Sequential analysis of cfDNA reveals clonal evolution in neuroblastoma patients receiving ALK targeted therapy.

PURPOSE: The study of cell free DNA (cfDNA) enables sequential analysis of tumor cell-specific genetic alterations in neuroblastoma patients. EXPERIMENTAL DESIGN: Eighteen patients with relapsing neuroblastoma having received Lorlatinib, a 3rd generation ALK inhibitor, were identified (SACHA national registry and/or in the institution). cfDNA was analyzed at relapse for 9 patients, and sequentially for 5 patients (blood/bone marrow plasma) by performing WGS library construction followed by ALK-targeted ddPCR of the hotspot mutations (F1174L, R1275Q, I1170N) (variant allele fraction (VAF) detection limit 0.1%) and WES to evaluate disease burden and clonal evolution, following comparison with tumor/germline WES. RESULTS: Overall response rate to Lorlatinib was 33% (CI 13-59%), with response observed in 6/10 cases without versus 0/8 cases with MYCN amplification (MNA). ALK VAFs correlated with the overall clinical disease status, with a VAF<0.1% in clinical remission, versus higher VAFs (>30%) at progression. Importantly, sequential ALK ddPCR detected relapse earlier than clinical imaging. cfDNA WES revealed new SNVs, not seen in the primary tumor, in all instances of disease progression after Lorlatinib treatment, indicating clonal evolution, including alterations in genes linked to tumor aggressivity (TP53) or novel targets (EGFR). Gene pathway analysis revealed an enrichment for genes targeting cell differentiation in emerging clones, and cell adhesion in persistent clones. Evidence of clonal hematopoiesis could be observed in follow-up samples. CONCLUSION: We demonstrate the clinical utility of combining ALK cfDNA ddPCR for disease monitoring and cfDNA WES for the study of clonal evolution and resistance mechanisms in neuroblastoma patients receiving ALK targeted therapy.

The evidence-based role of catecholaminergic PET tracers in Neuroblastoma. A systematic review and a head-to-head comparison with mIBG scintigraphy.

BACKGROUND: Molecular imaging is pivotal in staging and response assessment of children with neuroblastoma (NB). [123I]-metaiodobenzylguanidine (mIBG) is the standard imaging method; however, it is characterised by low spatial resolution, time-consuming acquisition procedures and difficult interpretation. Many PET catecholaminergic radiotracers have been proposed as a replacement for [123I]-mIBG, however they have not yet made it into clinical practice. We aimed to review the available literature comparing head-to-head [123I]-mIBG with the most common PET catecholaminergic radiopharmaceuticals. METHODS: We searched the PubMed database for studies performing a head-to-head comparison between [123I]-mIBG and PET radiopharmaceuticals including meta-hydroxyephedrine ([11C]C-HED), 18F-18F-3,4-dihydroxyphenylalanine ([18F]DOPA) [124I]mIBG and Meta-[18F]fluorobenzylguanidine ([18F]mFBG). Review articles, preclinical studies, small case series (< 5 subjects), case reports, and articles not in English were excluded. From each study, the following characteristics were extracted: bibliographic information, technical parameters, and the sensitivity of the procedure according to a patient-based analysis (PBA) and a lesion-based analysis (LBA). RESULTS: Ten studies were selected: two regarding [11C]C-HED, four [18F]DOPA, one [124I]mIBG, and three [18F]mFBG. These studies included 181 patients (range 5-46). For the PBA, the superiority of the PET method was reported in two out of ten studies (both using [18F]DOPA). For LBA, PET detected significantly more lesions than scintigraphy in seven out of ten studies. CONCLUSIONS: PET/CT using catecholaminergic tracers shows superior diagnostic performance than mIBG scintigraphy. However, it is still unknown if such superiority can influence clinical decision-making. Nonetheless, the PET examination appears promising for clinical practice as it offers faster image acquisition, less need for sedation, and a single-day examination.

