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Pleuropulmonary blastoma (PPB) is a rare but aggressive pediatric tumor originates from either lung or pleura. It was recently linked to the DICER I mutation as a part of predisposition syndrome for different type of tumor. It is characterized histologically by a primitive, variably mixed blastomatous and sarcomatous tissue. PPB is classified into four subtypes: cystic (type I and type Ir); cystic and solid (type II); solid (type III). PPB has no characteristic imaging findings. Integrated imaging can help to make a differential diagnosis and to recognize the subtypes in order to set up therapy. An early recognition and differentiation from congenital airway malformations and other benign cysts are very important. The treatment consists in a multimodal therapy including surgery and chemoterapy. We report a case of 3 years old female admitted at our hospital with fever, non productive cough and dyspnea, who was diagnosed with type II PPB.

A 5-month-old boy was evaluated for an unusually large presternal bump present since birth. The ultrasound examination revealed a well-defined soft tissue mass with an oval shape. The lesion demonstrated a regular and well-demarcated outline, with an upper margin that was thinned and inserted into the upper skin plane; the content was anechoic with a small echogenic formation, mobile with changes in the patient's decubitus. The histologic diagnosis was dermoid cyst. Although dermoid cysts are commonly seen in the midline, the midsternal location, found in our patient, is rare. Dermoid cysts can have ultrasonographic features similar to those of other subcutaneous cystic masses. However, if an anechoic cyst with an internal well-circumscribed echogenic ball-like formation is seen within the presternal subcutaneous fat layer, as in our patient, dermoid cyst should be considered in the differential diagnosis of subcutaneous cystic masses.

Background A prospective 2002–2014 study stratified 160 patients by resection extent and histological grade, reporting results in 2016. We re-analyzed the series after a median of 119 months, adding retrospectively patients’ molecular features. Methods Follow-up of all patients was updated. DNA copy number analysis and gene-fusion detection could be completed for 94/160 patients, methylation classification for 68. Results Progression-free survival (PFS) and overall survival (OS) at 5/10 years were 66/58%, and 80/73%. Ten patients had late relapses (range 66–126 mo), surviving after relapse no longer than those relapsing earlier (0–5 y). On multivariable analysis a better PFS was associated with grade II tumor and complete surgery at diagnosis and/or at radiotherapy; female sex and complete resection showed a positive association with OS. Posterior fossa (PF) tumors scoring ≥0.80 on DNA methylation analysis were classified as PFA (n = 41) and PFB (n = 9). PFB patients had better PFS and OS. Eighteen/32 supratentorial tumors were classified as RELA, and 3 as other molecular entities (anaplastic PXA, LGG MYB, HGNET). RELA had no prognostic impact. Patients with 1q gain or cyclin-dependent kinase inhibitor 2A (CDKN2A) loss had worse outcomes, included significantly more patients >3 years old (P = 0.050) and cases of dissemination at relapse (P = 0.007). Conclusions Previously described prognostic factors were confirmed at 10-year follow-up. Late relapses occurred in 6.2% of patients. Specific molecular features may affect outcome: PFB patients had a very good prognosis; 1q gain and CDKN2A loss were associated with dissemination. To draw reliable conclusions, modern ependymoma trials need to combine diagnostics with molecular risk stratification and long-term follow-up.

Children are not simply miniature adults. The evaluation of their gastrointestinal disorders is therefore different from that in full-grown adults and requires a particular clinical/pathologic approach.Different studies have tried to assess the normal eosinophil distribution in the gastrointestinal tract in adults while very few studies have investigated the paediatric population, consequently complicating the pathologist's ability in identifying an abnormal number of eosinophils in this setting of patients.When evaluating gastrointestinal tract biopsies with eosinophilia, eosinophilic count must be considered along with other histological features like eosinophil distribution in the gastrointestinal wall, their degranulation, cryptitis and crypt abscesses, other accompanying inflammatory cells, apoptotic bodies, foreign material or microorganisms; these findings, although rarely specific, may be a useful aid for diagnosis.Reports should not include a diagnosis of primary eosinophilic gastrointestinal disorders (EoGID) if clinical data and test results do not rule out other forms of gastrointestinal eosinophilia. A more descriptive definition like "with eosinophilic pattern" should be favoured over a specific diagnosis of "eosinophilic disorder" in order to avoid potential confusion between different entities.

