What Do We C in Children With Scurvy? A Case Series Focused on Musculoskeletal Symptoms.

OBJECTIVES: Vitamin C deficiency in children commonly presents with musculoskeletal symptoms such as gait disturbance, refusal to bear weight, and bone or joint pain. We aimed to identify features that could facilitate early diagnosis of scurvy and estimate the cost of care for patients with musculoskeletal symptoms related to scurvy. METHODS: We conducted a retrospective chart review of patients at a single site with diagnostic codes for vitamin C deficiency, ascorbic acid deficiency, or scurvy. Medical records were reviewed to identify characteristics including presenting symptoms, medical history, and diagnostic workup. The Pediatric Health Information System was used to estimate diagnostic and hospitalization costs for each patient. RESULTS: We identified 47 patients with a diagnosis of scurvy, 49% of whom had a neurodevelopmental disorder. Sixteen of the 47 had musculoskeletal symptoms and were the focus of the cost analysis. Three of the 16 had moderate or severe malnutrition, and 3 had overweight or obesity. Six patients presented to an emergency department for care, 11 were managed inpatient, and 3 required critical care. Diagnostic workups included MRI, computed tomography, echocardiogram, endoscopy, lumbar puncture, and/or EEG. Across all patients evaluated, the cost of emergency department utilization, imaging studies, diagnostic procedures, and hospitalization totaled $470 144 (median $14 137 per patient). CONCLUSIONS: Children across the BMI spectrum, particularly those with neurodevelopmental disorders, can develop vitamin C deficiency. Increased awareness of scurvy and its signs and symptoms, particularly musculoskeletal manifestations, may reduce severe disease, limit adverse effects related to unnecessary tests/treatments, and facilitate high-value care.

Imaging of Congenital Malformations of the Brain.

Brain formation is a continuous and complicated process that is historically categorized by the timing of development. The earliest disorders of dorsal induction occur in the first month of gestation and include anencephaly and cephalocele. Disorders of ventral induction occur during the second month of gestation and include the holoprosencephaly and septo-optic dysplasia spectrums. The third and longest timeframe include the disorders of neuronal migration and proliferation (gestational weeks eight-25) and include malformations of cortical development: lissencephaly, polymicrogyria, schizencephaly, gray matter heterotopia, and corpus callosal dysgenesis. This review will highlight the neuroimaging of these malformations.

Bevacizumab in the treatment of radiation injury for children with central nervous system tumors.

PURPOSE: Radiation-induced injury is a well-described toxicity in children receiving radiation therapy for tumors of the central nervous system. Standard therapy has historically consisted primarily of high-dose corticosteroids, which carry significant side effects. Preclinical models suggest that radiation necrosis may be mediated in part through vascular endothelial growth factor (VEGF) overexpression, providing the rationale for use of VEGF inhibitors in the treatment of CNS radiation necrosis. We present the first prospective experience examining the safety, feasibility, neurologic outcomes, and imaging characteristics of bevacizumab therapy for CNS radiation necrosis in children. METHODS: Seven patients between 1 and 25 years of age with neurologic deterioration and MRI findings consistent with radiation injury or necrosis were enrolled on an IRB-approved pilot feasibility study. Patients received bevacizumab at a dose of 10 mg/kg intravenously every 2 weeks for up to 6 total doses. RESULTS: Five patients (83%) were able to wean off corticosteroid therapy during the study period and 4 patients (57%) demonstrated improvement in serial neurologic exams. All patients demonstrated a decrease in T1-weighted post-gadolinium enhancement on MRI, while 5 (71%) showed a decrease in FLAIR signal. Four patients developed a progressive disease of their underlying tumor during bevacizumab therapy. CONCLUSIONS: Our experience lends support to the safety and feasibility of bevacizumab administration for the treatment of radiation necrosis for appropriately selected patients within the pediatric population.

