Embryonal sarcoma of the liver in pediatric and young adult patients: A report from Children's Oncology Group study ARST0332.

BACKGROUND: Embryonal sarcoma of the liver (ESL) is a rare mesenchymal tumor most common in childhood; the optimal treatment approach is uncertain. The clinical features and outcomes of patients with ESL enrolled in a Children's Oncology Group (COG) clinical trial that evaluated a risk-based strategy for treating soft tissue sarcomas in patients aged <30 years were evaluated. METHODS: This subset analysis included patients with ESL enrolled in COG study ARST0332. Central review of records, pathology, and imaging confirmed the diagnosis, presenting features, and surgery extent and complications. All patients received dose-intensive ifosfamide/doxorubicin chemotherapy, with cycle timing dependent on surgery and radiotherapy. Tumor resection occurred before study entry or after four cycles of chemotherapy; radiotherapy for residual tumor was optional. RESULTS: Thirty-nine eligible/evaluable patients with ESL were analyzed. All tumors were >10 cm in diameter; four were metastatic. Tumor resection was performed upfront in 23 and delayed in 16. Positive surgical margins (n = 6) and intraoperative tumor rupture (n = 6) occurred only in upfront resections. Eight patients received radiotherapy. Estimated 5-year event-free and overall survival were 79% (95% confidence interval [CI], 65%-93%) and 95% (95% CI, 87%-100%), respectively. Positive margins increased the local recurrence risk. One of 13 patients with documented hemorrhagic ascites and/or tumor rupture developed extrahepatic intra-abdominal tumor recurrence. CONCLUSIONS: The treatment strategy used in ARST0332 achieved favorable outcomes for patients with ESL despite a substantial proportion having high-risk disease features. Deferring tumor resection until after neoadjuvant chemotherapy may decrease the risk of intraoperative tumor rupture and improve the likelihood of adequate surgical margins.

INternational Soft Tissue saRcoma ConsorTium (INSTRuCT) consensus statement: Imaging recommendations for the management of rhabdomyosarcoma.

Rhabdomyosarcoma is the most common soft-tissue neoplasm in the pediatric population. The survival of children with rhabdomyosarcoma has only marginally improved over the past 25 years and remains poor for those with metastatic disease. A significant challenge to advances in treatment of rhabdomyosarcoma is the relative rarity of this disease, necessitating years to complete clinical trials. Progress can be accelerated by international cooperation and sharing national experiences. This necessitates agreement on a common language to describe patient cohorts and consensus standards to guide diagnosis, treatment, and response assessment. These goals formed the premise for creating the INternational Soft Tissue saRcoma ConsorTium (INSTRuCT) in 2017. Multidisciplinary members of this consortium have since developed international consensus statements on the diagnosis, treatment, and management of pediatric soft-tissue sarcomas. Herein, members of the INSTRuCT Diagnostic Imaging Working Group present international consensus recommendations for imaging of patients with rhabdomyosarcoma at diagnosis, at staging, and during and after completion of therapy. The intent is to promote a standardized imaging approach to pediatric patients with this malignancy to create more-reliable comparisons of results of clinical trials internationally, thereby accelerating progress in managing rhabdomyosarcoma and improving survival.

Outcomes After Preoperative Chemoradiation With or Without Pazopanib in Non-Rhabdomyosarcoma Soft Tissue Sarcoma: A Report From Children's Oncology Group and NRG Oncology.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.ARST1321 was a phase II study designed to compare the near complete pathologic response rate after preoperative chemoradiation with/without pazopanib in children and adults with intermediate-/high-risk chemotherapy-sensitive body wall/extremity non-Rhabdomyosarcoma Soft Tissue Sarcoma (ClinicalTrials.gov identifier: NCT02180867). Enrollment was stopped early following a predetermined interim analysis that found the rate of near complete pathologic response to be significantly greater with the addition of pazopanib. As a planned secondary aim of the study, the outcome data for this cohort were analyzed. Eight-five eligible patients were randomly assigned to receive (regimen A) or not receive (regimen B) pazopanib in combination with ifosfamide and doxorubicin + preoperative radiotherapy followed by primary resection at week 13 and then further chemotherapy at week 25. As of December 31, 2021, at a median survivor follow-up of 3.3 years (range, 0.1-5.8 years), the 3-year event-free survival for all patients in the intent-to-treat analysis was 52.5% (95% CI, 34.8 to 70.2) for regimen A and 50.6% (95% CI, 32 to 69.2) for regimen B (P = .8677, log-rank test); the 3-year overall survival was 75.7% (95% CI, 59.7 to 91.7) for regimen A and 65.4% (95% CI, 48.1 to 82.7) for regimen B (P = .1919, log-rank test). Although the rate of near complete pathologic response was significantly greater with the addition of pazopanib, outcomes were not statistically significantly different between the two regimens.