Medulloblastoma (MB) is an embryonal tumor of the cerebellum constituting ~ 20% of pediatric brain tumors. To date, four MB molecular groups (further stratified in twelve subtypes) have been described. Among them, Groups 3 and Group 4 MB have the poorest prognosis due to their high metastatic potential. Recently, we have reported a metastatic axis driven by Prune1 overexpression in MB Group3 characterized by canonical TGF-β signaling enhancement and epithelial-mesenchymal transition. Here, we have developed a new not toxic pyrido-pyrimidine derivative with the ability to impair Prune-1-driven-axis, thus ameliorating the survival rate of a murine model of metastatic MB Group3 characterized by overexpression of human Prune1 gene in the cerebellum (under the control of MATH1 promoter). Of importance, this small molecule also is showing immunomodulatory functions thus inhibiting the conversion of tumor-infiltrating T lymphocytes (TILs) to immunosuppressive regulatory T cells (Tregs) in vivo via impairing the secretion of inflammatory cytokines from MB cells. Furthermore, this molecule can also act synergistically with the currently used modified-intensity chemotherapy (e.g. in PNET5 use of Vincristine) or potential in the combination with epigenetics drugs (e.g., LSD1/KDM1A inhibitors). Altogether these results are of importance for future targeted therapies of high-risk metastatic MB. Acknowledgments: We thank for funding support: the Italian Association for Cancer Research (AIRC) Grant IG no. 22129 (M.Z.) and Lazio Innova Grant n. 85-2017-14785 (FT; MZ)

Pediatric melanoma is a rare disease especially in children aged younger than 10 years old. Recent estimates report a rise of disease incidence in both adults and children. Diagnostic work-up is challenging in pediatric melanoma, as it displays a wide range of clinical presentations. Immunohistochemical biomarkers have been reported as predictors of malignancy in melanoma, however data specific to pediatric melanoma are poor. Our study aims to contribute to provide evidence of pediatric melanoma clinical features and differential diagnosis in this patient population. We describe our experience with a retrospective case series of pigmented skin lesions including malignant melanoma, atypical spitzoid tumor, and benign nevi in children and adolescents aged less than 16 years. We described the clinical and demographic characteristics of the cohort and evaluated the immunohistochemical expression of the PReferentially expressed Antigen in MElanoma (PRAME) for differential diagnosis of melanoma in children. The series displayed a similar distribution of melanoma between males and females, and the most common site of melanoma onset were the upper and lower limbs. In our cohort, PRAME was negative in most cases. Focal and slight positivity (from 1 to 5% of the neoplastic cells) was observed in four cases (two Spitz nevi and two atypical Spitz tumors). A moderate positivity in 25% of the neoplastic cells was observed in one case of atypical Spitz tumor. Immunohistochemical expression of PRAME might be useful in the differential diagnosis of malignant melanoma.

Purpose Our purpose was to better understand the pathogenesis of seizures associated with angiocentric glioma. Angiocentric glioma is an indolent and rare low-grade glioma. Its typical clinical presentation is with epileptic seizures. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathomechanisms, the increased neurotoxic concentrations of the glutamate has been proposed. Glutamate transporters, pyruvate carboxylase and glutamine synthetase are involved in maintaining the physiological concentration of glutamate in the inter synaptic spaces. Methods We evaluated the immunohistochemical expression of EAAT2 (the most important glutamate transporter), pyruvate carboxylase and glutamine synthetase in 17 angiocentric gliomas. Results EAAT2 was never expressed (0%) in the neoplastic cells in none of the cases studied. Pyruvate carboxylase was expressed in the cytoplasm of the neoplastic cells in 16/17 cases (94 %). Glutamine synthetase was expressed in the cytoplasm of the neoplastic cells in 15/17 cases (88 %). Conclusion The net result of this enzymatic expression, in particular considering the loss of EAAT2, could be an increased glutamate concentration in the synaptic clef, which might increase local network excitability initially involving intratumoral neurons. The observation that the angiocentric glioma-associated epilepsy might be at least in part related to EAAT2 deficiency opens up interesting therapeutic perspectives.

Key Clinical Message We report a young child without a family history of FAP, who promptly underwent APC testing after the histological confirmation of a paraspinal GAF that was not isolated. Our case report reinforces the suggestion advanced by previous authors for an APC analysis in all patients with GAF.

