Poorly Differentiated Chordoma of the Clivus With Loss of SMARCB1 Expression in a Pediatric Patient: A Case Report.

Poorly differentiated chordoma (PDC) is a rare, aggressive subtype of chordoma. A two-year-old girl presented with cervical pain, limb paralysis and respiratory failure. Magnetic resonance imaging and positron emission tomography-computed tomography revealed a tumor compressing the pons at the clivus and osteoblastic metastatic lesions of the left upper arm and right iliac bone. Her tumors shrank substantially after treatment with chemotherapy and proton beam therapy. Our initial diagnosis was an atypical teratoma/rhabdoid tumor, but final diagnosis of PDC was made on the basis of the immunohistochemical expression of brachyury. In addition, the detection of SMARCB1/INI1 mutation confirmed the diagnosis of PDC.

Primary histiocytic sarcoma of the clivus with focal extension into central nervous system and neurologic manifestations: First description at an unusual site with an overwhelming and rapid progression.

Histiocytic sarcoma (HS) is a rare malignant neoplasm of macrophage-dendritic cell lineage that can occur at any site. Primary base of skull involvement is exceedingly rare. We present the case of a previously healthy 56-year-old man who complained of headaches and showed localized neurologic symptoms. Magnetic resonance imaging demonstrated a hyperintense and enhancing mass involving the sphenoid bone and the clivus with an extradural component that compressed the distal pons. The differential diagnosis included chordoma or chondrosarcoma. An endoscopic trans-sphenoidal resection was performed. Microscopically, the tumor showed epithelioid and spindle morphology with atypia, mitoses, and necrosis. No osteoid, cartilaginous, or myxoid matrix was identified. By immunohistochemistry, the tumor was positive for CD68 (KP-1) and lysozyme, variably positive for CD4, CD11c, CD14, CD68 (PGM-1), CD45, and CD163, and negative for markers of epithelial, melanocytic, lymphoid, myeloid, muscle, and dendritic cell origin. Expression of PD-L1 by immunohistochemistry and BRAF V600E mutation analysis by PCR were negative. Tumor recurrence developed after radiation treatment with overwhelming progression into a largely infiltrating mass within 2 weeks with clinical deterioration, and the patient died 3 months later. To our knowledge, this represents the first case of primary HS of the clivus reported to date in the English literature, further expanding the spectrum of neoplasms seen at this site as well as the sites where HS can be seen. The overall prognosis of HS in the skull base is poor, with no standard treatment. Further research is warranted to develop effective treatment approaches, which in the future may rely on the expression of checkpoint inhibitors and/or specific molecular markers.

Chordoma of the Clivus and Acute Myeloid Leukemia: Is There a Connection?

Chordoma is a rare cancer in children and understanding the genesis of this tumor may contribute to treatment approaches. Evidence has proposed VDC/IE (vincristine, doxorubicin, cyclophosphamide/ifosfamide, etoposide) as a treatment option for young patients with chordoma to avoid the long-term effects of radiation therapy. We present a case of acute myeloid leukemia developing during treatment of localized chordoma of the clivus in a 20-month-old male. We propose a genomic relationship that may have contributed to the development of clival chordoma and acute myeloid leukemia without a latency period and advocate for genomic sequencing in children with chordoma before the initiation of systemic therapies.

The identification of H3F3A mutation in giant cell tumour of the clivus and the histological diagnostic algorithm of other clival lesions permit the differential diagnosis in this location.

BACKGROUND: Giant Cell Tumour of Bone (GCT) is a locally aggressive primary bone tumour that usually occurs at the epiphyses of the long bones of the appendicular skeleton with a tendency to recurrence. Recurrent somatic H3F3A mutations have been described in 92% of GCT cases. GCTs involving the Clivus are extremely rare lesions and less than 15 cases are described in the literature. They represent a surgery challenge and are easily misdiagnosed. Our aim was to reveal if the genetic bases underlying Clival GCTs were the same of GCTs of long bones to improve the diagnosis and treatment. METHODS: The targeted somatic sequencing of GCT-related genes (H3F3A, H3F3B, IDH1, IDH2 and ZNF687) was performed on Clival GCT biopsies of two different cases. Histological analyses on the same tissues were used to detect the neoplastic population and its expression profile. RESULTS: Sanger sequencing revealed that both patients were positive for the p.Gly34Trp mutation in the H3F3A gene. Immunofluorescence assay using monoclonal antibody, specifically detecting the mutant H3.3, highlighted that the mutation only involved the mononuclear cell population and not the multinucleated giant cells. Moreover, immunohistochemistry assay showed that RANKL was highly expressed by the stromal cells within Clival GCT, mimicking what happens in GCT of the long bones. In addition, systematic literature review allowed us to generate a histology-based diagnostic algorithm of the most common clival lesions. CONCLUSIONS: We conclude that the Clival GCT is genetically defined by somatic mutation in the H3F3A gene, linking it to the GCT of long bones. The similarity with GCTs of long bones let us to hypothesize the utility of Denosumab therapy (already effective for GCTs) in these surgically challenging cases. Moreover, H3F3A genetic screening can be combined to the histological analysis to differentiate GCTs from morphologically similar giant cell-rich sarcomas, while the histological diagnostic algorithm could help the differential diagnosis of other clival lesions.