Imaging of pediatric extragonadal pelvic soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

The most common pediatric extragonadal pelvic cancers include germ cell tumors, sacrococcygeal teratomas, and rhabdomyosarcomas (arising from the urinary bladder, prostate, paratesticular tissues, vagina, uterus, and perineum). This paper describes the radiological and nuclear medicine features of these entities and provides consensus-based recommendations for the assessment at diagnosis, during, and after treatment.

Lymph node metastases in paediatric and young adult patients with non-rhabdomyosarcoma soft tissue sarcoma (NRSTS): Findings from Children's Oncology Group (COG) study ARST0332.

PURPOSE: The aim of this paper is to better define the clinical features and outcomes of young patients with non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) with regional and distant lymph node (LN) metastases treated in a standardised fashion, we analysed LN involvement in COG study ARST0332, which evaluated a risk-based treatment strategy for young patients with all stages of NRSTS. PATIENTS AND METHODS: Patients <30 years old with newly diagnosed NRSTS and LN metastases enrolled on ARST0332 were studied. Regional LN sampling was required for those with epithelioid sarcoma, clear cell sarcoma or clinically/radiographically enlarged LNs. Tumour features and extent of pre-enrolment resection determined treatment, including chemotherapy, radiotherapy, and delayed surgery. Recommendations for LN metastases included LN dissection at the time of primary tumour resection and dose-adapted radiotherapy based on extent of LN resection. RESULTS: Twenty of 529 eligible and evaluable ARST0332 patients with NRSTS had LN metastases; epithelioid sarcoma had the highest incidence (18%, 5 of 28). Pre-treatment imaging identified LN enlargement in 19 of 20 patients; 1 had no pre-treatment LN imaging. At 6.9 years median follow-up for surviving patients, 5-year overall survival was 85.7% (95% CI: 33.4%, 97.9%) for seven patients with isolated LN metastases and 15.4% (95% CI: 2.5%, 38.8%) for 13 patients with additional extranodal metastases. LN recurrence occurred in only one patient without LNs sampled at initial diagnosis. CONCLUSION: LN metastases occur in about 4% of paediatric/young adult NRSTS, are limited to a few histologic subtypes, and are rare in patients who did not have clinical or imaging evidence of lymphadenopathy, suggesting that biopsies of non-enlarged LNs are not necessary to identify occult involvement. Patients with isolated LN metastases have high 5-year overall survival (∼85%) and should be treated with curative intent. GOV REGISTRY NO: NCT00346164.

Hypoglycemia secondary to insulinoma masking the onset of type 1 diabetes in an adolescent.

Type 1 diabetes and insulinoma can co-occur in pediatric patients and may present with episodes of hypo- and hyperglycemia, significant glycemic variability, and weight gain. Surgical resection leads to development of fulminant diabetes.

Synovial Sarcoma in Children, Adolescents, and Young Adults: A Report From the Children's Oncology Group ARST0332 Study.