Glial tumors are the leading cause of cancer-related death and morbidity in children. Their diagnosis, mainly based on clinical and histopathological factors, is particularly challenging because of their high molecular heterogeneity. Thus, tumors with identical histotypes could result in variable biological behaviors and prognoses. The PATZ1 gene has been recently shown to be expressed in adult gliomas, including glioblastomas, where it correlates with the proneural subtype and with a better prognosis. Here, we analyzed the expression of PATZ1 in pediatric gliomas, first at mRNA level in a public database, and then at protein level, by immunohistochemistry, in a cohort of 52 glial brain tumors from young patients aged from 6 months to 16 years. As for adult tumors, we show that PATZ1 is enriched in glial tumors compared to the normal brain, where it correlates positively and negatively with a proneural and mesenchymal signature, respectively. Moreover, we show that PATZ1 is expressed at variable levels in our cohort of tumors. Higher expression was detected in high-grade than low-grade gliomas, suggesting a correlation with the malignancy. Among high-grade gliomas, higher levels of PATZ1 have consistently been found to correlate with worse event-free survival. Therefore, our study may imply new diagnostic opportunities for pediatric gliomas.

Simple Summary Melanotic neuroectodermal tumor of infancy (MNTI) is a rare tumor of uncertain origin, morphologically overlapping other rare neoplasms such as pineal anlage tumor (PAT) and a subset of medulloblastomas (i.e., melanotic medulloblastoma). Despite the similarities with MNTI, their possible histogenetic relationship has been traditionally disregarded based on their aggressive behavior and dismal prognosis. The aim of this study was to further characterize the molecular features of MNTI and PAT based on DNA-methylation and copy number variation profiling analysis. We found that MNTI shares a methylation profile with group 3 high-risk medulloblastoma, and potentially with PAT, suggesting a common histogenesis. Most MNTIs in our series lacked copy number variation alterations, whereas their presence in the one PAT deserves further study in larger cohorts to better determine their impact in prognosis and biologic behavior. Abstract MNTI is a rare tumor of indeterminate histogenesis and molecular signature. We performed methylation and copy number variation (CNV) profiles in patients with MNTI (n = 7) and PAT (n = 1) compared to the methylation brain tumor classifier v11b4 (BT-C) and the medulloblastoma (MB) classifier group 3/4 v1.0 (MB3/4-C). The patients’ mean age was 8 months (range: 4–48). The BT-C classified five MNTIs and one PAT (relapse) as class family MB-G3/G4, subclass group 3 (score: >0.9). The remaining two MNTIs and PAT (primary) were classified as class family plexus tumor, subclass pediatric (scores: >0.45). The MB3/4-C classified all MNTIs as high-risk MB-G3, Subtype II (score: >0.45). The primary PAT was classified as subtype III (score: 0.99) and its relapse as subtype II/III. MNTI and PAT clustered close to MB-G3. CNV analysis showed multiple rearrangements in one PAT and two MNTIs. The median follow-up was 54 months (four MNTIs in remission, one PAT died). In conclusion, we demonstrated that MNTI shares a homogenous methylation profile with MB-G3, and possibly with PAT. The role of a multipotent progenitor cell (i.e., early cranial neural crest cell) in their histogenesis and the influence of the anatomical site, tumor microenvironment, and other cytogenetic events in their divergent biologic behavior deserve further investigation.

The exact worldwide incidence of Burkitt’s lymphoma is not known. There are three distinct clinical variants of Burkitt’s lymphoma, each manifesting differences in epidemiology, clinical presentation, morphology, biology and genetic features: the endemic (African), the sporadic (non-endemic), and the immunodeficiency-associated form. In particular, we reported data regarding Burkitt’s lymphoma incidence in the world and across different European countries. Finally, we described clinic-pathological data of 48 Burkitt’s lymphomas occurred in Italy from 2003 to 2013, in 4 different hospitals, two of which located in east side, and the other ones located in the west-coast. Forty Burkitt’s lymphomas occurs in children (age range 3–12), and 8 were adulthood Burkitt’s lymphomas (age range 18–87). In the pediatric group the Male:Female ratio (M:F) was of 4:1, whereas the group of the adult patients has a M:F of 1:1.67. Immunohistochemical detection of Latent Membrane Protein 1 (LMP1) expression and Epstein-Barr virus Encoded RNA (EBER) In Situ Hybridization (ISH) procedures have been performed. Lymphocyte B monoclonal spread has been demonstrated using a Polymerase Chain Reaction (PCR) based method to amplify Fragment Restriction FR1, FR2 and FR3 immunoglobulin heavy chains DNA fragments. Only 38 cases out of 48 were analyzed for LMP-1 showing various percentage of stained cells in 47.4% of the patients. Considering ISH for EBER detection results: – 1 out 2 (50%) adult analyzed cases was positive, with 50% of stained tumor cells (this patient was a 22 years old female, coming from Napoli); – 15 out 24 (62.5%) children analyzed Burkitt’s lymphomas resulted as positive for EBER; – the overall positivity has been observed in 16/26 Burkitt’s lymphomas (61.53%). – Finally, EBV has been detected in children and adult patients, one of them with deregulation of the oncogene c-MYC by chromosomal translocation.

