Osteosarcoma in Pediatric and Adult Populations: Are Adults Just Big Kids?

Malignant bone tumors are commonly classified as pediatric or adolescent malignancies, and clinical trials for these diseases have generally focused on these populations. Of primary bone cancers, osteosarcoma is among the most common. Osteosarcoma has a bimodal age distribution, with the first peak occurring in patients from 10 to 14 years old, and the second peak occurring in patients older than 65, with about 25% of cases occurring in adults between 20 and 59 years old. Notably, adult osteosarcoma patients have worse outcomes than their pediatric counterparts. It remains unclear whether age itself is a poor prognostic factor, or if inherent differences in tumor biology exist between age groups. Despite these unknowns, current treatment strategies for adults are largely extrapolated from pediatric studies since the majority of clinical trials for osteosarcoma treatments are based on younger patient populations. In light of the different prognoses observed in pediatric and adult osteosarcoma, we summarize the current understanding of the molecular etiology of osteosarcoma and how it may differ between age groups, hypothesizing why adult patients have worse outcomes compared to children.

Consensus recommendations in the management of Ewing sarcoma from the National Ewing Sarcoma Tumor Board.

Ewing sarcoma (ES) is a malignant tumor of bone and soft tissue that most often occurs in adolescents and young adults. Despite an international coordinated approach, several nuances, discrepancies, and debates remain in defining the standard of care for treating ES. In this review, the authors leverage the expertise assembled by formation of the National Ewing Sarcoma Tumor Board, a multi-institution, multidisciplinary virtual tumor board that meets monthly to discuss complicated and challenging cases of ES. This report is focused on select topics that apply to the management of patients with newly diagnosed ES. The specific topics covered include indications for bone marrow aspirate and biopsy for initial evaluation compared with fluorodeoxyglucose-positron emission tomography, the role of interval compressed chemotherapy in patients aged 18 years and older, the role of adding ifosfamide/etoposide to vincristine/doxorubicin/cyclophosphamide for patients with metastatic disease, the data on and role of high-dose chemotherapy with autologous stem cell transplantation, maintenance therapy, and whole-lung irradiation. The data referenced are often limited to subgroup analyses and/or compiled from multiple sources. Although not intended to replace the clinical judgement of treating physicians, the guidelines are intended to provide clarity and recommendations for the upfront management of patients with ES. PLAIN LANGUAGE SUMMARY: Ewing sarcoma is a malignant tumor of bone and soft tissue that most often occurs in adolescents and young adults. For this review, the authors used the experience of the National Ewing Sarcoma Tumor Board, a multi-institution, multidisciplinary virtual tumor board that meets monthly to discuss complicated and challenging cases of Ewing sarcoma. Although not intended to replace the clinical judgement of treating physicians, the guidelines will focus on the development of consensus statements for the upfront management of patients with Ewing sarcoma.

CD43-positive, EWSR1::FLI1 -rearranged Soft Tissue Sarcoma in a Pediatric Patient With History of B-Cell Acute Lymphoblastic Leukemia.

Ewing sarcoma is a small round blue cell tumor typically characterized by an EWSR1 rearrangement and expression of CD99 and NKX2.2, without expression of hematopoietic markers such as CD45. CD43 is an alternative hematopoietic immunohistochemical marker often utilized in the workup of these tumors and its expression typically argues against Ewing sarcoma. We report a 10-year-old with history of B-cell acute lymphoblastic leukemia presenting with an unusual malignant shoulder mass with variable CD43 positivity, but with an EWSR1::FLI1 fusion detected by RNA sequencing. Her challenging workup highlights the utility of next-generation DNA-based and RNA-based sequencing methods in cases with unclear or conflicting immunohistochemical results.

Intraventricular B7-H3 CAR T Cells for Diffuse Intrinsic Pontine Glioma: Preliminary First-in-Human Bioactivity and Safety.