Fine needle aspiration as a diagnostic modality for Warthin tumors identified as fluorodeoxyglucose positron emission tomography/computed tomography-positive.

Limited evidence exists regarding the 2-deoxy-2-[fluorine-18]-fluoro-D-glucose (FDG) avidity of Warthin tumors, the second most common benign parotid gland tumor. This study aims to clarify this aspect by analyzing patients who underwent FDG positron emission tomography/computed tomography (PET/CT) and quantifying tumor standardized uptake values (SUV). Medical records of 29 patients with fine needle aspiration (FNA)-confirmed Warthin tumors who underwent FDG-PET/CT near the diagnosis of Warthin tumor were reviewed. Key parameters included cancer history, cytologic diagnosis of Warthin tumor, maximum SUV on FDG PET/CT, and tumor localization. Among the cohort, 18 males and 11 females (average age: 67.9 years) were included. Most patients had malignant neoplasms (lung, head and neck, breast, others). One patient had synchronous liver cancer. Three individuals had bilateral Warthin tumors, and three had bifocal tumors, resulting in 35 tumors for analysis. Tumors were located in the parotid gland (28) and vicinity (7). SUVmax for the Warthin tumors ranged from 3.6 to 26.8, with an average SUVmax of 10.1. Warthin tumors exhibit significant and variable FDG accumulation, exceeding expectations and mimicking high-grade malignancies. Awareness of this phenomenon is crucial for accurate staging and timely management. In cases of positive FDG PET/CT uptake in periparotid, perimandibular, and upper jugular areas, FNA is recommended to avoid misinterpretation or delays in management.

[18F]FDG PET/CT for predicting triple-negative breast cancer outcomes after neoadjuvant chemotherapy with or without pembrolizumab.

PURPOSE: To determine if pretreatment [18F]FDG PET/CT could contribute to predicting complete pathological complete response (pCR) in patients with early-stage triple-negative breast cancer (TNBC) undergoing neoadjuvant chemotherapy with or without pembrolizumab. METHODS: In this retrospective bicentric study, we included TNBC patients who underwent [18F]FDG PET/CT before neoadjuvant chemotherapy (NAC) or chemo-immunotherapy (NACI) between March 2017 and August 2022. Clinical, biological, and pathological data were collected. Tumor SUVmax and total metabolic tumor volume (TMTV) were measured from the PET images. Cut-off values were determined using ROC curves and a multivariable model was developed using logistic regression to predict pCR. RESULTS: N = 191 patients were included. pCR rates were 53 and 70% in patients treated with NAC (N = 91) and NACI (N = 100), respectively (p < 0.01). In univariable analysis, high Ki67, high tumor SUVmax (> 12.3), and low TMTV (≤ 3.0 cm3) were predictors of pCR in the NAC cohort while tumor staging classification (< T3), BRCA1/2 germline mutation, high tumor SUVmax (> 17.2), and low TMTV (≤ 7.3 cm3) correlated with pCR in the NACI cohort. In multivariable analysis, only high tumor SUVmax (NAC: OR 8.8, p < 0.01; NACI: OR 3.7, p = 0.02) and low TMTV (NAC: OR 6.6, p < 0.01; NACI: OR 3.5, p = 0.03) were independent factors for pCR in both cohorts, albeit at different thresholds. CONCLUSION: High tumor metabolism (SUVmax) and low tumor burden (TMTV) could predict pCR after NAC regardless of the addition of pembrolizumab. Further studies are warranted to validate such findings and determine how these biomarkers could be used to guide neoadjuvant therapy in TNBC patients.

Joint EANM/SIOPE/RAPNO practice guidelines/SNMMI procedure standards for imaging of paediatric gliomas using PET with radiolabelled amino acids and [18F]FDG: version 1.0.