PURPOSE: Synovial sarcoma (SS) is the second most common malignant soft tissue tumor in children. ARST0332 evaluated a risk-based treatment strategy for young patients with soft tissue sarcoma designed to limit therapy for low-risk (LR) disease and to test neoadjuvant chemoradiotherapy for unresected higher-risk disease. METHODS: Newly diagnosed patients with SS age < 30 years were assigned to four treatment arms based on disease features: A (surgery only), B (55.8 Gy radiotherapy [RT]), C (ifosfamide and doxorubicin [ID] chemotherapy plus 55.8 Gy RT), and D (neoadjuvant ID and 45 Gy RT, then surgery and RT boost based on margins followed by adjuvant ID). Patients treated in Arms A and B were considered LR, arms C and D without metastases as intermediate-risk (IR), and those with metastases as high-risk (HR). RESULTS: Of the 146 patients with SS enrolled, 138 were eligible and evaluable: LR (46), IR (71), and HR (21). Tumors were 80% extremity, 70% > 5 cm, 70% high-grade, 62% invasive, 95% deep, and 15% metastatic. Treatment was on arm A (29.7%), B (3.6%), C (16.7%), and D (50%). There were no toxic deaths and four unexpected grade 4 adverse events. By risk group, at a median follow-up of 6.8 years, estimated 5-year event-free survival was LR 82%, IR 70%, and HR 8%, and overall survival was LR 98%, IR 89%, and HR 13%. After accounting for the features that defined risk category, none of the other patient or disease characteristics (age, sex, tumor site, tumor invasiveness, and depth) improved the risk stratification model. CONCLUSION: The risk-based treatment strategy used in ARST0332 produced favorable outcomes in patients with nonmetastatic SS relative to historical controls despite using RT less frequently and at lower doses. The outcome for metastatic SS remains unsatisfactory and new therapies are urgently needed.

Local Control For High-Grade Nonrhabdomyosarcoma Soft Tissue Sarcoma Assigned to Radiation Therapy on ARST0332: A Report From the Childrens Oncology Group.

PURPOSE: The ARST0332 trial for pediatric and young adults with nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) used risk-based treatment including primary resection with lower-than-standard radiation doses to optimize local control (LC) while minimizing long-term toxicity in those requiring radiation therapy (RT). RT for high-grade NRSTS was based on extent of resection (R0: negative margins, R1: microscopic margins, R2/U: gross disease/unresectable); those with >5 cm tumors received chemotherapy (CT; ifosfamide/doxorubicin). This analysis evaluates LC for patients assigned to RT and prognostic factors associated with local recurrence (LR). METHODS AND MATERIALS: Patients aged <30 years with high-grade NRSTS received RT (55.8 Gy) for R1 ≤5 cm tumor (arm B); RT (55.8 Gy)/CT for R0/R1 >5 cm tumor (arm C); or neoadjuvant RT (45 Gy)/CT plus delayed surgery, CT, and postoperative boost to 10.8 Gy R0 <5 mm margins/R1 or 19.8 Gy for R2/unresected tumors (arm D). RESULTS: One hundred ninety-three eligible patients had 24 LRs (arm B 1/15 [6.7%], arm C 7/65 [10.8%], arm D 16/113 [14.2%]) at median time to LR of 1.1 years (range, 0.11-5.27). Of 95 eligible for delayed surgery after neoadjuvant therapy, 89 (93.7%) achieved R0/R1 margins. Overall LC after RT were as follows: R0, 106 of 109 (97%); R1, 51 of 60 (85%); and R2/unresectable, 2 of 6 (33%). LR predictors include extent of delayed resection (P <.001), imaging response before delayed surgery (P < .001), histologic subtype (P <.001), and no RT (P = .046). The 5-year event-free survival was significantly lower (P = .0003) for patients unable to undergo R0/R1 resection. CONCLUSIONS: Risk-based treatment for young patients with high-grade NRSTS treated on ARST0332 produced very high LC, particularly after R0 resection (97%), despite lower-than-standard RT doses. Neoadjuvant CT/RT enabled delayed R0/R1 resection in most patients and is preferred over adjuvant therapy due to the lower RT dose delivered.

Pathological response in children and adults with large unresected intermediate-grade or high-grade soft tissue sarcoma receiving preoperative chemoradiotherapy with or without pazopanib (ARST1321): a multicentre, randomised, open-label, phase 2 trial.