Diffuse intrinsic pontine glioma (DIPG) remains a fatal brainstem tumor demanding innovative therapies. As B7-H3 (CD276) is expressed on central nervous system (CNS) tumors, we designed B7-H3-specific chimeric antigen receptor (CAR) T cells, confirmed their preclinical efficacy, and opened BrainChild-03 (NCT04185038), a first-in-human phase I trial administering repeated locoregional B7-H3 CAR T cells to children with recurrent/refractory CNS tumors and DIPG. Here, we report the results of the first three evaluable patients with DIPG (including two who enrolled after progression), who received 40 infusions with no dose-limiting toxicities. One patient had sustained clinical and radiographic improvement through 12 months on study. Patients exhibited correlative evidence of local immune activation and persistent cerebrospinal fluid (CSF) B7-H3 CAR T cells. Targeted mass spectrometry of CSF biospecimens revealed modulation of B7-H3 and critical immune analytes (CD14, CD163, CSF-1, CXCL13, and VCAM-1). Our data suggest the feasibility of repeated intracranial B7-H3 CAR T-cell dosing and that intracranial delivery may induce local immune activation. SIGNIFICANCE: This is the first report of repeatedly dosed intracranial B7-H3 CAR T cells for patients with DIPG and includes preliminary tolerability, the detection of CAR T cells in the CSF, CSF cytokine elevations supporting locoregional immune activation, and the feasibility of serial mass spectrometry from both serum and CSF. This article is highlighted in the In This Issue feature, p. 1.

Case report of congenital methemoglobinemia: an uncommon cause of neonatal cyanosis.

BACKGROUND: Methemoglobinemia can be an acquired or congenital condition. The acquired form occurs from exposure to oxidative agents. Congenital methemoglobinemia is a rare and potentially life-threatening cause of cyanosis in newborns that can be caused by either cytochrome B5 reductase or hemoglobin variants known as Hemoglobin M. CASE PRESENTATION: A term male infant developed cyanosis and hypoxia shortly after birth after an uncomplicated pregnancy, with oxygen saturations persistently 70-80% despite 1.0 FiO2 and respiratory support of CPAP+ 6 cm H2O. Pre- and post-ductal saturations were equal and remained below 85%. Initial radiographic and echography imaging was normal. Capillary blood gas values were reassuring with normal pH and an elevated pO2. Investigations to rule out hemolysis and end-organ dysfunction were within acceptable range. Given the absence of clear cardiac or pulmonary etiology of persistent cyanosis, hematologic causes such as methemoglobinemia were explored. No family history was available at the time of transfer to our institution. Unconjugated hyperbilirubinemia > 5 mg/dL (442 µmol/L) interfered with laboratory equipment measurement, making accurate methemoglobin levels unattainable despite multiple attempts. Initial treatment with methylene blue or ascorbic acid was considered. However, upon arrival of the presumed biological father, a thorough history revealed an extensive paternal family history of neonatal cyanosis due to a rare mutation resulting in a hemoglobin M variant. Given this new information, hematology recommended supportive care as well as further testing to confirm the diagnosis of congenital methemoglobinopathy. Whole genome sequencing revealed a likely pathogenic variation in hemoglobin. The neonate was discharged home at 2 weeks of age on full oral feeds with 0.25 L/min nasal cannula as respiratory support, with close outpatient follow-up. By 5 weeks of age, he was weaned off respiratory support. CONCLUSION: Congenital methemoglobinemia should be considered in the differential diagnosis for newborns with persistent hypoxemia despite normal imaging and laboratory values. Accurate quantification of methemoglobin concentrations is challenging in neonates due to the presence of other substances that absorb light at similar wavelengths, including HbF, bilirubin, and lipids.

Locoregional infusion of HER2-specific CAR T cells in children and young adults with recurrent or refractory CNS tumors: an interim analysis.