Disseminated Histoplasmosis as an AIDS-Defining Illness Presenting as Fever of Unknown Origin in an 11-Year-Old Female.

A previously healthy 11-year-old female, who emigrated from Central America four years prior, was admitted with eight days of fever, night sweats, and anorexia. Past medical history included severe bronchiolitis, varicella, and hepatitis A as a child. Upon admission, her physical exam was significant for nontender cervical lymphadenopathy, intermittent erythematous papules on the upper extremities, and mild abdominal tenderness. Initial laboratory studies revealed leukopenia, anemia, elevated inflammatory markers, and antibodies to HIV-1 in the patient's serum and cerebrospinal fluid. Computed tomography scan was remarkable for many small nodules throughout the lungs and widespread lymphadenopathy. Additional testing confirmed the diagnosis of HIV/AIDS with a CD4 count of 52 cells/mm3, complicated by disseminated histoplasmosis. This case is significant because it represents a late presentation of vertically transmitted HIV with disseminated histoplasmosis in a nonendemic region as the AIDS-defining illness. This highlights the importance of maintaining a broad differential for opportunistic infections, especially among those who have spent a significant amount of time in a country where unusual pathogens may be more common. This case also considers the utility of antigen testing as a sensitive diagnostic test in immunocompromised patients.

Brain imaging in classic nonketotic hyperglycinemia: Quantitative analysis and relation to phenotype.

Patients with severe nonketotic hyperglycinemia (NKH) have absent psychomotor development and intractable epilepsy, whereas attenuated patients have variable psychomotor development and absent or treatable epilepsy; differences in brain magnetic resonance imaging (MRI) between phenotypes have not been reported. In a retrospective cross-sectional study, we reviewed 38 MRI studies from 24 molecularly proven NKH patients, and 2 transient NKH patients. Quantitative analyses included corpus callosum size, apparent diffusion coefficient, automated brain volumetric analysis, and glycine/creatine ratio by spectroscopy. All patients age <3 months had restricted diffusion in the posterior limb of the internal capsule, anterior brainstem, posterior tegmental tracts, and cerebellum, not present in transient NKH. In older infants, the pattern evolved and included generalized diffusion restriction in the supratentorial white matter, which quantitatively peaked between 3 and 12 months. No patient had absent corpus callosum or gyral malformation. The corpus callosum was relatively short in severe compared to attenuated phenotypes, and thin in severe cases only. The corpus callosum growth rate differed by severity; age-matched Z-scores of thickness worsened in severe cases only. Cerebral volume was decreased in the hippocampus, globus pallidus, cerebral cortex, thalamus, and cerebellum. Severe patients had greatest glycine/creatine ratios. In this study, no brain malformations were identified. The growth failure of the corpus callosum is worse in severe NKH, whereas the diffusion restriction pattern, reflecting microspongiosis, does not discriminate by phenotypic severity. NKH is therefore a disorder of brain growth best recognized in the corpus callosum, whereas spongiosis is not prognostic.

Moyamoya in a Patient with Smith-Magenis Syndrome.

Occurrence of moyamoya syndrome in a patient with Smith-Magenis syndrome (SMS) has previously been reported once in a 10-year-old Asian female. We report a second case of moyamoya in a patient with SMS, in a now 25-year-old Asian female diagnosed with both conditions as a child. In addition to describing her medical and surgical history, we provide a detailed report of her omental transposition, in which the omental circulation was anastomosed to the superior thyroid artery and external jugular vein. To our knowledge, this is the first report of omental transposition for moyamoya in which omental vessels are anastomosed to vessels in the neck, as well as the second report of moyamoya in a patient with SMS.

Sonography of pediatric blunt scrotal trauma: what the pediatric urologist wants to know.