Positron emission tomography (PET) has been widely used in paediatric oncology. 2-Deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is the most commonly used radiopharmaceutical for PET imaging. For oncological brain imaging, different amino acid PET radiopharmaceuticals have been introduced in the last years. The purpose of this document is to provide imaging specialists and clinicians guidelines for indication, acquisition, and interpretation of [18F]FDG and radiolabelled amino acid PET in paediatric patients affected by brain gliomas. There is no high level of evidence for all recommendations suggested in this paper. These recommendations represent instead the consensus opinion of experienced leaders in the field. Further studies are needed to reach evidence-based recommendations for the applications of [18F]FDG and radiolabelled amino acid PET in paediatric neuro-oncology. These recommendations are not intended to be a substitute for national and international legal or regulatory provisions and should be considered in the context of good practice in nuclear medicine. The present guidelines/standards were developed collaboratively by the EANM and SNMMI with the European Society for Paediatric Oncology (SIOPE) Brain Tumour Group and the Response Assessment in Paediatric Neuro-Oncology (RAPNO) working group. They summarize also the views of the Neuroimaging and Oncology and Theranostics Committees of the EANM and reflect recommendations for which the EANM and other societies cannot be held responsible.

NUT carcinoma in children, adolescents and young adults.

BACKGROUND: NUT carcinoma (NC), defined by the presence of the NUTM1 rearrangement, is an aggressive tumour associated with poor prognosis. This rare cancer is underdiagnosed and difficult to treat. OBJECTIVE AND METHODS: The primary objective of this review is to describe the clinical, radiological and laboratory features of NC in young patients. The secondary objective is to propose a consensual strategy for the French very Rare Tumour group (FRACTURE group). RESULTS: NUT-specific antibody immunostaining in cases of undifferentiated or poorly differentiated carcinoma may demonstrate the specific NUT gene rearrangement. NCs are frequently advanced stage at diagnosis and the outcome remains poor despite a global strategy that generally includes conventional combination chemotherapy with wide local therapy (surgery, radiotherapy). Chemosensitivity is frequently only transient. CONCLUSION: Recent data have shown that new targeted drugs (histone deacetylase and bromodomain and extra-terminal protein inhibitors) are promising, but their role has yet to be evaluated in NC. Centralized data review is necessary to improve our knowledge of paediatric NC. We propose a multimodal strategy based on published data and their personal experience.

PET metabolic tumor volume as a new prognostic factor in childhood rhabdomyosarcoma.

PURPOSE: Childhood RMS is a rare malignant disease in which evaluation of tumour spread at diagnosis is essential for therapeutic management. F-18 FDG-PET imaging is currently used for initial RMS disease staging. MATERIALS AND METHODS: This multicentre retrospective study in six French university hospitals was designed to analyse the prognostic accuracy of MTV at diagnosis for patients with RMS between 1 January 2007 and 31 October 2017, for overall (OS) and progression-free survival (PFS). MTV was defined as the sum of the primitive tumour and the largest metastasis, where relevant, with a 40% threshold of the primary tumour SUVmax. Additional aims were to define the prognostic value of SUVmax, SUVpeak, and bone lysis at diagnosis. RESULTS: Participants were 101 patients with a median age of 7.4 years (IQR [4.0-12.5], 62 boys), with localized disease (35 cases), regional nodal spread (43 cases), or distant metastases (23). 44 patients had alveolar subtypes. In a univariate analysis, a MTV greater than 200 cm3 was associated with OS (HR = 3.47 [1.79;6.74], p<0.001) and PFS (HR = 3.03 [1.51;6.07], p = 0.002). SUVmax, SUVpeak, and bone lysis also influenced OS (respectively p = 0.005, p = 0.004 and p = 0.007) and PFS (p = 0.029, p = 0.019 and p = 0.015). In a multivariate analysis, a MTV greater than 200 cm3 was associated with OS (HR = 2.642 [1.272;5.486], p = 0.009) and PFS (HR = 2.707 [1.322;5.547], p = 0.006) after adjustment for confounding factors, including SUVmax, SUVpeak, and bone lysis. CONCLUSION: A metabolic tumor volume greater than 200 cm3, SUVmax, SUVpeak, and bone lysis in the pre-treatment assessment were unfavourable for outcome.