Objective Intraventricular choroid plexus cysts are unusual causes of acute hydrocephalus in children. Radiological diagnosis of intraventricular choroid plexus cysts is difficult because they have very thin walls and fluid contents similar to CSF and can go undetected on routine CT studies. Methods This study reports the authors' experience with 5 patients affected by intraventricular cysts originating from the choroid plexus. All patients experienced acute presentation with rapid neurological deterioration, sometimes associated with hypothalamic dysfunction, and required urgent surgery. In 2 cases the symptoms were intermittent, with spontaneous remission and sudden clinical deteriorations, reflecting an intermittent obstruction of the CSF pathway. Results Radiological diagnosis was difficult in these cases because a nonenhanced CT scan revealed only triventricular hydrocephalus, with slight lateral ventricle asymmetry in all cases. MRI with driven-equilibrium sequences and CT ventriculography (in 1 case) allowed the authors to accurately diagnose the intraventricular cysts that typically occupied the posterior part of the third ventricle, occluding the aqueduct and at least 1 foramen of Monro. The patients were managed by urgent implantation of an external ventricular drain in 1 case (followed by endoscopic surgery, after completing a diagnostic workup) and by urgent endoscopic surgery in 4 cases. Endoscopic surgery allowed the shrinkage and nearcomplete removal of the cysts in all cases. Use of neuronavigation and a laser were indispensable. All procedures were uneventful, resulting in restoration of normal neurological conditions. Long-term follow-up (< 2 years) was available for 2 patients, and no complications or recurrences occurred. Conc lusions This case series emphasizes the necessity of an accurate and precise identification of the possible causes of triventricular hydrocephalus. Endoscopic surgery can be considered the ideal treatment of choroid plexus cysts in children. Objective Intraventricular choroid plexus cysts are unusual causes of acute hydrocephalus in children. Radiological diagnosis of intraventricular choroid plexus cysts is difficult because they have very thin walls and fluid contents similar to CSF and can go undetected on routine CT studies. Methods This study reports the authors' experience with 5 patients affected by intraventricular cysts originating from the choroid plexus. All patients experienced acute presentation with rapid neurological deterioration, sometimes associated with hypothalamic dysfunction, and required urgent surgery. In 2 cases the symptoms were intermittent, with spontaneous remission and sudden clinical deteriorations, reflecting an intermittent obstruction of the CSF pathway. Results Radiological diagnosis was difficult in these cases because a nonenhanced CT scan revealed only triventricular hydrocephalus, with slight lateral ventricle asymmetry in all cases. MRI with driven-equilibrium sequences and CT ventriculography (in 1 case) allowed the authors to accurately diagnose the intraventricular cysts that typically occupied the posterior part of the third ventricle, occluding the aqueduct and at least 1 foramen of Monro. The patients were managed by urgent implantation of an external ventricular drain in 1 case (followed by endoscopic surgery, after completing a diagnostic workup) and by urgent endoscopic surgery in 4 cases. Endoscopic surgery allowed the shrinkage and nearcomplete removal of the cysts in all cases. Use of neuronavigation and a laser were indispensable. All procedures were uneventful, resulting in restoration of normal neurological conditions. Long-term follow-up (< 2 years) was available for 2 patients, and no complications or recurrences occurred. Conc lusions This case series emphasizes the necessity of an accurate and precise identification of the possible causes of triventricular hydrocephalus. Endoscopic surgery can be considered the ideal treatment of choroid plexus cysts in children.

