUND: Positron emission tomography (PET) using fluor-18-deoxyglucose (18F-FDG) with or without computed tomography (CT) is generally accepted as the most sensitive imaging modality for diagnosing recurrent differentiated thyroid cancer (DTC) in patients with negative whole body scintigraphy with iodine-131 (I-131). PURPOSE: To assess the potential incremental value of ultrasound (US) over 18F-FDG-PET-CT. MATERIAL AND METHODS: Fifty-one consecutive patients with suspected recurrent DTC were prospectively evaluated using the following multimodal imaging protocol: (i) US before PET (pre-US) with or without fine needle biopsy (FNB) of suspicious lesions; (ii) single photon emission computed tomography (≥3 GBq I-131) with co-registered CT (SPECT-CT); (iii) 18F-FDG-PET with co-registered contrast-enhanced CT of the neck; (iv) US in correlation with the other imaging modalities (post-US). Postoperative histology, FNB, and long-term follow-up (median, 2.8 years) were taken as composite gold standard. RESULTS: Fifty-eight malignant lesions were identified in 34 patients. Forty lesions were located in the neck or upper mediastinum. On receiver operating characteristics (ROC) analysis, 18F-FDG-PET had a limited lesion-based specificity of 59% at a set sensitivity of 90%. Pre-US had poor sensitivity and specificity of 52% and 53%, respectively, increasing to 85% and 94% on post-US, with knowledge of the PET/CT findings (P < 0.05 vs. PET and pre-US). Multimodal imaging changed therapy in 15 out of 51 patients (30%). CONCLUSION: In patients with suspected recurrent DTC, supplemental targeted US in addition to 18F-FDG-PET-CT increases specificity while maintainin sensitivity, as non-malignant FDG uptake in cervical lesions can be confirmed.

A registry-based study of thyroid paraganglioma: histological and genetic characteristics.

The precise diagnosis of thyroid neoplasias will guide surgical management. Primary thyroid paraganglioma has been rarely reported. Data on prevalence, immunohistochemistry (IHC), and molecular genetics in a systematic series of such patients are pending. We performed a multinational population-based study on thyroid paraganglioma and analyzed prevalence, IHC, and molecular genetics. Patients with thyroid paraganglioma were recruited from the European-American-Head-and-Neck-Paraganglioma-Registry. Demographic and clinical data were registered. Histopathology and IHC were re-investigated. All patients with thyroid paraganglioma underwent molecular genetic analyses of the SDHA, SDHB, SDHC, SDHD, SDHAF2, VHL, RET, TMEM127, and MAX genes. Analyses included Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) for detection of large rearrangements. Of 947 registrants, eight candidates were initially identified. After immunohistochemical analyses of these eight subjects, 5 (0.5%) were confirmed to have thyroid paraganglioma. IHC was positive for chromogranin, synaptophysin, and S-100 and negative for calcitonin in all five thyroid paragangliomas, whereas the three excluded candidate tumors stained positive for pan-cytokeratin, a marker excluding endocrine tumors. Germline variants, probably representing mutations, were found in four of the five confirmed thyroid paraganglioma cases, two each in SDHA and SDHB, whereas the excluded cases had no mutations in the tested genes. Thyroid paraganglioma is a finite entity, which must be differentiated from medullary thyroid carcinoma, because medical, surgical, and genetic management for each is different. Notably, approximately 80% of thyroid paragangliomas are associated with germline variants, with implications for additional tumors and a potential risk for the family. As opposed to sporadic tumors, surgical management and extent of resection are different for heritable tumors, each guided by the precise gene involved.

Latencies longer than 3.5 ms after vagus nerve stimulation does not exclude a nonrecurrent inferior laryngeal nerve.

BACKGROUND: It has recently been reported that a signal latency shorter than 3.5 ms after electrical stimulation of the vagus nerve signify a nonrecurrent course of the inferior laryngeal nerve. We present a patient with an ascending nonrecurrent inferior laryngeal nerve. In this patient, the stimulation latency was longer than 3.5 ms. CASE PRESENTATION: A 74-years old female underwent redo surgery due to a right-sided recurrent nodular goitre. The signal latency on electrical stimulation of the vagus nerve at the level of the carotid artery bifurcation was 3.75 ms. Further dissection revealed a nonrecurrent but ascending course of the inferior laryngeal nerve. Caused by the recurrent goitre, the nerve was elongated to about 10 cm resulting in this long latency. CONCLUSION: This case demonstrates that the formerly proposed "3.5 ms rule" for identifying a nonrecurrent course of the inferior laryngeal nerve has exceptions. A longer latency does not necessarily exclude a nonrecurrent laryngeal nerve.