Locoregional delivery of chimeric antigen receptor (CAR) T cells has resulted in objective responses in adults with glioblastoma, but the feasibility and tolerability of this approach is yet to be evaluated for pediatric central nervous system (CNS) tumors. Here we show that engineering of a medium-length CAR spacer enhances the therapeutic efficacy of human erb-b2 receptor tyrosine kinase 2 (HER2)-specific CAR T cells in an orthotopic xenograft medulloblastoma model. We translated these findings into BrainChild-01 ( NCT03500991 ), an ongoing phase 1 clinical trial at Seattle Children's evaluating repetitive locoregional dosing of these HER2-specific CAR T cells to children and young adults with recurrent/refractory CNS tumors, including diffuse midline glioma. Primary objectives are assessing feasibility, safety and tolerability; secondary objectives include assessing CAR T cell distribution and disease response. In the outpatient setting, patients receive infusions via CNS catheter into either the tumor cavity or the ventricular system. The initial three patients experienced no dose-limiting toxicity and exhibited clinical, as well as correlative laboratory, evidence of local CNS immune activation, including high concentrations of CXCL10 and CCL2 in the cerebrospinal fluid. This interim report supports the feasibility of generating HER2-specific CAR T cells for repeated dosing regimens and suggests that their repeated intra-CNS delivery might be well tolerated and activate a localized immune response in pediatric and young adult patients.

Atraumatic Spinal Epidural Hematoma as Initial Presentation of Hemophilia A in an Infant.

ABSTRACT: Hemophilia A is characterized by deficiency of factor VIII. We present a unique, illustrative case of an infant with a short history of neck pain and irritability without neurological deficits who was found to have a spinal epidural hematoma. The subsequent investigation for the etiology, including workup for nonaccidental trauma, led to a diagnosis of severe hemophilia A.

Activating variants in PDGFRB result in a spectrum of disorders responsive to imatinib monotherapy.

More than 50 individuals with activating variants in the receptor tyrosine kinase PDGFRB have been reported, separated based on clinical features into solitary myofibromas, infantile myofibromatosis, Penttinen syndrome with premature aging and osteopenia, Kosaki overgrowth syndrome, and fusiform aneurysms. Despite their descriptions as distinct clinical entities, review of previous reports demonstrates substantial phenotypic overlap. We present a case series of 12 patients with activating variants in PDGFRB and review of the literature. We describe five patients with PDGFRB activating variants whose clinical features overlap multiple diagnostic entities. Seven additional patients from a large family had variable expressivity and late-onset disease, including adult onset features and two individuals with sudden death. Three patients were treated with imatinib and had robust and rapid response, including the first two reported infants with multicentric myofibromas treated with imatinib monotherapy and one with a recurrent p.Val665Ala (Penttinen) variant. Along with previously reported individuals, our cohort suggests infants and young children had few abnormal features, while older individuals had multiple additional features, several of which appeared to worsen with advancing age. Our analysis supports a diagnostic entity of a spectrum disorders due to activating variants in PDGFRB. Differences in reported phenotypes can be dramatic and correlate with advancing age, genotype, and to mosaicism in some individuals.

Clinicopathologic features of infection-related glomerulonephritis with IgA deposits: a French Nationwide study.

BACKGROUND: Infection-related glomerulonephritis with IgA deposits (IRGN-IgA) is a rare disease but it is increasingly reported in the literature. Data regarding epidemiology and outcome are lacking, especially in Europe. We aimed to assess the clinical, pathologic and outcome data of IRGN-IgA. METHODS: Clinical and outcome data from patients from 11 French centers over the 2007-2017 period were collected retrospectively. We reviewed pathologic patterns and immunofluorescence of renal biopsies and evaluated C4d expression in IRGN-IgA. We analyzed the correlation between histological presentation and outcome. RESULTS: Twenty-seven patients (23 men, mean age: 62 ± 15 years) were included. Twenty-one (78%) had Staphylococcus aureus infection and twelve (44%) were diabetic. At the time of biopsy, 95.2% had haematuria, 48.1% had a serum creatinine level of > 4 mg/dL, and 16% had hypocomplementemia. The most common pathologic presentation included mesangial (88.9%) and endocapillary proliferative glomerulonephritis (88.9%) with interstitial fibrosis and tubular atrophy (IF/TA) (85.1%). Diffuse and global glomerular C4d expression was found in 17.8%, mostly in biopsies with acute or subacute patterns, and was associated with a short delay between infection and renal biopsy compared to segmental and focal staining. After median follow-up of 13.2 months, 23.1% died, 46.2% had persistent renal dysfunction and 15.4% reached end-stage renal disease. Renal outcome was correlated to IF/TA severity. CONCLUSIONS: Infection-related glomerulonephritis with IgA deposits is usually associated with Staphylococcus infections and mainly affects adult men. This entity has a poor prognosis which is correlated to interstitial fibrosis and tubular atrophy severity.