Tumor Thrombus on 18F-FDG PET/CT in Stage IV Plasmablastic Lymphoma.

ABSTRACT: A 71-year-old woman with a history of back pain and recent weight loss presented to the emergency department with hematuria. A CT scan was performed and showed left retroperitoneal mass with left renal vein thrombus extended to the vena cava. Tumor biopsy revealed plasmablastic lymphoma. Staging with 18F-FDG PET/CT scan was performed and revealed pulmonary, hepatic, and left supraclavicular lymph node extension. The left retroperitoneal mass showed intense FDG uptake and was associated with widespread tumor thrombus in the peripheral abdominal veins. Differentiating tumor thrombus from bland thrombosis has a significant impact on patient's management.

Fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT) for the detection of bone, lung, and lymph node metastases in rhabdomyosarcoma.

BACKGROUND: Rhabdomyosarcoma (RMS) is the most common paediatric soft-tissue sarcoma and can emerge throughout the whole body. For patients with newly diagnosed RMS, prognosis for survival depends on multiple factors such as histology, tumour site, and extent of the disease. Patients with metastatic disease at diagnosis have impaired prognosis compared to those with localised disease. Appropriate staging at diagnosis therefore plays an important role in choosing the right treatment regimen for an individual patient. Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is a functional molecular imaging technique that uses the increased glycolysis of cancer cells to visualise both structural information and metabolic activity. 18F-FDG-PET combined with computed tomography (CT) could help to accurately stage the extent of disease in patients with newly diagnosed RMS. In this review we aimed to evaluate whether 18F-FDG-PET could replace other imaging modalities for the staging of distant metastases in RMS. OBJECTIVES: To determine the diagnostic accuracy of 18F-FDG-PET/CT imaging for the detection of bone, lung, and lymph node metastases in RMS patients at first diagnosis. SEARCH METHODS: We searched MEDLINE in PubMed (from 1966 to 23 December 2020) and Embase in Ovid (from 1980 to 23 December 2020) for potentially relevant studies. We also checked the reference lists of relevant studies and review articles; scanned conference proceedings; and contacted the authors of included studies and other experts in the field of RMS for information about any ongoing or unpublished studies. We did not impose any language restrictions. SELECTION CRITERIA: We included cross-sectional studies involving patients with newly diagnosed proven RMS, either prospective or retrospective, if they reported the diagnostic accuracy of 18F-FDG-PET/CT in diagnosing lymph node involvement or bone metastases or lung metastases or a combination of these metastases. We included studies that compared the results of the 18F-FDG-PET/CT imaging with those of histology or with evaluation by a multidisciplinary tumour board as reference standard. DATA COLLECTION AND ANALYSIS: Two review authors independently performed study selection, data extraction, and methodological quality assessement according to Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). We analysed data for the three outcomes (nodal involvement and lung and bone metastases) separately. We used data from the 2 × 2 tables (consisting of true positives, false positives, true negatives, and false negatives) to calculate sensitivity and specificity in each study and corresponding 95% confidence intervals. We did not consider a formal meta-analysis to be relevant because of the small number of studies and substantial heterogeneity between studies. MAIN RESULTS: Two studies met our inclusion criteria. The diagnostic accuracy of 18F-FDG-PET/CT was reported in both studies, which included a total of 36 participants. We considered both studies to be at high risk of bias for the domain reference standard. We considered one study to be at high risk of bias for the domain index test and flow and timing. Sensitivity and specificity of 18F-FDG-PET/CT for the detection of bone metastases was 100% in both studies (95% confidence interval (CI) for sensitivity was 29% to 100% in study one and 40% to 100% in study two; 95% CI for specificity was 83% to 100% in study one and 66% to 100% in study two). The reported sensitivity of 18F-FDG-PET/CT for the detection of lung metastases was not calculated since only two participants in study two showed lung metastases, of which one was detected by 18F-FDG-PET/CT. Reported specificity was 96% in study one (95% CI 78% to 100%) and 100% (95% CI 72% to 100%) in study two. The reported sensitivity for the detection of nodal involvement was 100% (95% CI 63% to 100% in study one and 40% to 100% in study two); the reported specificity was 100% (95% CI 78% to 100%) in study one and 89% (95% CI 52% to 100%) in study two. AUTHORS' CONCLUSIONS: The diagnostic accuracy of 18F-FDG-PET/CT for the detection of bone, lung, and lymph node metastases was reported in only two studies including a total of only 36 participants with newly diagnosed RMS. Because of the small number of studies (and participants), there is currently insufficient evidence to reliably determine the diagnostic accuracy of 18F-FDG-PET/CT in the detection of distant metastases. Larger series evaluating the diagnostic accuracy of 18F-FDG-PET/CT for the detection of metastases in patients with RMS are necessary.