Pediatric blunt scrotal trauma is most often the consequence of sports injury and presents a diagnostic challenge because swelling and pain make a scrotal physical exam difficult. US with color flow and duplex Doppler is the first-line imaging modality with the goal of accurate and timely diagnosis of injury requiring surgery to preserve fertility and hormonal function. US imaging findings following blunt scrotal trauma include hydrocele, hematocele, testicular hematoma, testicular fracture, testicular rupture, compromised perfusion/testicular torsion and testicular dislocation. Importantly, several of these findings may coexist. Our goal is to present the pertinent intrascrotal anatomy, US imaging findings for each testicular injury, and contemporary management for each, with emphasis on what our pediatric urology colleagues need to know for optimal patient care.

Pediatric Cortical Vein Thrombosis: Frequency and Association With Venous Infarction.

BACKGROUND AND PURPOSE: Cortical vein thrombosis (CVT) is an uncommon site of involvement in cerebral sinovenous thrombosis. Few reports have described pediatric CVT, and none has differentiated its unique attributes. This study assessed the clinical features and radiographic outcome of a cohort of children with cerebral sinovenous thrombosis, comparing those with CVT to those without CVT. METHODS: Children diagnosed with cerebral sinovenous thrombosis were retrospectively reviewed and separated into 2 groups based on the presence or absence of cortical vein involvement. RESULTS: Fifty patients met inclusion criteria, including 12 with CVT. The CVT group was more likely to present with seizure (P=0.0271), altered mental status (P=0.0271), and a family history of clotting disorder (P=0.0477). Acute imaging of the CVT group more commonly demonstrated concurrent superior sagittal sinus thrombosis (P=0.0024), parenchymal hemorrhage (P=0.0141), and restricted diffusion (P<0.0001). At follow-up, the CVT group more commonly showed headache, seizure, and focal neurological deficit (P=0.0449), and venous infarction (P=0.0007). CONCLUSIONS: In our cohort, CVT was significantly associated with seizures at presentation, hemorrhage and restricted diffusion on acute imaging, as well as neurological disability and venous infarction at follow-up. Involvement of cortical veins in cerebral sinovenous thrombosis is associated with an increased risk of infarction and adverse outcome in children.

Atypical pediatric ganglioglioma is common and associated with a less favorable clinical course.

OBJECT Ganglioglioma (GG) is commonly recognized as a low-grade tumor located in the temporal lobe, often presenting with seizures. Most are amenable to complete resection and are associated with excellent oncological outcome. The authors encountered several GGs in various locations, which seem to have a less favorable clinical course than GGs in the temporal lobe. METHODS The authors performed a single-center retrospective review of all children with a histological diagnosis of GG who were treated at Children's Hospital Colorado between 1997 and 2013. Each tumor was categorized by 2 pediatric neuroradiologists as typical or atypical based on preoperative MRI appearance. Typical lesions were cortically based, within a single cerebral lobe, well-circumscribed, and solid or mixed solid/cystic. The treatment and clinical course of each patient was analyzed. RESULTS Thirty-seven children were identified, with a median age at presentation of 8.2 years and median follow-up of 38.0 months. Eighteen tumors (48.6%) were typical and 19 (51.4%) were atypical. All typical lesions presented with seizures, whereas no atypical lesions did so. Sixteen (88.9%) typical lesions were located in the temporal lobe. In the atypical group, tumor location was variable, including 11 (57.9%) in the brainstem. Death during follow-up was statistically more common in the atypical group (31.6% vs 0%, p = 0.02). Gross-total resection (GTR) was achieved for 15 of 16 typical tumors (93.8%), compared with 3 atypical tumors (15.8%, p < 0.0001). Presentation with seizure or non-brainstem location were each associated with survival (p = 0.02 and 0.004, respectively). The presence of mutation in BRAF exon 15 did not differ between the 2 groups. CONCLUSIONS Pediatric GG with typical imaging features is associated with excellent rates of GTR and overall survival. Atypical GG is commonly encountered, less amenable to GTR, and associated with a worse outcome. This may relate to anatomical or biological characteristics and merits further investigation.