In this study, we investigated the prognostic and predictive value of MGMT promoter methylation and protein expression in 30 pediatric high grade gliomas (pHGG). MGMT promoter methylation was assayed by methylation-specific polymerase chain reaction (MSP), whereas MGMT protein expression was evaluated by immunohistochemistry (IHC). MGMT promoter methylation was observed in 7/24 (30%) cases, whereas MGMT protein overexpression was found in 19/28 (68%) cases with similar distribution in grade III and grade IV gliomas. Median survival of methylated and unmethylated patients was 16 and 8 months, respectively. Moreover, overall survival and progression-free survival showed a trend toward reduction in patients with unmethylation (p = 0.9 and p = 0.7, respectively). For MGMT protein expression, the median survival was 8.5 and 17 months for patients with MGMT overexpression or low expression, respectively. Although these two groups did not show statistically significant differences in terms of overall survival or progression-free survival (p = 0.8 and p = 0.7, respectively), there was a significant correlation between MGMT protein expression and MGMT promoter methylation status (p = 0.01). Our findings indicate that, in pHGG, (a) MGMT promoter methylation is less frequent than in adult malignant gliomas, (b) there is a high correlation between MGMT MSP and MGMT IHC, and (c) as in adults, MGMT status is associated with prognosis, although this observation has to be statistically validated on larger series of patients.

The objective of this study was to evaluate, in a series of 43 pediatric high-grade gliomas (21 anaplastic astrocytoma WHO grade III and 22 glioblastoma WHO grade IV), the prognostic value of histological grading and expression of p53 and YKL-40. Moreover, mutational screening for TP53 and IDH1 was performed in 27 of 43 cases. The prognostic stratification for histological grading showed no difference in overall (OS) and progression-free survival (PFS) between glioblastomas and anaplastic astrocytomas. Overexpression of YKL40 was detected in 25 of 43 (58%) cases, but YKL-40 expression was not prognostic in terms of OS and PFS. p53 protein expression was observed in 13 of 43 (31%) cases but was not prognostic. TP53 mutations were detected in five of 27 (18%) cases (four glioblastomas and one anaplastic astrocytoma). Patients with TP53 mutation had a shorter median OS (9 months) and PFS (8 months) than those without mutations (OS, 17 months; PFS, 16 months), although this trend did not reach statistical significance (p = 0.07). IDH1 mutations were not detected in any of the cases analyzed. Our results suggest that in pediatric high-grade gliomas: (i) histological grading does not have strong prognostic significance, (ii) YKL-40 overexpression is less frequent than adult high-grade gliomas and does not correlate with a more aggressive behavior, (iii) TP53 mutations but not p53 expression may correlate with a more aggressive behavior, and (iv) IDH1 mutations are absent. These observations support the concept that, despite identical histological features, the biology of high-grade gliomas in children differs from that in adults, and therefore different prognostic factors are needed.

Background Diagnosis and proper management of atypical Spitz tumors in pediatric age are still controversial. Objective We sought to investigate the clinicopathological and molecular features of atypical Spitz tumors in patients aged 18 years or younger. Methods We performed a retrospective clinicopathological and fluorescence in situ hybridization study on 50 pediatric atypical Spitz tumors. Results Parameters that were significantly correlated with a diagnosis of atypical Spitz tumors over Spitz nevus included asymmetry, level IV/V, lack of maturation, solid growth, nuclear pleomorphism, high nuclear-cytoplasmic ratio, atypical and deep mitoses, and more than 6 mitoses/mm 2 . In the atypical Spitz tumors group, a significantly higher mitotic rate was observed in prepuberal age ( P = .04). The 4-probe fluorescence in situ hybridization melanoma assay did not discriminate atypical Spitz tumors from Spitz nevi. Heterozygous 9p21 loss was found in 3 of 37 cases and homozygous 9p21 loss in 2 of 37 cases. Only 1 child experienced a fatal outcome, showing genetic abnormalities by melanoma fluorescence in situ hybridization probe and a heterozygous 9p21 deletion. Limitations The limited number of adverse outcomes did not allow the prognostic analysis of single morphologic features. Conclusion Pediatric atypical Spitz tumors are associated with minimal lethal potential. Atypical Spitz tumors require complete excision and careful follow-up while our data do not support any clinical benefit for the sentinel lymph node biopsy procedure and completion lymphadenectomy.