Larotrectinib in patients with TRK fusion-positive solid tumours: a pooled analysis of three phase 1/2 clinical trials.

BACKGROUND: The selective TRK inhibitor larotrectinib was approved for paediatric and adult patients with advanced TRK fusion-positive solid tumours based on a primary analysis set of 55 patients. The aim of our analysis was to explore the efficacy and long-term safety of larotrectinib in a larger population of patients with TRK fusion-positive solid tumours. METHODS: Patients were enrolled and treated in a phase 1 adult, a phase 1/2 paediatric, or a phase 2 adolescent and adult trial. Some eligibility criteria differed between these studies. For this pooled analysis, eligible patients were aged 1 month or older, with a locally advanced or metastatic non-CNS primary, TRK fusion-positive solid tumour, who had received standard therapy previously if available. This analysis set includes the 55 patients on which approval of larotrectinib was based. Larotrectinib was administered orally (capsule or liquid formulation), on a continuous 28-day schedule, to adults mostly at a dose of 100 mg twice daily, and to paediatric patients mostly at a dose of 100 mg/m2 (maximum of 100 mg) twice daily. The primary endpoint was objective response as assessed by local investigators in an intention-to-treat analysis. Contributing trials are registered with ClinicalTrials.gov, NCT02122913 (active not recruiting), NCT02637687 (recruiting), and NCT02576431 (recruiting). FINDINGS: Between May 1, 2014, and Feb 19, 2019, 159 patients with TRK fusion-positive cancer were enrolled and treated with larotrectinib. Ages ranged from less than 1 month to 84 years. The proportion of patients with an objective response according to investigator assessment was 121 (79%, 95% CI 72-85) of 153 evaluable patients, with 24 (16%) having complete responses. In a safety population of 260 patients treated regardless of TRK fusion status, the most common grade 3 or 4 larotrectinib-related adverse events were increased alanine aminotransferase (eight [3%] of 260 patients), anaemia (six, 2%), and decreased neutrophil count (five [2%]). The most common larotrectinib-related serious adverse events were increased alanine aminotransferase (two [<1%] of 260 patients), increased aspartate aminotransferase (two [<1%]), and nausea (two [<1%]). No treatment-related deaths occurred. INTERPRETATION: These data confirm that TRK fusions define a unique molecular subgroup of advanced solid tumours for which larotrectinib is highly active. Safety data indicate that long-term administration of larotrectinib is feasible. FUNDING: Bayer and Loxo Oncology.

Expanding the Spectrum of Pediatric NTRK-rearranged Mesenchymal Tumors.

Pediatric mesenchymal tumors harboring variant NTRK fusions (ETV6-negative) are being increasingly described; however, the histologic and clinical features of these variant NTRK tumors and their relationship to classic infantile fibrosarcoma are not well characterized. A better understanding of the clinicopathologic features of these tumors is necessary, and would aid in both early diagnosis and treatment. Therefore, the aim of this study was to characterize a series of pediatric NTRK-rearranged mesenchymal tumors, including classic ETV6-NTRK3 fused tumors and tumors with variant (non-ETV6) NTRK fusions. The clinical features, morphology, immunophenotype, and genetics of 12 classic ETV6-NTRK3 fused infantile fibrosarcoma and 18 variant NTRK-rearranged mesenchymal tumors were evaluated. For both classic and variant groups, the age at diagnosis ranged from birth to 15 years (median, 4 mo) with no sex predilection; the most common sites involved were the extremities and trunk. The rate of local recurrence and metastasis were not significantly different (recurrence rate: 11% classic, 40% variant; metastatic rate: 18% classic, 25% variant). Classic and variant NTRK tumors had an overlapping spectrum of histologic features, containing haphazardly arranged primitive cells in a myxoid background and/or spindle cells in long fascicles. Both groups showed diffuse pan-TRK expression by immunohistochemistry. Otherwise, the immunoprofile was nonspecific, but similar between both groups. No statistical difference was seen in any clinicopathologic feature between the classic ETV6-NTRK3 and variant fusion cohorts. Pediatric NTRK-rearranged mesenchymal tumors with both classic and variant fusions likely represent a spectrum of disease with shared, recognizable cliniopathologic features.