Cavernous Sinus Thrombosis in Children: Imaging Characteristics and Clinical Outcomes.

BACKGROUND AND PURPOSE: Cavernous sinus thrombosis (CST) is a rare life-threatening cerebrovascular disease known to cause carotid artery narrowing (CAN) and arterial ischemic stroke. The imaging features of CST and related complications have been reported in adults, but rarely in children. METHODS: We performed a retrospective review of children with imaging confirmed CST from 2003 to 2014, describing presenting symptoms, imaging findings, and treatment. RESULTS: Ten patients with CST were identified. All had CAN and 6 of 10 developed infarcts. Of 8 patients treated with anticoagulation therapy, 3 developed new infarcts. None required discontinuation of anticoagulation therapy because of bleeding. Visual impairment secondary to infectious neuritis was common. Imaging characteristics include cavernous sinus expansion, filling defects, restricted diffusion, arterial wall enhancement, empyema, superior ophthalmic vein enlargement and thrombosis, orbital cellulitis, and pituitary inflammation. CAN resolved in 60% of cases. Outcomes were mostly good, with a modified Rankin Scale score of ≤1 for 7 of 10 patients at discharge and 1 death. CONCLUSIONS: CAN and infarcts were common in this modest cohort of children with CST. Despite the high incidence of CAN and infarction, outcomes were often favorable. Although this is the largest cohort of childhood CST reported to date, large multicenter cohorts are needed to confirm our findings and determine the preferred therapeutic strategies for childhood CST.

Contribution of Esophagram to the Evaluation of Complicated Pediatric Eosinophilic Esophagitis.

OBJECTIVES: In contrast to peptic strictures, clinically significant strictures in patients with eosinophilic esophagitis (EoE) may be subtle and go unrecognized at the time of endoscopy. We aimed to identify how often stricture was identified by endoscopy as compared with contrast esophagram. METHODS: We retrospectively reviewed esophagram and endoscopy examinations of all of the patients with EoE with esophageal stricture seen at a tertiary care pediatric hospital over a 6-year period who had both procedures completed within a 3-month time frame. Medical charts were reviewed for clinicopathologic information including age, duration of symptoms, histology, and treatment. RESULTS: Twenty-two children with EoE-associated stricture completed both esophagram and endoscopic assessments. Esophageal strictures were identified by esophagram, and not endoscopy, in 55% of these children. Patients with stricture identified at esophagram alone had a shorter duration of symptoms (2.1 years duration vs 5.4 years duration, P = 0.03) than the group identified by endoscopy. Preoperative radiographic identification of a stricture was associated with dilation more often being performed. CONCLUSIONS: Esophagram is a valuable test to assess esophageal anatomy in children with complicated EoE. Esophagram may be able to detect subtle fibrostenosis earlier in the natural history of the disease than endoscopy.

Pediatric lymphangiectasia: an imaging spectrum.

BACKGROUND: Lymphangiectasia is a rarely encountered lymphatic dysplasia characterized by lymphatic dilation without proliferation. Although it can occur anywhere, the most common locations are the central conducting lymphatics and the pulmonary and intestinal lymphatic networks. Recent advances in lymphatic interventions have resulted in an increased reliance on imaging to characterize patterns of disease. OBJECTIVE: To describe the patient populations, underlying conditions, and imaging features of lymphangiectasia encountered at a tertiary pediatric institution over a 10-year period and correlate these with pathology and patient outcomes. MATERIALS AND METHODS: We retrospectively reviewed the pathology database from 2002 to 2012 to identify patients with pathologically or surgically proven lymphangiectasia who had undergone cross-sectional imaging. Medical records were reviewed for patient demographics, underlying conditions, treatment and outcome. RESULTS: Thirteen children were identified, ranging in age from 1 month to 16 years. Five had pulmonary lymphangiectasia, four intestinal and four diffuse involvement. Pulmonary imaging findings include diffuse or segmental interlobular septal thickening, pleural effusions and dilated mediastinal lymphatics. Intestinal imaging findings include focal or diffuse bowel wall thickening with central lymphatic dilation. Diffuse involvement included dilation of the central lymphatics and involvement of more than one organ system. Children with infantile presentation and diffuse pulmonary, intestinal or diffuse lymphatic abnormalities had a high mortality rate. Children with later presentations and segmental involvement demonstrated clinical improvement with occasional regression of disease. Three children with dilated central lymphatics on imaging underwent successful lymphatic duct ligation procedures with improved clinical course. CONCLUSION: Lymphangiectasia is a complex disorder with a spectrum of presentations, imaging appearances, treatments and outcomes. Cross-sectional imaging techniques distinguish segmental involvement of a single system (pulmonary or intestinal) from diffuse disease and may show dilated central conducting lymphatics, which may benefit from interventions such as ligation or occlusion.