Background High-grade gliomas (HGGs) account for 15% of all pediatric brain tumors and are a leading cause of cancer-related mortality and morbidity. Pediatric HGGs (pHGGs) are histologically indistinguishable from their counterpart in adulthood. However, recent investigations indicate that differences occur at the molecular level, thus suggesting that the molecular path to gliomagenesis in childhood is distinct from that of adults. MicroRNAs (miRNAs) have been identified as key molecules in gene expression regulation, both in development and in cancer. miRNAs have been investigated in adult high-grade gliomas (aHGGs), but scant information is available for pHGGs. Methods We explored the differences in microRNAs between pHGG and aHGG, in both fresh-frozen and paraffin-embedded tissue, by high-throughput miRNA profiling. We also evaluated the biological effects of miR-17-92 cluster silencing on a pHGG cell line. Results Comparison of miRNA expression patterns in formalin versus frozen specimens resulted in high correlation between both types of samples. The analysis of miRNA profiling revealed a specific microRNA pattern in pHGG with an overexpression and a proliferative role of the miR-17-92 cluster. Moreover, we highlighted a possible quenching function of miR-17-92 cluster on its target gene PTEN, together with an activation of tumorigenic signaling such as sonic hedgehog in pHGG. Conclusions Our results suggest that microRNA profiling represents a tool to distinguishing pediatric from adult HGG and that miR-17-92 cluster sustains pHGG.

Primary childhood germ cell tumors (GCTs) represent a rare and heterogeneous group of tumors that varies in histologic differentiation, age of presentation and clinical outcome. In malignant neoplasms, apoptosis is a prognostic marker and a predictive factor of response to therapy. Therefore, the study of the expression and mutation of molecules involved in the regulation of apoptosis could be useful in order to both predict the clinical outcome and design self-tailored therapeutic approaches. We retrospectively analysed tissue samples of 54 childhood GCTs. The expression of p53 and BAX protein was assessed by immunohistochemistry (IHC). Moreover, we investigated the presence of mutations in the BAX and p53 genes SSCP-PCR and direct sequencing. IHC analysis of BAX protein expression showed that 14 out of 54 tumors (26%) had no BAX protein expression, in the remaining 40 patients (74%) the intensity of BAX was low in 20 patients (37%) and high/intermediate in 20 (37%). BAX was mutated in 6 patients. p53 was expressed in 43 patients (79.6%), was not detectable in the remaining 11 (20.4%) and mutated in only 3 patients. p53 mutational status and expression were not correlated to the overall survival (OS). On the other hand, both IHC score and mutations for BAX were correlated to sacrococcygeal primary localization. BAX mutations were inversely correlated with OS (p=0.0419) while BAX IHC intensity was directly correlated with OS (p=0.0376). The stratification for histotype showed a direct correlation between BAX IHC and OS in both immature teratoma (p=0.045) and mixed malignant GCT (p=0.010) while the correlation was lost in mature teratoma (p=0.300). These results indicate that both mutations and BAX protein levels are useful molecular biological markers for prognosis and clinical management of pediatric GCT.

Yersiniosis is a food-borne illness, usually self-limited. Severe clinical courses may occur in chronic conditions, particularly in immunocompromised individuals.1 Here, we report on the case of a 2-year-old girl born to consanguineous parents of Roma descent (a traditionally itinerant ethnic group living mostly in Europe and the Americas, who originate from Northern India), with chronic yersiniosis, recurrent granulomatous lymphadenitis, and episodicneutropenia. Using a targeted next-generation sequencing panel for immunodeficiency genes, a homozygous in-frame deletion in the MYD88 gene was found. MyD88 is a key downstream adapter for most Toll-like receptors (TLRs) and IL-1 receptors (IL-1Rs).2 MYD88 deficiency has been associated with life-threatening and recurrent pyogenic bacterial infections, including invasive pneumococcal disease.

A subset of difficult melanocytic lesions exists with histopathologic features that evade diagnostic consensus from even expert dermatopathologists. Comparative genomic hybridization (CGH) has emerged as a useful diagnostic tool to categorize these lesions, by identifying known chromosomal aberrations in malignant melanoma the lack thereof in melanocytic nevi. However, determining a lesion’s biological behavior primarily on CGH is limited by a relatively small series of corroborative cases without long term follow up. We present case of a pigmented lesion on the right cheek of a 4 year old boy. The lesion had features of a deep penetrating nevus, but the presence of frequent mitoses, tumor infiltrating lymphocytes, and microscopic foci of tumor necrosis were concerning for an unusual melanoma. We termed this lesion a melanocytic tumor of uncertain potential (MELTUMP) for these reasons. High-resolution array-CGH performed elsewhere on the lesion demonstrated no melanoma-associated genomic abnormalities. A sentinel lymph node biopsy of this patient later revealed multiple small tumor deposits. Although the presence of nodal involvement in similar lesions often do not lead to progressive and fatal disease, this case illustrates that atypical melanocytic lesions with nodal involvement may not demonstrate genomic abnormalities by CGH, and that histopathologic assessment remains paramount in defining these difficult melanocytic lesions. Further comprehensive study of these lesions is needed.