Role of 18F-FDG-PET/CT in the staging of metastatic rhabdomyosarcoma: a report from the European paediatric Soft tissue sarcoma Study Group.

BACKGROUND: Initial staging of rhabdomyosarcoma is crucial for prognosis and to tailor the treatment. The standard radiology workup (SRW) includes magnetic resonance imaging, chest computed tomography (CT) and bone scintigraphy, but 18 Fluorine-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) (18F-FDG-PET/CT (PET-CT)) use is increasing. The aim of this study was to evaluate the impact of PET-CT in the initial staging of patients with metastatic rhabdomyosarcoma enrolled in the European protocol MTS2008. METHODS: Two authors retrospectively reviewed the SRW and PET-CT reports comparing the number and sites of metastases detected. For bone marrow involvement, PET-CT and bone marrow aspirates/biopsies were compared. RESULTS: Among 263 metastatic patients enrolled from October 2008 to December 2016, 121 had PET-CT performed at diagnosis, and for 118 of 121 patients, both PET-CT and radiological reports were available for review. PET-CT showed higher sensitivity than SRW in the ability to detect locoregional (96.2% versus 78.5%, P value = 0.0013) and distant lymph node involvement (94.8% versus 79.3%, P value = 0.0242), but sensitivity was lower for intrathoracic sites (lung 79.6% versus 100%, P value = 0.0025). For bone metastasis, PET-CT was more sensitive than bone scintigraphy (96.4% versus 67.9%, P value = 0.0116). The PET-CT sensitivity and specificity to detect marrow involvement were 91.8% and 93.8%, respectively. The mean number of metastatic sites was 1.94 (range 0-5) with PET-CT and 1.72 (range 0-5) with SRW. In four patients (3.4%), PET-CT changed the staging from localised to metastatic disease. CONCLUSION: PET can identify metastatic disease not evident on SRW in a small number of patients. This is because of its higher ability to recognise lymph node and bone involvement. Chest CT remains essential to detect lesions in intrathoracic sites, which can be performed in a one stop-shot routine examination or on a dedicated chest CT scan. PET-CT could replace bone scintigraphy to study bone involvement.

A Rare Cause of SCC Antigen Elevation: Inverted Sinonasal Papilloma.

ABSTRACT: We report the case of a 68-year-old woman who underwent 18F-FDG PET/CT for squamous cell carcinoma antigen (SCC Ag) elevation in the follow-up of a uterine cervical cancer. The examination showed an FDG-avid mass of the left nasal cavity with left maxillary sinusitis and no other site of abnormal FDG uptake. Surgical resection of the nasal polyp was performed, and pathological examination of the specimen revealed an inverted sinonasal papilloma. SCC Ag returned to normal after surgery. Inverted sinonasal papilloma is a rare cause of SCC Ag elevation, which can be depicted by 18F-FDG PET/CT.