Pediatric posterior fossa ganglioglioma: unique MRI features and correlation with BRAF V600E mutation status.

Ganglioglioma (GG) is a rare pediatric brain tumor (1-4 %) with neoplastic glial and neuronal cells. Posterior fossa GGs (PF GGs) occur less frequently than supratentorial GGs (ST GGs). The BRAF V600E mutation has been reported in GGs and carries therapeutic implications. We compare the presenting symptoms, magnetic resonance imaging, BRAF V600E mutation status, treatment, and prognosis in children with ST and PF GGs. The neuro-oncology database at a tertiary care Children's Hospital was retrospectively reviewed from 1995 to 2010 for patients with ST and PF GG. All available imaging was reviewed. Symptoms, BRAF V600E mutation status, treatment, and survival data were collected from the electronic medical record and analyzed. Our series consisted of 11 PF GG and 20 ST GG. Children with PF GG presented with ataxia, cranial nerve deficits and long tract signs whereas the majority with ST GGs presented with seizures. On imaging, PF GGs were infiltrative and expansile solid masses with dorsal predominant "paintbrush" enhancement whereas ST GGs were well circumscribed mixed solid and cystic masses with heterogeneous enhancement. Five of 11 (45%) PF GGs and 6 of 9 (67%) ST GGs expressed the BRAF V600E mutation. No unique imaging features were identified in BRAF V600E mutation positive tumors. The majority of ST GGs were treated with surgery alone, whereas the majority of PF GGs required multimodality therapy. PF GGs had worse progression-free survival and a higher mortality rate compared with ST GGs. Unlike ST GGs, PF GGs are expansile, infiltrative, show dorsal predominant "paintbrush" enhancement, are not amenable to gross total resection, and have worse progression-free survival and mortality.

18F-FDG PET/CT evaluation of children and young adults with suspected spinal fusion hardware infection.

BACKGROUND: Evaluation of the child with spinal fusion hardware and concern for infection is challenging because of hardware artifact with standard imaging (CT and MRI) and difficult physical examination. Studies using (18)F-FDG PET/CT combine the benefit of functional imaging with anatomical localization. OBJECTIVE: To discuss a case series of children and young adults with spinal fusion hardware and clinical concern for hardware infection. These people underwent FDG PET/CT imaging to determine the site of infection. MATERIALS AND METHODS: We performed a retrospective review of whole-body FDG PET/CT scans at a tertiary children's hospital from December 2009 to January 2012 in children and young adults with spinal hardware and suspected hardware infection. The PET/CT scan findings were correlated with pertinent clinical information including laboratory values of inflammatory markers, postoperative notes and pathology results to evaluate the diagnostic accuracy of FDG PET/CT. An exempt status for this retrospective review was approved by the Institution Review Board. RESULTS: Twenty-five FDG PET/CT scans were performed in 20 patients. Spinal fusion hardware infection was confirmed surgically and pathologically in six patients. The most common FDG PET/CT finding in patients with hardware infection was increased FDG uptake in the soft tissue and bone immediately adjacent to the posterior spinal fusion rods at multiple contiguous vertebral levels. Noninfectious hardware complications were diagnosed in ten patients and proved surgically in four. Alternative sources of infection were diagnosed by FDG PET/CT in seven patients (five with pneumonia, one with pyonephrosis and one with superficial wound infections). CONCLUSION: FDG PET/CT is helpful in evaluation of children and young adults with concern for spinal hardware infection. Noninfectious hardware complications and alternative sources of infection, including pneumonia and pyonephrosis, can be diagnosed. FDG PET/CT should be the first-line cross-sectional imaging study in patients with suspected spinal hardware infection. Because pneumonia was diagnosed as often as spinal hardware infection, initial chest radiography should also be performed.