TRK Fusion Cancers in Children: A Clinical Review and Recommendations for Screening.

Chromosomal translocations involving the NTRK1, NTRK2, and NTRK3 genes (TRK fusions), which encode the neurotrophin tyrosine kinase receptors TRKA, TRKB, and TRKC, can result in constitutive activation and aberrant expression of TRK kinase. Certain cancers almost universally harbor TRK fusions, including infantile fibrosarcoma, cellular congenital mesoblastic nephroma, secretory breast cancer, and mammary analog secretory carcinoma of the salivary gland. TRK fusions have also been identified at lower frequencies across a broad range of other pediatric cancers, including undifferentiated sarcomas, gliomas, papillary thyroid cancers, spitzoid neoplasms, inflammatory myofibroblastic tumors, and acute leukemias. Here we review the prevalence and diseases associated with TRK fusions and methods of detection of these fusions in light of the recent development of selective TRK inhibitors, such as larotrectinib, which demonstrated a 75% response rate across children and adults with TRK fusion cancers. We provide recommendations for screening pediatric tumors for the presence of TRK fusions, including the use of immunohistochemistry or fluorescence in situ hybridization for patients with tumors likely to harbor TRK fusions. Further, we recommend next-generation sequencing for tumors that have a relatively low prevalence of TRK fusions, both to identify patients who may benefit from TRK inhibition and to identify other targetable oncogenic drivers that exist in the same tumor types.

Diagnosis, histopathologic correlation and management of hepatoblastoma: What the radiologist needs to know.

Hepatoblastomas are complex pediatric tumors with several pathological subtypes, some of which demonstrate differing imaging features and portend varying prognosis. The radiologist plays a major role not only in the pre-surgical evaluation and baseline staging of the tumor, but also in guiding management and evaluating prognosis based on the PRETEXT (pretreatment extent of tumor) classification. We discuss the pathology, imaging features, and baseline evaluation, with a focus on the role of the radiologist in the management of these tumors.

The use of neoadjuvant larotrectinib in the management of children with locally advanced TRK fusion sarcomas.

BACKGROUND: The highly selective oral tropomyosin receptor kinase (TRK) inhibitor larotrectinib has demonstrated significant activity in adult and pediatric TRK fusion cancers. In the current study, the authors describe the clinical course of children with locally advanced TRK fusion sarcoma who were treated preoperatively with larotrectinib and underwent subsequent surgical resection. METHODS: A total of 24 children were treated on a pediatric phase 1 trial of larotrectinib (ClinicalTrials.gov identifier NCT02637687). Five children who had a documented TRK fusion sarcoma and underwent surgical resection were included in the current analysis. Tumor response (Response Evaluation Criteria In Solid Tumors [RECIST] version 1.1) and surgical outcomes were collected prospectively. RESULTS: A total of 5 patients (median age, 2 years; range, 0.4-12 years) had locally advanced infantile fibrosarcoma (3 patients) or soft-tissue sarcoma (2 patients). Four patients had disease that was refractory to standard therapy. All 5 patients achieved a partial response to larotrectinib by version 1.1 of RECIST and underwent surgical resection after a median of 6 cycles (range, 4-9 cycles) of treatment. Surgical resections were R0 (negative resection margins with no tumor at the inked resection margin) in 3 patients, R1 (microscopic residual tumor at the resection margin) in 1 patient, and R2 (macroscopic residual tumor at the resection margin) in 1 patient. Three patients achieved complete (2 patients) or near-complete (>98% treatment effect; 1 patient) pathologic responses. These patients remained in follow-up and were no longer receiving larotrectinib for a minimum of 7 to 15 months postoperatively. Two patients had viable tumor at the time of surgical resection and positive resection margins and continued to receive adjuvant larotrectinib. No patients experienced postoperative complications or wound healing issues. CONCLUSIONS: Children with locally advanced TRK fusion sarcomas may proceed to surgical resection after treatment with the selective TRK inhibitor larotrectinib, thereby sparing them the potentially significant morbidity noted with current approaches. These results support the evaluation of larotrectinib as presurgical therapy in children with newly diagnosed TRK fusion sarcomas.