BACKGROUND: Outcomes for children and adults with advanced soft tissue sarcoma are poor with traditional therapy. We investigated whether the addition of pazopanib to preoperative chemoradiotherapy would improve pathological near complete response rate compared with chemoradiotherapy alone. METHODS: In this joint Children's Oncology Group and NRG Oncology multicentre, randomised, open-label, phase 2 trial, we enrolled eligible adults (aged ≥18 years) and children (aged between 2 and <18 years) from 57 hospitals in the USA and Canada with unresected, newly diagnosed trunk or extremity chemotherapy-sensitive soft tissue sarcoma, which were larger than 5 cm in diameter and of intermediate or high grade. Eligible patients had Lansky (if aged ≤16 years) or Karnofsky (if aged >16 years) performance status score of at least 70. Patients received ifosfamide (2·5 g/m2 per dose intravenously on days 1-3 with mesna) and doxorubicin (37·5 mg/m2 per dose intravenously on days 1-2) with 45 Gy preoperative radiotherapy, followed by surgical resection at week 13. Patients were randomly assigned (1:1) using a web-based system, in an unmasked manner, to receive oral pazopanib (if patients <18 years 350 mg/m2 once daily; if patients ≥18 years 600 mg once daily) or not (control group), with pazopanib not given immediately before or after surgery at week 13. The study projected 100 randomly assigned patients were needed to show an improvement in the number of participants with a 90% or higher pathological response at week 13 from 40% to 60%. Analysis was done per protocol. This study has completed accrual and is registered with ClinicalTrials.gov, NCT02180867. FINDINGS: Between July 7, 2014, and Oct 1, 2018, 81 eligible patients were enrolled and randomly assigned to the pazopanib group (n=42) or the control group (n=39). At the planned second interim analysis with 42 evaluable patients and a median follow-up of 0·8 years (IQR 0·3-1·6) in the pazopanib group and 1 year (0·3-1·6) in the control group, the number of patients with a 90% pathological response or higher was 14 (58%) of 24 patients in the pazopanib group and four (22%) of 18 patients in the control group, with a between-group difference in the number of 90% or higher pathological response of 36·1% (83·8% CI 16·5-55·8). On the basis of an interim analysis significance level of 0·081 (overall one-sided significance level of 0·20, power of 0·80, and O'Brien-Fleming-type cumulative error spending function), the 83·8% CI for response difference was between 16·5% and 55·8% and thus excluded 0. The improvement in pathological response rate with the addition of pazopanib crossed the predetermined boundary and enrolment was stopped. The most common grade 3-4 adverse events were leukopenia (16 [43%] of 37 patients), neutropenia (15 [41%]), and febrile neutropenia (15 [41%]) in the pazopanib group, and neutropenia (three [9%] of 35 patients) and febrile neutropenia (three [9%]) in the control group. 22 (59%) of 37 patients in the pazopanib group had a pazopanib-related serious adverse event. Paediatric and adult patients had a similar number of grade 3 and 4 toxicity. There were seven deaths (three in the pazopanib group and four in the control group), none of which were treatment related. INTERPRETATION: In this presumed first prospective trial of soft tissue sarcoma spanning nearly the entire age spectrum, adding pazopanib to neoadjuvant chemoradiotherapy improved the rate of pathological near complete response, suggesting that this is a highly active and feasible combination in children and adults with advanced soft tissue sarcoma. The comparison of survival outcomes requires longer follow-up. FUNDING: National Institutes of Health, St Baldrick's Foundation, Seattle Children's Foundation.

A risk-based treatment strategy for non-rhabdomyosarcoma soft-tissue sarcomas in patients younger than 30 years (ARST0332): a Children's Oncology Group prospective study.