CT imaging features of eosinophilic colitis in children.

BACKGROUND: Eosinophilic colitis (EC) is a gastrointestinal disease of undetermined etiology whose clinical features overlap with those of the inflammatory bowel diseases. To the best of our knowledge, the CT imaging features of EC have not been described in children. OBJECTIVE: To report and analyze the clinical, imaging and histological findings in seven children with EC. MATERIALS AND METHODS: Children with EC were identified in a pediatric pathology database, and those with CT imaging within 2 months of diagnosis were included, totaling seven children. Clinical, imaging and pathological features were reviewed and analyzed. RESULTS: The most common presenting symptoms were abdominal pain, bloody diarrhea and rectal bleeding. EC was characterized as a dense and predominantly eosinophilic inflammatory infiltrate in the lamina propria or epithelium without granulomas. CT scans were abnormal in six children (86%), demonstrating colonic wall thickening, predominantly cecal, in five (71%), mild to moderate terminal ileal thickening in two (29%), and pneumatosis in one (14%). Right colonic involvement was greater than terminal ileal involvement. CONCLUSION: CT imaging findings in children with EC include right colonic wall thickening of variable extent downstream and absent or mild involvement of the terminal ileum. EC should be considered in the differential diagnosis in children presenting with abdominal pain and bloody diarrhea.

Distinctive pattern of restricted diffusion in a neonate with molybdenum cofactor deficiency.

We present a neonate with molybdenum cofactor deficiency imaged at presentation during the first month of life and at 5 months with diffusion-weighted brain MRI. While the imaging features of this disease have previously been reported, this case highlights a distinctive initial pattern of widespread restricted diffusion involving cortex at the depths of sulci. Other case series have published diffusion-weighted images (DWI) with this pattern but never specifically commented on this finding. This distinct DWI pattern also accounts for the configuration of ulegyria frequently described on later imaging. Early recognition of this unique initial DWI pattern could avoid misdiagnosis and better direct counseling and management.

Intrahepatic fat is increased in the neonatal offspring of obese women with gestational diabetes.

OBJECTIVES: To assess precision magnetic resonance imaging in the neonate and determine whether there is an early maternal influence on the pattern of neonatal fat deposition in the offspring of mothers with gestational diabetes mellitus (GDM) and obesity compared with the offspring of normal-weight women. STUDY DESIGN: A total of 25 neonates born to normal weight mothers (n = 13) and to obese mothers with GDM (n = 12) underwent magnetic resonance imaging for the measurement of subcutaneous and intra-abdominal fat and magnetic resonance spectroscopy for the measurement of intrahepatocellular lipid (IHCL) fat at 1-3 weeks of age. RESULTS: Infants born to obese/GDM mothers had a mean 68% increase in IHCL compared with infants born to normal-weight mothers. For all infants, IHCL correlated with maternal prepregnancy body mass index but not with subcutaneous adiposity. CONCLUSION: Deposition of liver fat in the neonate correlates highly with maternal body mass index. This finding may have implications for understanding the developmental origins of childhood nonalcoholic fatty liver disease.

Arteriopathy, D-dimer, and risk of poor neurologic outcome in childhood-onset arterial ischemic stroke.