Application of genomics to identify therapeutic targets in recurrent pediatric papillary thyroid carcinoma.

Children with papillary thyroid carcinoma (PTC) may relapse despite response to radioactive iodine (RAI). Two children with multiply relapsed PTC underwent whole-genome and transcriptome sequencing. A TPM3-NTRK1 fusion was identified in one tumor, with outlier NTRK1 expression compared to the TCGA thyroid cancer compendium and to Illumina BodyMap normal thyroid. This patient demonstrated resolution of multiple pulmonary nodules without toxicity on oral TRK inhibitor therapy. A RET fusion was identified in the second tumor, another potentially actionable finding. Identification of oncogenic drivers in recurrent pediatric PTC may facilitate targeted therapy while avoiding repeated RAI.

Larotrectinib for paediatric solid tumours harbouring NTRK gene fusions: phase 1 results from a multicentre, open-label, phase 1/2 study.

BACKGROUND: Gene fusions involving NTRK1, NTRK2, or NTRK3 (TRK fusions) are found in a broad range of paediatric and adult malignancies. Larotrectinib, a highly selective small-molecule inhibitor of the TRK kinases, had shown activity in preclinical models and in adults with tumours harbouring TRK fusions. This study aimed to assess the safety of larotrectinib in paediatric patients. METHODS: This multicentre, open-label, phase 1/2 study was done at eight sites in the USA and enrolled infants, children, and adolescents aged 1 month to 21 years with locally advanced or metastatic solid tumours or CNS tumours that had relapsed, progressed, or were non-responsive to available therapies regardless of TRK fusion status; had a Karnofsky (≥16 years of age) or Lansky (<16 years of age) performance status score of 50 or more, adequate organ function, and full recovery from the acute toxic effects of all previous anticancer therapy. Following a protocol amendment on Sept 12, 2016, patients with locally advanced infantile fibrosarcoma who would require disfiguring surgery to achieve a complete surgical resection were also eligible. Patients were enrolled to three dose cohorts according to a rolling six design. Larotrectinib was administered orally (capsule or liquid formulation), twice daily, on a continuous 28-day schedule, in increasing doses adjusted for age and bodyweight. The primary endpoint of the phase 1 dose escalation component was the safety of larotrectinib, including dose-limiting toxicity. All patients who received at least one dose of larotrectinib were included in the safety analyses. Reported here are results of the phase 1 dose escalation cohort. Phase 1 follow-up and phase 2 are ongoing. This trial is registered with ClinicalTrials.gov, number NCT02637687. FINDINGS: Between Dec 21, 2015, and April 13, 2017, 24 patients (n=17 with tumours harbouring TRK fusions, n=7 without a documented TRK fusion) with a median age of 4·5 years (IQR 1·3-13·3) were enrolled to three dose cohorts: cohorts 1 and 2 were assigned doses on the basis of both age and bodyweight predicted by use of SimCyp modelling to achieve an area under the curve equivalent to the adult doses of 100 mg twice daily (cohort 1) and 150 mg twice daily (cohort 2); and cohort 3 was assigned to receive a dose of 100 mg/m2 twice daily (maximum 100 mg per dose), regardless of age, equating to a maximum of 173% of the recommended adult phase 2 dose. Among enrolled patients harbouring TRK fusion-positive cancers, eight (47%) had infantile fibrosarcoma, seven (41%) had other soft tissue sarcomas, and two (12%) had papillary thyroid cancer. Adverse events were predominantly grade 1 or 2 (occurring in 21 [88%] of 24 patients); the most common larotrectinib-related adverse events of all grades were increased alanine and aspartate aminotransferase (ten [42%] of 24 each), leucopenia (five [21%] of 24), decreased neutrophil count (five [21%] of 24), and vomiting (five [21%] of 24). Grade 3 alanine aminotransferase elevation was the only dose-limiting toxicity and occurred in one patient without a TRK fusion and with progressive disease. No grade 4 or 5 treatment-related adverse events were observed. Two larotrectinib-related serious adverse events were observed: grade 3 nausea and grade 3 ejection fraction decrease during the 28-day follow-up after discontinuing larotrectinib and while on anthracyclines. The maximum tolerated dose was not reached, and 100 mg/m2 (maximum of 100 mg per dose) was established as the recommended phase 2 dose. 14 (93%) of 15 patients with TRK fusion-positive cancers achieved an objective response as per Response Evaluation Criteria In Solid Tumors version 1.1; the remaining patient had tumour regression that did not meet the criteria for objective response. None of the seven patients with TRK fusion-negative cancers had an objective response. INTERPRETATION: The TRK inhibitor larotrectinib was well tolerated in paediatric patients and showed encouraging antitumour activity in all patients with TRK fusion-positive tumours. The recommended phase 2 dose was defined as 100mg/m2 (maximum 100 mg per dose) for infants, children, and adolescents, regardless of age. FUNDING: Loxo Oncology Inc.