BACKGROUND: Tumour grade, tumour size, resection potential, and extent of disease affect outcome in paediatric non-rhabdomyosarcoma soft-tissue sarcoma (NRSTS), but no risk stratification systems exist and the standard of care is poorly defined. We developed a risk stratification system from known prognostic factors and assessed it in the context of risk-adapted therapy for young patients with NRSTS. METHODS: In this prospective study, eligible patients enrolled in 159 hospitals in three countries were younger than 30 years, had a Lansky (patients ≤16 years) or Karnofsky (patients >16 years) performance status score of at least 50, and a new diagnosis of a WHO (2002 criteria) intermediate (rarely metastasising) or malignant soft-tissue tumour (apart from tumour types eligible for other Children's Oncology Group studies and tumours for which the therapy in this trial was deemed inappropriate), malignant peripheral nerve sheath tumour, non-metastatic and grossly resected dermatofibrosarcoma protuberans, undifferentiated embryonal sarcoma of the liver, or unclassified malignant soft-tissue sarcoma. Each patient was assigned to one of three risk groups and one of four treatment groups. Risk groups were: low (non-metastatic R0 or R1 low-grade, or ≤5 cm R1 high-grade tumour); intermediate (non-metastatic R0 or R1 >5 cm high-grade, or unresected tumour of any size or grade); or high (metastatic tumour). The treatment groups were surgery alone, radiotherapy (55·8 Gy), chemoradiotherapy (chemotherapy and 55·8 Gy radiotherapy), and neoadjuvant chemoradiotherapy (chemotherapy and 45 Gy radiotherapy, then surgery and radiotherapy boost based on margins with continued chemotherapy). Chemotherapy included six cycles of ifosfamide 3 g/m2 per dose intravenously on days 1-3 and five cycles of doxorubicin 37·5 mg/m2 per dose intravenously on days 1-2 every 3 weeks with sequence adjusted on the basis of timing of surgery or radiotherapy. The primary outcomes were event-free survival, overall survival, and the pattern of treatment failure. Analysis was done per protocol. This study has been completed and is registered with ClinicalTrials.gov, NCT00346164. FINDINGS: Between Feb 5, 2007, and Feb 10, 2012, 550 eligible patients were enrolled, of whom 21 were treated in the incorrect group and excluded from this analysis. 529 evaluable patients were included in the analysis: low-risk (n=222), intermediate-risk (n=227), high-risk (n=80); surgery alone (n=205), radiotherapy (n=17), chemoradiotherapy (n=111), and neoadjuvant chemoradiotherapy (n=196). At a median follow-up of 6·5 years (IQR 4·9-7·9), 5-year event-free survival and overall survival were: 88·9% (95% CI 84·0-93·8) and 96·2% (93·2-99·2) in the low-risk group; 65·0% (58·2-71·8) and 79·2% (73·4-85·0) in the intermediate-risk group; and 21·2% (11·4-31·1) and 35·5% (23·6-47·4) in the high-risk group, respectively. Risk group predicted event-free survival and overall survival (p<0·0001). No deaths from toxic events during treatment were reported. Nine patients had unexpected grade 4 adverse events (chemoradiotherapy group, n=2; neoadjuvant chemoradiotherapy group, n=7), including three wound complications that required surgery (all in the neoadjuvant chemoradiotherapy group). INTERPRETATION: Pre-treatment clinical features can be used to effectively define treatment failure risk and to stratify young patients with NRSTS for risk-adapted therapy. Most low-risk patients can be cured without adjuvant therapy, thereby avoiding known long-term treatment complications. Survival remains suboptimal for intermediate-risk and high-risk patients and novel therapies are needed. FUNDING: National Institutes of Health, St Baldrick's Foundation, Seattle Children's Foundation, American Lebanese Syrian Associated Charities.

Overview of the clinical and imaging features of the most common non-rhabdomyosarcoma soft-tissue sarcomas.

Non-rhabdomyosarcoma soft-tissue sarcoma (NRSTS) refers to a widely heterogeneous group of extraskeletal mesenchymal neoplasms accounting for approximately 4% of all childhood cancers. This article summarizes the clinical and imaging features of these rare tumors and describes in detail the three most common histological types of NRSTSs encountered in children - synovial sarcoma, malignant peripheral nerve sheath tumor and infantile fibrosarcoma. The author discusses the role of non-cross-sectional and cross-sectional imaging.

Randomized Phase II Trial of Bevacizumab or Temsirolimus in Combination With Chemotherapy for First Relapse Rhabdomyosarcoma: A Report From the Children's Oncology Group.