OBJECTIVE: To assess whether acute findings of cerebral arteriopathy, large infarct, and acutely elevated plasma D-dimer levels are independently prognostic of poor long-term neurologic outcome as measured at ≥ 1 year post-event in children with arterial ischemic stroke (AIS). STUDY DESIGN: Sixty-one patients with childhood-onset (ie, >28 days of life) AIS were enrolled in a single-institution cohort study at Children's Hospital Colorado between February 2006 and June 2011. Data on demographic and diagnostic characteristics, antithrombotic treatments, and outcomes were systematically collected. RESULTS: Cerebral arteriopathy and D-dimer levels >500 ng/mL (a measure of coagulation activation) were identified acutely in 41% and 31% of the cohort, respectively. Anticoagulation was administered in the acute period post-event in 40% of the children, in the subacute period in 43%, and in the chronic period in 28%. When not receiving anticoagulation, patients were routinely treated with aspirin 2-5 mg/kg once daily for a minimum of 1 year. Death, major bleeding (including intracranial hemorrhage), and recurrent AIS were infrequent. The Pediatric Stroke Outcome Measure at 1 year demonstrated poor outcome in 54% of the children. Acute cerebral arteriopathy and elevated D-dimer level were identified as putative prognostic factors for poor outcome; after adjustment for D-dimer, arteriopathy was an independent prognostic indicator (OR, 19.0; 95% CI, 1.6-229.8; P = .02). CONCLUSION: Arteriopathy and coagulation activation are highly prevalent in the acute period of childhood AIS. Although recurrent AIS and intracranial hemorrhage were infrequent in our cohort, one-half of children experienced a poor neurologic outcome at 1 year, the risk of which was increased by acute arteriopathy. Substantiation of these findings in multi-institutional cohort studies is warranted, toward risk stratification in childhood-onset AIS.

Diffuse intrinsic pontine tumors: a study of primitive neuroectodermal tumors versus the more common diffuse intrinsic pontine gliomas.

OBJECT: The diagnosis of diffuse pontine tumors has largely been made on the basis of MRI since the early 1990 s. In cases of tumors considered "typical," as a rule, no biopsy specimen has been obtained, and the tumors have been considered diffuse intrinsic pontine gliomas (DIPGs). There have been sporadic reports that primitive neuroectodermal tumors (PNETs) of the pons may not be distinguishable from the DIPGs by radiological imaging. This study presents 2 cases of diffuse pontine PNETs with molecular evidence that these are indeed PNETs, distinct from DIPGs, thus supporting biopsy of diffuse pontine tumors as a standard of care. METHODS: Biopsy specimens were obtained from 7 diffuse pontine tumors and snap frozen. Two of these 7 tumors were identified on the basis of pathological examination as PNETs. All 7 of the diffuse pontine tumors were analyzed for gene expression using the Affymetrix HG-U133 Plus 2.0 GeneChip microarray. Gene expression was compared with that of supratentorial PNETs, medulloblastomas, and low- and high-grade gliomas outside the brainstem. RESULTS: Unsupervised hierarchical clustering analysis of gene expression demonstrated that pontine PNETs are most closely related to PNETs of the supratentorial region and not with gliomas. They do not cluster with the 5 DIPGs in the study. Thirty-eight genes, including GATA3, are uniquely differentially expressed in pontine PNETs compared with other types of pediatric brain tumors, including DIPGs and other PNETs at a false discovery rate statistical significance of less than 0.05. CONCLUSIONS: The cluster and individual gene expression analyses indicate that pontine PNETs are intrinsically different from DIPGs. The 2 pontine PNET cases cluster with supratentorial PNETs, rather than with DIPGs, suggesting that these tumors should be treated with a PNET regimen, not with DIPG therapy. Since diagnosis by imaging is not reliable and the biology of the tumors is disparate, a biopsy should be performed to enable accurate diagnosis and direct potentially more effective treatments.