Outcomes of adrenal-sparing surgery or total adrenalectomy in phaeochromocytoma associated with multiple endocrine neoplasia type 2: an international retrospective population-based study.

BACKGROUND: The prevention of medullary thyroid cancer in patients with multiple endocrine neoplasia type 2 syndrome has demonstrated the ability of molecular diagnosis and prophylactic surgery to improve patient outcomes. However, the other major neoplasia associated with multiple endocrine neoplasia type 2, phaeochromocytoma, is not as well characterised in terms of occurrence and treatment outcomes. In this study, we aimed to systematically characterise the outcomes of management of phaeochromocytoma associated with multiple endocrine neoplasia type 2. METHODS: This multinational observational retrospective population-based study compiled data on patients with multiple endocrine neoplasia type 2 from 30 academic medical centres across Europe, the Americas, and Asia. Patients were included if they were carriers of germline pathogenic mutations of the RET gene, or were first-degree relatives with histologically proven medullary thyroid cancer and phaeochromocytoma. We gathered clinical information about patients'RET genotype, type of treatment for phaeochromocytoma (ie, unilateral or bilateral operations as adrenalectomy or adrenal-sparing surgery, and as open or endoscopic operations), and postoperative outcomes (adrenal function, malignancy, and death). The type of surgery was decided by each investigator and the timing of surgery was patient driven. The primary aim of our analysis was to compare disease-free survival after either adrenal-sparing surgery or adrenalectomy. FINDINGS: 1210 patients with multiple endocrine neoplasia type 2 were included in our database, 563 of whom had phaeochromocytoma. Treatment was adrenalectomy in 438 (79%) of 552 operated patients, and adrenal-sparing surgery in 114 (21%). Phaeochromocytoma recurrence occurred in four (3%) of 153 of the operated glands after adrenal-sparing surgery after 6-13 years, compared with 11 (2%) of 717 glands operated by adrenalectomy (p=0.57). Postoperative adrenal insufficiency or steroid dependency developed in 292 (86%) of 339 patients with bilateral phaeochromocytoma who underwent surgery. However, 47 (57%) of 82 patients with bilateral phaeochromocytoma who underwent adrenal-sparing surgery did not become steroid dependent. INTERPRETATION: The treatment of multiple endocrine neoplasia type 2-related phaeochromocytoma continues to rely on adrenalectomies with their associated Addisonian-like complications and consequent lifelong dependency on steroids. Adrenal-sparing surgery, a highly successful treatment option in experienced centres, should be the surgical approach of choice to reduce these complications.

Frequent EPAS1/HIF2α exons 9 and 12 mutations in non-familial pheochromocytoma.

Pheochromocytomas are neuroendocrine tumors arising from the adrenal medulla. While heritable mutations are frequently described, less is known about the genetics of sporadic pheochromocytoma. Mutations in genes involved in the cellular hypoxia response have been identified in tumors, and recently EPAS1, encoding HIF2α, has been revealed to be a new gene involved in the pathogenesis of pheochromocytoma and abdominal paraganglioma. The aim of this study was to further characterize EPAS1 alterations in non-familial pheochromocytomas. Tumor DNA from 42 adrenal pheochromocytoma cases with apparently sporadic presentation, without known hereditary mutations in predisposing genes, were analyzed for mutations in EPAS1 by sequencing of exons 9 and 12, which contain the two hydroxylation sites involved in HIF2α degradation, and also exon 2. In addition, the copy number at the EPAS1 locus as well as transcriptome-wide gene expression were studied by DNA and RNA microarray analyses, respectively. We identified six missense EPAS1 mutations, three in exon 9 and three in exon 12, in five of 42 pheochromocytomas (12%). The mutations were both somatic and constitutional, and had no overlap in 11 cases (26%) with somatic mutations in NF1 or RET. One sample had two different EPAS1 mutations, shown by cloning to occur in cis, possibly indicating a novel mechanism of HIF2α stabilization through inactivation of both hydroxylation sites. One of the tumors with an EPAS1 mutation also had a gain in DNA copy number at the EPAS1 locus. All EPAS1-mutated tumors displayed a pseudo-hypoxic gene expression pattern, indicating an oncogenic role of the identified mutations.