Recent gene expression microarray analyses have indicated that claudin-6 is specifically expressed in atypical teratoid rhabdoid tumors (AT/RTs), suggesting a role as a positive diagnostic marker in addition to SMARCB1 (INI1) loss, which is encountered in the majority of AT/RTs. In order to investigate the potential of claudin-6 as a diagnostic marker, expression was investigated in 59 AT/RTs and 60 other primary central nervous system (CNS) tumors, including primitive neuroectodermal tumors, medulloblastomas, choroid plexus tumors, and both pediatric and adult low- and high-grade gliomas using immunohistochemistry. Claudin-6 was expressed in 17/59 AT/RTs (29%), but also in a variety of other primary CNS tumors, including 60% of medulloblastomas and 21% of malignant gliomas. Even though high staining scores (2+ or 3+) were more often encountered in AT/RTs (Chi-square 4.177; P = 0.041), the overall frequency of claudin-6 staining was not significantly higher in AT/RTs as compared with the other tumors (17/59 vs. 16/60; Chi-square = 0.328; P = 0.567). In a subgroup of 43 AT/RT patients, of which follow-up data were available, claudin-6 expression did not show any correlation with survival. In conclusion, claudin-6 immunohistochemistry is of limited sensitivity and specificity for the diagnosis of AT/RT and does not correlate with clinical behavior.

Background: Through negative regulation of gene expression, microRNAs (miRNAs) can function in cancers as oncosuppressors, and they can show altered expression in various tumor types. Here we have investigated medulloblastoma tumors (MBs), which arise from an early impairment of developmental processes in the cerebellum, where Notch signaling is involved in many cell-fate-determining stages. MBs occur bimodally, with the peak incidence seen between 3-4 years and 8-9 years of age, although it can also occur in adults. Notch regulates a subset of the MB cells that have stem-cell-like properties and can promote tumor growth. On the basis of this evidence, we hypothesized that miRNAs targeting the Notch pathway can regulated these phenomena, and can be used in anti-cancer therapies. Methodology/Principal Findings: In a screening of MB cell lines, the miRNA miR-199b-5p was seen to be a regulator of the Notch pathway through its targeting of the transcription factor HES1. Down-regulation of HES1 expression by miR-199b-5p negatively regulates the proliferation rate and anchorage-independent growth of MB cells. MiR-199b-5p over-expression blocks expression of several cancer stem-cell genes, impairs the engrafting potential of MB cells in the cerebellum of athymic/nude mice, and of particular interest, decreases the MB stem-cell-like (CD133+) subpopulation of cells. In our analysis of 61 patients with MB, the expression of miR-199b-5p in the non-metastatic cases was significantly higher than in the metastatic cases (P = 0.001). Correlation with survival for these patients with high levels of miR-199b expression showed a positive trend to better overall survival than for the low-expressing patients. These data showing the down-regulation of miR-199b-5p in metastatic MBs suggest a potential silencing mechanism through epigenetic or genetic alterations. Upon induction of de-methylation using 5-aza-deoxycytidine, lower miR-199b-5p expression was seen in a panel of MB cell lines, supported an epigenetic mechanism of regulation. Furthermore, two cell lines (Med8a and UW228) showed significant upregulation of miR-199b-5p upon treatment. Infection with MB cells in an induced xenograft model in the mouse cerebellum and the use of an adenovirus carrying miR-199b-5p indicate a clinical benefit through this negative influence of miR-199b-5p on tumor growth and on the subset of MB stem-cell-like cells, providing further proof of concept. Conclusions/Significance: Despite advances in our understanding of the pathogenesis of MB, one-third of these patients remain incurable and current treatments can significantly damage long-term survivors. Here we show that miR-199b-5p expression correlates with metastasis spread, identifying a new molecular marker for a poor-risk class in patients with MB. We further show that in a xenograft model, MB tumor burden can be reduced, indicating the use of miR199b-5p as an adjuvant therapy after surgery, in combination with radiation and chemotherapy, for the improvement of anti-cancer MB therapies and patient quality of life. To date, this is the first report that expression of a miRNA can deplete the tumor stem cells, indicating an interesting therapeutic approach for the targeting of these cells in brain tumors. © 2009 Garzia et al.