European guideline for imaging in paediatric and adolescent rhabdomyosarcoma - joint statement by the European Paediatric Soft Tissue Sarcoma Study Group, the Cooperative Weichteilsarkom Studiengruppe and the Oncology Task Force of the European Society of Paediatric Radiology.

Appropriate imaging is essential in the treatment of children and adolescents with rhabdomyosarcoma. For adequate stratification and optimal individualised local treatment utilising surgery and radiotherapy, high-quality imaging is crucial. The paediatric radiologist, therefore, is an essential member of the multi-disciplinary team providing clinical care and research. This manuscript presents the European rhabdomyosarcoma imaging guideline, based on the recently developed guideline of the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG) Imaging Committee. This guideline was developed in collaboration between the EpSSG Imaging Committee, the Cooperative Weichteilsarkom Studiengruppe (CWS) Imaging Group, and the Oncology Task Force of the European Society of Paediatric Radiology (ESPR). MRI is recommended, at diagnosis and follow-up, for the evaluation of the primary tumour and its relationship to surrounding tissues, including assessment of neurovascular structures and loco-regional lymphadenopathy. Chest CT along with [F-18]2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET)/CT or PET/MRI are recommended for the detection and evaluation of loco-regional and distant metastatic disease. Guidance on the estimation of treatment response, optimal long-term follow-up, technical imaging settings and standardised reporting are described. This European imaging guideline outlines the recommendations for imaging in children and adolescents with rhabdomyosarcoma, with the aim to harmonise imaging and to advance patient care.

Infantile Rhabdomyosarcomas With VGLL2 Rearrangement Are Not Always an Indolent Disease: A Study of 4 Aggressive Cases With Clinical, Pathologic, Molecular, and Radiologic Findings.

VGLL2-rearranged rhabdomyosarcomas (RMS) are rare low-grade tumors with only favorable outcomes reported to date. We describe 4 patients with VGLL2-rearranged RMS confirmed by molecular studies, who experienced local progression and distant metastases, including 2 with fatal outcomes. Tumors were diagnosed at birth (n=3) or at 12 months of age (n=1), and were all localized at initial diagnosis, but unresectable and therefore managed with chemotherapy and surveillance. Metastatic progression occurred from 1 to 8 years from diagnosis (median, 3.5 y). Three patients experienced multimetastatic spread and one showed an isolated adrenal metastasis. At initial diagnosis, 3 tumors displaying bland morphology were misdiagnosed as fibromatosis or infantile fibrosarcoma and initially managed as such, while 1 was a high-grade sarcoma. At relapse, 3 tumors showed high-grade morphology, while 1 retained a low-grade phenotype. Low-grade primary tumors showed only very focal positivity for desmin, myogenin, and/or MyoD1, while high-grade tumors were heterogenously or diffusely positive. Whole-exome sequencing, performed on primary and relapse samples for 3 patients, showed increased genomic instability and additional genomic alterations (eg, TP53, CDKN2A/B, FGFR4) at relapse, but no recurrent events. RNA sequencing confirmed that high-grade tumors retained VGLL2 fusion transcripts and transcriptomic profiles consistent with VGLL2-rearranged RMS. High-grade samples showed a high expression of genes encoding cell cycle proteins, desmin, and some developmental factors. These 4 cases with distinct medical history imply the importance of complete surgical resection, and suggest that RMS-type chemotherapy should be considered in unresectable cases, given the risk of high-grade transformation. They also emphasize the importance of correct initial diagnosis.

Nasopharyngeal carcinoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations.

Nasopharyngeal carcinoma (NPC) is a rare pediatric tumor. Collaborative studies performed over the last decades showed improved results compared to historical data, but standardized guidelines for diagnosis and management of pediatric NPC are still unavailable. This study presents a European consensus guideline for the diagnosis and treatment of pediatric NPC developed by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT). Main recommendations include induction chemotherapy with cisplatin and 5-flurouracil, concomitant chemoradiotherapy in advanced disease, and to consider maintenance treatment with interferon beta (IFN-ß) for selected high-risk patients. Dose adjustments of radiotherapy based on response to induction chemotherapy may decrease the rates of long-term treatment-related complications that affect most of the survivors.