PURPOSE: The primary aim of this clinical trial was to prioritize bevacizumab or temsirolimus for additional investigation in rhabdomyosarcoma (RMS) when administered in combination with cytotoxic chemotherapy to patients with RMS in first relapse with unfavorable prognosis. PATIENTS AND METHODS: Patients were randomly assigned to receive bevacizumab on day 1 or temsirolimus on days 1, 8, and 15 of each 21-day treatment cycle, together with vinorelbine on days 1 and 8, and cyclophosphamide on day 1 for a maximum of 12 cycles. Local tumor control with surgery and/or radiation therapy was permitted after 6 weeks of treatment. The primary end point was event-free survival (EFS). Radiographic response was assessed at 6 weeks. The study had a phase II selection that was design to detect a 15% difference between the two regimens (α = .2; 1-ß = 0.8; two sided test). RESULTS: Eighty-seven of 100 planned patients were enrolled when the trial was closed after the second interim analysis after 46 events occurred in 68 patients with sufficient follow-up. The O'Brien Fleming boundary at this analysis corresponded to a two-sided P value of .058 with an observed two-sided P value of .003 favoring temsirolimus. The 6-month EFS for the bevacizumab arm was 54.6% (95% CI, 39.8% to 69.3%) and 69.1% (95% CI, 55.1% to 83%) for the temsirolimus arm. Objective response rates were 28% (95% CI, 13.7% to 41.3%) and 47% (95% CI, 31.5% to 63.2%) for the bevacizumab and temsirolimus arms, respectively (P = .12) and, 28% of patients on bevacizumab and 11% on temsirolimus had progressive disease at 6 weeks. CONCLUSION: Patients who received temsirolimus had a superior EFS compared with bevacizumab. Temsirolimus has been selected for additional investigation in newly diagnosed patients with intermediate-risk RMS.

Clinical features and outcomes of young patients with epithelioid sarcoma: an analysis from the Children's Oncology Group and the European paediatric soft tissue Sarcoma Study Group prospective clinical trials.

BACKGROUND: Data on the clinical features, optimal treatment and outcomes of paediatric patients with epithelioid sarcoma (ES) are limited and mostly retrospective. METHODS: A subset analysis of ES patients < 30 years of age enrolled on two international prospective clinical trials conducted between 7/2005 and 11/2015 was performed. Risk-adapted therapy was based on tumour diameter, histologic grade, extent of surgery and presence/absence of metastases and included surgery ± radiotherapy for all patients with the addition of ifosfamide/doxorubicin chemotherapy for intermediate-/high-risk patients. Response to therapy, event-free and overall survival and pattern and predictors of treatment failure were evaluated. RESULTS: Sixty-three ES patients (median age 13.1 years, 52% male) were eligible. Clinical features included the following: 68% extremity, median tumour diameter 3.5 cm, 56% high histologic grade, 14% nodal metastases, 14% distant metastases. Thirty-four low-risk patients underwent surgery (n = 30) or surgery/radiotherapy (n = 4); 16 intermediate-risk and 13 high-risk patients received chemotherapy ± surgery ± radiotherapy. Partial response was observed in 11/22 (50%) patients receiving neoadjuvant therapy. Events were local recurrence (n = 10) and distant recurrence (n = 15); estimated 5-year survival was 86.4%, 63.5% and 0%, respectively, for low-, intermediate- and high-risk patients. Locoregional nodal involvement, invasive tumour, high grade and lesser extent of resection predicted event-free survival in patients without metastases. CONCLUSIONS: Most low-risk ES patients who have undergone an adequate resection fare well without adjuvant therapy. Large tumour size, high histologic grade, tumour invasiveness, inadequate tumour resection and metastatic disease predict poorer outcomes in higher risk ES patients, for whom more effective therapies are needed. CLINICAL TRIAL REGISTRATION: COG ARST0332: ClinicalTrials.gov Identifier NCT00346164, EpSSG NRSTS 2005: European Union Drug Regulating Authorities Clinical Trials No. 2005-001139-31.

Magnetic resonance and computed tomography imaging features of epithelioid sarcoma in children and young adults with pathological and clinical correlation: a report from Children's Oncology Group study ARST0332.