In this article, we describe the morphologic and immunophenotypic features of 75 cases of pediatric anaplastic large cell lymphoma (ALCL). According to the World Health Organization classification, 49 cases were common subtype ALCL, and respectively, 3, 6, and 17 cases were small cell, lymphohistiocytic, or mixed histologic variants. Anaplastic lymphoma kinase positivity was detected in 90.7% of the tumors and, using a panel of 9 T-cell surface markers, 88% could be assigned to the T-cell lineage. A molecular analysis for the T-cell receptor γ (TCR- γ) and the heavy chain of the immunoglobulin H rearrangements was performed on 6/9 ALCLs with a null immunophenotype, and a TCR clonal pattern was detected in 5/6 cases. In addition, 94.1% were immunoreactive for 1 or more cytotoxic proteins (Tia1, granzyme B, or perforin), and 15% expressed CD56. Clusterin, CD83, and Pax5, respectively, expressed in 91.3%, 1.7%, and 0% of the ALCLs, were useful biomarkers for the differential diagnosis with Hodgkin's lymphomas.

AimGATA proteins are a family of zinc finger transcription factors regulating gene expression, differentiation and proliferation in various tissues. The expression of GATA-4 and FOG-2, one of its modulators, was studied in pediatric Sex Cord-Stromal tumors of the ovary, in order to evaluate their potential role as diagnostic markers and prognostic factors.Materials and methodsClinical and histological data of 15 patients, enrolled into the TREP Project since 2000 were evaluated. When available, immunostaines for FOG-2, GATA-4, α-Inhibin, Vimentin and Pancytokeratin were also analyzed.ResultsIn our series there were 6 Juvenile Granulosa Cell Tumors (JGCT), 6 Sertoli-Leydig Cell Tumors (SLCT), 1 Cellular Fibroma, 1 Theca Cell Tumor and 1 Stromal Sclerosing Tumor (SST). Thirteen patients obtained a complete remission (CR), 1 reached a second CR after the removal of a metachronous tumor and 1 died of disease. Inhibin was detectable in 11/15, Vimentin in 13/15, Pancytokeratin in 6/15, GATA-4 in 5/13 and FOG-2 in 11/15. FOG-2 was highly expressed in 5/6 JGCT, while GATA-4 was weakly detectable only in 1 of the cases. SLCT expressed diffusely FOG-2 (4/6) and GATA-4 (3/5). GATA-4 and FOG-2 were detected in fibroma and thecoma but not in the SST.ConclusionsPediatric granulosa tumors appear to express a FOG-2/GATA-4 phenotype in keeping with primordial ovarian follicles. High expression of GATA-4 does not correlate with aggressive behaviour as seen in adults, but it is probably involved in cell proliferation its absence can be associated with the better outcome of JGCT. SLCTs replicate the phenotype of Sertoli cells during embryogenesis in normal testis. In this group, the lack of expression of FOG-2 in tumors in advanced stages might reveal a hypothetical role in inhibiting GATA-4 cell proliferation pathway. In fibroma/thecoma group GATA-4 and FOG-2 point out the abnormal activation of GATA pathway and might be involved in the onset of these tumors.

Background Enhancer of Zeste Drosophila Homologue 2 (EZH2) is a key regulator of transcription as a member of polycomb repressive complex 2 (PRC2) which exerts repression of downstream genes and is correlated to invasiveness and progression of different tumours. Therefore, we evaluated the expression of PRC2 proteins in pediatric soft tissue sarcoma (rhabdomyosarcoma, RMS and extraosseous Ewing sarcoma, EES) correlating them to the clinical outcome of the patients. Methods We analyzed PRC2 protein expression by quantitative real time PCR, western blotting and immunohistochemistry in 17 soft tissue sarcomas (11 RMS and 6 EES) enrolled at Paediatric Oncology Units of the Second University of Naples. Expression analysis was performed for EZH2, SUZ12 and EED. Results Enhancer of Zeste Drosophila Homologue 2 was expressed with a different degree in 60 % of samples. Interestingly, the magnitude of EZH2 up regulation was significantly higher in patients presenting lymph node and/or distant metastases at the diagnosis. Moreover, patients overexpressing EZH2 had a lower probability of survival compared to patients negative or with low EZH2 expression. Conclusions Our study suggests that high EZH2 expression is associated to increased aggressiveness of the disease. Therefore, drugs that control its activity could be potentially used in the epigenetic target treatment of tumors with these alterations.