High cardiac background activity limits 99mTc-MIBI radioguided surgery in aortopulmonary window parathyroid adenomas.

BACKGROUND: Radioguided surgery using 99m-Technetium-methoxyisobutylisonitrile (99mTc-MIBI) has been recommended for the surgical treatment of mediastinal parathyroid adenomas. However, high myocardial 99mTc-MIBI uptake may limit the feasibility of radioguided surgery in aortopulmonary window parathyroid adenoma. CASE PRESENTATION: Two female patients aged 72 (#1) and 79 years (#2) with primary hyperparathyroidism caused by parathyroid adenomas in the aortopulmonary window were operated by transsternal radioguided surgery. After intravenous injection of 370 MBq 99mTc-MIBI at start of surgery, the maximum radioactive intensity (as counts per second) was measured over several body regions using a gamma probe before and after removal of the parathyroid adenoma. Relative radioactivity was calculated in relation to the measured ex vivo radioactivity of the adenoma, which was set to 1.0. Both patients were cured by uneventful removal of aortopulmonary window parathyroid adenomas of 4400 (#1) and 985 mg (#2). Biochemical cure was documented by intraoperative measurement of parathyroid hormone as well as follow-up examination. Ex vivo radioactivity over the parathyroid adenomas was 196 (#1) and 855 counts per second (#2). Before parathyroidectomy, relative radioactivity over the aortopulmonary window versus the heart was found at 1.3 versus 2.6 (#1) and 1.8 versus 4.8 (#2). After removal of the adenomas, radioactivity within the aortopulmonary window was only slightly reduced. CONCLUSION: High myocardial uptake of 99mTc-MIBI limits the feasibility of radioguided surgery in aortopulmonary parathyroid adenoma.

Timing and extent of thyroid surgery for gene carriers of hereditary C cell disease--a consensus statement of the European Society of Endocrine Surgeons (ESES).

PURPOSE: This "consensus statement" aims to summarise the current evidence-based knowledge as to "timing" and planning the "extent" of thyroid surgery in terms of an optimal balance between the prevention of thyroid malignancy (involving metastasis) and the risks associated with more extended surgery (permanent hypoparathyroidism, permanent paralysis of the recurrent laryngeal nerve). Surgery "in time" is influenced by genetic findings and age. Basal (and stimulated) calcitonin levels may individualise the timing and extent of surgery. MATERIALS AND METHODS: The review of English-language studies addressing the management of REarranged during Transfection proto-oncogene mutation carriers including the time, extent of thyroid surgery and results. Evidence is mostly obtained from well-designed, non-experimental descriptive investigations, such as comparative, correlation and case-control studies (level III) with a grading of recommendation B, or from expert committee reports or opinions and/or the clinical experience of respected authorities (level IV) with a grading of recommendation C, respectively. RESULTS: "Risk level D" includes multiple endocrine neoplasia 2B cases. Thyroidectomy is recommended within the first year of life, preferably as soon as possible, due to the very early transformation of C cell hyperplasia to more aggressive tumours. Calcitonin levels may be less helpful. In patients with codon 634 mutations (risk level C), thyroidectomy between ages 2 and 4 years has been proposed based upon evidence of age-dependent and codon-specific progression of early medullary thyroid cancer. In "risk level B" (codons 609, 611, 618, 620, 630 and 804), tandem mutation (804-778) patients should undergo thyroidectomy before the age of 6 years. "Risk level A" includes patients with mutations in codons 321, 515, 533, 600, 603, 606, 635, 649, 666, 768, 776, 790, 791, 804 (single mutation), 833, 844, 861, 891 or 912. Surgery may be postponed until the age of 10 years. However, postponing surgery and avoiding central (level VI) neck dissection in patients with risk levels A to C are only justified in families with a less aggressive MTC history and in combination with the results of basal (and calcium- or pentagastrin-stimulated) serum calcitonin levels. The moment of transition from C cell hyperplasia to MTC seems to occur when calcitonin levels rise. In patients with normal basal and stimulated calcitonin levels, the chance of micro-MTC increases significantly. CONCLUSIONS: Hereditary C cell disease acts as a model to apply the results of bedside genetic testing, age and calcitonin levels (genotype-age-calcitonin-concept) for the individual timing of thyroid surgery and its extent.