SNMMI Procedure Standard/EANM Practice Guideline on Pediatric 18F-FDG PET/CT for Oncology 1.0.

PREAMBLEThe Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM) is a professional nonprofit medical association founded in 1985 to facilitate communication worldwide among individuals pursuing clinical and academic excellence in nuclear medicine. SNMMI and EANM members are physicians, technologists, and scientists specializing in the research and practice of nuclear medicine.The SNMMI and EANM will periodically put forth new standards/guidelines for nuclear medicine practice to help advance the science of nuclear medicine and improve service to patients. Existing standards/guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each standard/guideline, representing a policy statement by the SNMMI/EANM, has undergone a thorough consensus process, entailing extensive review. The SNMMI and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging requires particular training and skills, as described in each document. These standards/guidelines are educational tools designed to assist practitioners in providing appropriate and effective nuclear medicine care for patients. These guidelines are consensus documents, and are not inflexible rules or requirements of practice. They are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, the SNMMI and the EANM cautions against the use of these standards/guidelines in litigation in which the clinical decisions of a practitioner are called into question.The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by medical professionals taking into account the unique circumstances of each case. Thus, there is no implication that action differing from what is laid out in the standards/guidelines, standing alone, is below standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the standards/guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the standards/guidelines.The practice of medicine involves not only the science, but also the art of dealing with the prevention, diagnosis, alleviation, and treatment of disease. The variety and complexity of human conditions make it impossible for general guidelines to consistently allow for an accurate diagnosis to be reached or a particular treatment response to be predicted. Therefore, it should be recognized that adherence to these standards/guidelines will not ensure a successful outcome. All that should be expected is that the practitioner follows a reasonable course of action, based on their level of training, the current knowledge, the available resources, and the needs/context of the particular patient being treated.PET and computerized tomography (CT) have been widely used in oncology. 18F-FDG is the most common radiotracer used for PET imaging. The purpose of this document is to provide imaging specialists and clinicians guidelines for recommending, performing, and interpreting 18F-FDG PET/CT in pediatric patients in oncology. There is not a high level of evidence for all recommendations suggested in this paper. These recommendations represent the expert opinions of experienced leaders in this field. Further studies are needed to have evidence-based recommendations for the application of 18F-FDG PET/CT in pediatric oncology. These recommendations should be viewed in the context of good practice of nuclear medicine and are not intended to be a substitute for national and international legal or regulatory provisions.

Esthesioneuroblastoma in children, adolescents and young adults.

The esthesioneuroblastoma (ENB) is characterized as a rare malignant sinonasal tumor of neuroectodermal origin. Its starting point is the olfactory epithelium located in the upper part of the nasal cavities. Different nomenclatures have been proposed, but the most common are "esthesioneuroblastoma" and "olfactory neuroblastoma". ENBs have a bimodal distribution and mainly occur in teenagers, young adults and people aged 50-60. It is a very rare tumor in pediatrics since only around 100 cases have been reported so far. Within ENBs, we can distinguish tumors with different biological behavior ranging from localized forms with slow evolution to aggressive and metastatic forms at onset. In addition, precisely diagnosing undifferentiated tumors and distinguishing them from other etiologies of sinonasal tumors are sometime difficult. Added to its very low incidence, these characteristics make the study of ENB complicated. The standard treatment currently includes broad surgery followed by radiation therapy in localized resectable tumors. Neoadjuvant chemotherapy is indicated in large unresectable tumors and in metastatic forms. However, in certain indications, such as high-grade operable tumors, the role of perioperative chemotherapy remains to be defined. The objective of this analysis is to detail current knowledge regarding ENBs' epidemiological, biological, clinical and radiological characteristics as well as how to manage ENB in young patients.