OBJECTIVE: To correlate imaging features of epithelioid sarcoma in children and young adults enrolled in Children's Oncology Group study ARST0332 with clinical and pathological findings. MATERIALS AND METHODS: Fifteen patients (6 males; median age 16.1 years, range 6.5-24.8 years) with epithelioid sarcoma enrolled in ARST0332 had preoperative imaging (MRI, n=10; CT, n=5) that was reviewed by two radiologists who recorded numerous features including presence and percentage of tumor necrosis, presence of surrounding edema, and lymph node involvement. Discrepancies between reviewers were adjudicated by concurrent re-review. We correlated imaging findings with histological assessment of percentage tumor necrosis, proximal- vs. classic-type histology, lymph node involvement and recurrence. RESULTS: Eleven patients (11/15, 73%) had proximal-type histology tumors. Ten of 14 tumors (71%) had imaging evidence of necrosis. Among the nine tumors with imaging and histological estimates of percentage necrosis, agreement was within 30% (in six tumors there was ≤10% difference between pathology and imaging). All 10 tumors imaged with MRI had surrounding edema. Four patients had biopsy-proven nodal involvement; all had necrotic nodes on imaging. There were four false-positives for nodal involvment by imaging. Twelve patients (12/15, 80%) had recurrences (local only, n=1; local and distant, n=1; distant only, n=10). CONCLUSION: Proximal-type histology was prevalent in this young cohort with preoperative imaging. Necrosis is common in primary tumors and involved nodes. There is good agreement between histological and imaging estimates of primary tumor necrosis. Surrounding tumor edema is common in this tumor, which is known to spread along fascial planes.

Imaging of Skeletal Disorders Caused by Fibroblast Growth Factor Receptor Gene Mutations.

Fibroblast growth factors and fibroblast growth factor receptors (FGFRs) play important roles in human axial and craniofacial skeletal development. FGFR1, FGFR2, and FGFR3 are crucial for both chondrogenesis and osteogenesis. Mutations in the genes encoding FGFRs, types 1-3, are responsible for various skeletal dysplasias and craniosynostosis syndromes. Many of these disorders are relatively common in the pediatric population, and diagnosis is often challenging. These skeletal disorders can be classified based on which FGFR is affected. Skeletal disorders caused by type 1 mutations include Pfeiffer syndrome (PS) and osteoglophonic dysplasia, and disorders caused by type 2 mutations include Crouzon syndrome (CS), Apert syndrome (AS), and PS. Disorders caused by type 3 mutations include achondroplasia, hypochondroplasia, thanatophoric dysplasia (TD), severe achondroplasia with developmental delay and acanthosis nigricans, Crouzonodermoskeletal syndrome, and Muenke syndrome. Most of these mutations are inherited in an autosomal dominant fashion and are gain-of-function-type mutations. Imaging plays a key role in the evaluation of these skeletal disorders. Knowledge of the characteristic imaging and clinical findings can help confirm the correct diagnosis and guide the appropriate molecular genetic tests. Some characteristics and clinical findings include premature fusion of cranial sutures and deviated broad thumbs and toes in PS; premature fusion of cranial sutures and syndactyly of the hands and feet in AS; craniosynostosis, ocular proptosis, and absence of hand and foot abnormalities in CS; rhizomelic limb shortening, caudal narrowing of the lumbar interpediculate distance, small and square iliac wings, and trident hands in achondroplasia; and micromelia, bowing of the femora, and platyspondyly in TD. ©RSNA, 2017.

Sonographic Evaluation of Pediatric Thyroid Nodules.

A thyroid nodule detected clinically or incidentally at medical imaging is a common indication for ultrasonography (US) in the adult population. This scenario is less frequently the case in pediatric patients, and the approach to evaluation of thyroid nodules deserves modification in these patients because of the increased probability of malignancy in children, compared with adults. Evaluating a thyroid nodule with US in a systematic way requires familiarity with a number of features that can be assessed and the terms that the radiologist uses in each category. The probability of malignancy is influenced by certain features, and several models have emerged to integrate these details into an overall risk assessment to guide management and biopsy of thyroid nodules. Clinical features of thyroid cancer differ between pediatric and adult patients, and risk factors and certain genetic syndromes portend earlier manifestation of thyroid malignancy. This article provides a review of (a) US features of thyroid nodules with an emphasis on the predictive capacity for malignancy, focused on the pediatric age group when the data exist, (b) clinical information, including risk factors and genetic syndromes pertinent to the pediatric population, and (c) the state of the current literature and controversies in diagnosing and managing pediatric thyroid cancer. ©RSNA, 2017.