Ultrasonographic assessment of the internal jugular vein for the estimation of central venous pressure in hemodialysis patients: A preliminary study.

PURPOSE: To investigate a new noninvasive method to assess central venous pressure (CVP) in hemodialysis patients, based on the ultrasonographic measurement of the collapsing point of the internal jugular vein (CVPni). MATERIALS AND METHODS: In this preliminary, noninterventional, single center study, we enrolled 22 dialyzed patients with an indwelling jugular catheter. CVPni was compared to the gold-standard invasive measurement of CVP using the central venous catheter (CVPi). Agreement between CVPi and CVPni was assessed by Bland and Altman Method. Correlation was assessed by linear regression. RESULTS: A strong correlation was observed between CVPi and CVPni (OR = 3.47 [2.96; 4.07], P < .0001). For overloaded patients, the area under the curve for the operating characteristic curve was 0.971 (IC95: 0.915; 1.000). For under-loaded patients, area under the curve was 0.971 (IC95: 0.917; 1.000). The mean bias between intra-individual CVPi and CVPni measures was 0.57 cm H2 O (SD: 3.1 cm H2 O). CONCLUSION: CVPni appears as a noninvasive and reliable technique. Further studies are required to confirm these results and to assess the direct clinical impact of this new method.

Infantile NTRK-associated Mesenchymal Tumors.

Pediatric fibroblastic/myofibroblastic lesions are a relatively common group of tumors with varying morphologies, for which the molecular mechanisms are becoming increasingly well characterized. Congenital infantile fibrosarcoma (CIFS), perhaps the most well studied of these lesions is characterized by a recurrent ETV6-NTRK3 gene fusion. However, a notable subset of locally aggressive congenital/infantile soft tissue lesions with similar morphologic features to CIFS, have not to-date, shown evidence of any canonical molecular aberration. We describe 6 patients with mesenchymal tumors composed of infiltrative fibroblastic/myofibroblastic tumor cells and showing a morphologic spectrum of features much analogous to that previously described in CIFS but without ETV6 fusion transcripts. These tumors lacked a uniform immunoprofile, but showed variable expression of CD34, S100, smooth muscle actin, and CD30. All patients first developed a mass in infancy (≤2 months of age). Using next-generation DNA sequencing, TMP3-NTRK1 fusions were identified in 4 cases, an LMNA-NTRK1 fusion in one case, and a variant EML4-NTRK3 fusion in one case. Similar to infantile fibrosarcoma, these tumors were locally aggressive (with local recurrences if incompletely excised) and rarely metastasized (lung metastases in one patient). Proper identification of these tumors including investigation for NTRK family gene rearrangements is essential for diagnostic accuracy, as well as for clinical management decisions. Given the morbidity associated with radical resection of large soft tissue tumors, children with unresectable, recurrent, and/or metastatic disease may benefit from treatment with NTRK targeted therapies.