Prognostic impact of postoperative 123I-metaiodobenzylguanidine scintigraphy: added value of SPECT/CT and semiquantification of the uptake at the surgical site.

BACKGROUND: The aim of this study was to assess the prognostic value of postoperative 123I-MIBG scintigraphy, including systematic SPECT/CT and semiquantification of the uptake at the surgical site, in a prospective series of NB patients. METHODS: Patients operated for neuroblastoma and who had benefited from postoperative 123I-MIBG scintigraphy were prospectively and consecutively included. Completeness of surgery was assessed on operative report. One month postoperative 123I-MIBG scintigraphy included planar acquisition and SPECT/CT. Semi-quantification of the 123I-MIBG SPECT/CT uptake at the surgical site was performed and ratios to reference (liver and mediastinum) areas were calculated. RESULTS: Thirty patients were included between August 2012 and July 2015. Median follow-up was 36 months (range 10-98). Surgery was considered as complete in 23 patients and incomplete in 7 patients. Eight patients (26.7%) presented progressive disease (1 progression and 7 recurrences). Seven patients died (23.3%), all from NB. Six (20%) patients had positive 123I-MIBG scintigraphy (3 on planar acquisitions and 6 on SPECT/CT) and 24 patients had negative 123I-MIBG scintigraphy. Five of the 6 patients (83%) with positive 123I-MIBG scintigraphy presented progressive disease. Ratio of the uptake at the surgical site to mediastinum was strongly and independently correlated with disease-free interval and overall survival (P=0.02 and 0.01 respectively). The amplified MYCN status was also confirmed as correlated with poorer outcomes. CONCLUSIONS: Postoperative 123I-MIBG scintigraphy including SPECT/CT and semiquantification of the uptake at the surgical site appeared to be a valuable prognostic tool in neuroblastoma.

A Case of Sarcoidosis After Lymphoma.

We report the case of a 62-year-old woman with previous history of stage III Hodgkin lymphoma. Routine follow-up CT scan revealed 2 years after end of treatment the appearance of mediastinal nodes, suspected of lymphoma recurrence. An F-FDG PET/CT was performed showing hypermetabolic mediastinal lymph nodes with diffuse symmetric osteomedullar hypermetabolism of pelvis and scapulae. In the hypothesis of either recurrence or multisystemic inflammatory disorder, bone marrow and lymph node biopsies were performed, revealing the presence of noncaseating epithelioid cell granulomas, leading to the diagnosis of multisystemic sarcoidosis. This case illustrates the sarcoidosis-lymphoma syndrome.

18F-Choline PET/CT Imaging for Intracranial Hemangiopericytoma Recurrence.

We report the case of a 50-year-old man, with previous history of grade 3 intracranial hemangiopericytoma with initial complete surgical resection, addressed for local recurrence. Surgical revision performed 18 months after initial surgery allowed only partial resection, leaving residual disease along the optic nerve. Complementary radiotherapy with proton was decided. F-FDG PET/CT and F-choline PET/CT were both performed for treatment planning. F-FDG PET showed no uptake of the residual tumor, whereas F-choline depicted highly metabolic residual disease uptake with excellent delineation of local recurrence. F-choline PET/CT appears as a useful PET tracer for hemagiopericytoma imaging.

Primary and Secondary Breast Angiosarcoma: FDG PET/CT Series.

Breast angiosarcoma is a rare and aggressive tumor. The role of F-FDG PET/CT in breast angiosarcoma is poorly known. We report a series of 13 lesions in 11 patients with histologically proven primary or secondary breast angiosarcoma who underwent FDG PET/CT at the initial assessment in our institution. All breast lesions showed FDG avidity. Visually and statistically, we observed a significant difference of SUVmax uptake foci between primary and secondary breast angiosarcoma (Wilcoxon test P < 0.0046) and a significantly poorer prognosis for high SUVmax than those with low SUVmax (P = 0.049) regardless of primary or secondary origins.