Analysis of clinical factors and PDGFR-ß in predicting prognosis of patients with clival chordoma.

OBJECTIVEIn this study, the authors' aim was to research clinical features and prognostic factors in patients harboring clival chordomas and explore the relationship between platelet-derived growth factor receptor-ß (PDGFR-ß) expression and tumor invasion and prognosis of clival chordoma.METHODSA total of 242 patients were retrospectively analyzed. Clinical information, including extent of resection, Al-Mefty classification, postoperative complications, and postoperative radiotherapy, was reviewed. Kaplan-Meier analysis was used to estimate survival time. Immunohistochemical analysis, quantitative reverse transcription polymerase chain reaction, and Western blotting were used to measure the expression level of proteins or mRNA. Transwell assaying was performed to measure the invasive ability of the tumor cells.RESULTSAccording to the Al-Mefty classification, there were 37, 112, and 93 type I, II, and III tumors, respectively. Gross-total resection (GTR) was achieved in 86 cases (35.5%), subtotal resection (STR) in 63 cases (26.0%), and partial resection (PR) in 93 cases (38.4%). The 5-year progression-free survival (PFS) and overall survival (OS) rates in the GTR group were significantly higher than those in the non-total resection (NTR; i.e., STR and PR) group (p < 0.001). The 5-year PFS and OS rates for patients with type I tumors were significantly higher than those for patients harboring types II and III tumors (p < 0.001). In the NTR group, the median PFS and OS of patients with lower PDGFR-ß expression were significantly longer than those of patients with higher PDGFR-ß expression. Reduction of PDGFR-ß suppressed the invasion ability of cells in vitro. In addition, reduction of PDGFR-ß can obviously downregulate the expression levels of mammalian target of rapamycin (mTOR) or phospho-mTOR.CONCLUSIONSExtent of resection, Al-Mefty classification, primary tumor, postoperative radiotherapy, and PDGFR-ß expression level are valuable prognostic factors in patients with clival chordomas. PDGFR-ß could regulate invasion through the mTOR pathway in clival chordoma cells.

Study of angiogenic signaling pathways in hemangioblastoma.

Hemangioblastoma (HB) is mainly located in the brain and the spinal cord. The tumor is composed of two major components, namely neoplastic stromal cells and abundant microvessels. Thus, hyper-vascularization is the hallmark of this tumor. Despite the identification of germline and/or epigenetic mutations of Von Hippel Lindau (VHL) gene as an important pathogenic mechanism of HB, little is known about the molecular signaling involved in this highly vascularized tumor. The present study investigated the key players of multiple angiogenic signaling pathways including VEGF/VEGFR2, EphB4/EphrinB2, SDF1α/CXCR4 and Notch/Dll4 pathways in surgical specimens of 22 HB. The expression of key angiogenic factors was detected by RT2 -PCR and Western blot. Immunofluorescent staining revealed the cellular localization of these proteins. We demonstrated a massive upregulation of mRNA levels of VEGF and VEGFR2, CXCR4 and SDF1α, EphB4 and EphrinB2, as well as the main components of Dll4-Notch signaling in HB. An increase in the protein expression of VEGF, CXCR4 and the core-components of Dll4-Notch signaling was associated with an activation of Akt and Erk1/2 and accompanied by an elevated expression of PCNA. Immuofluorescent staining revealed the expression of VEGF and CXCR4 in endothelial cells as well as in tumor cells. Dll4 protein was predominantly found in tumor cells, whereas EphB4 immunoreactivity was exclusively detected in endothelial cells. We conclude that multiple key angiogenic pathways were activated in HB, which may synergistically contribute to the abundant vascularization in this tumor. Identification of these aberrant pathways provides potential targets for a possible future application of anti-angiogenic therapy for this tumor, particularly when a total surgical resection becomes difficult due to the localization or multiplicity of the tumor.

MGMT promoter methylation status in clival chordoma.

Chordomas are rare, slow-growing neoplasms, characterized by locally aggressive growth patterns and high local recurrence rates. To the best of our knowledge, the MGMT promoter methylation status has not been studied in a population of patients with chordomas to determine if a biologic rationale exists to support the use of temozolomide. We here show for the first time that methylation of MGMT promoter is present in a significant portion or recurring clival chordomas; on the contrary in clival chordomas without recurrence MGMT promoter was always unmethylated (p = 0.0317). Although these observations need to be confirmed in a larger study population, our results (1) indicate that methylation of MGMT promoter is present in a significant portion of recurring chordomas, and (2) prompt further investigation into the potential role of temozolomide as an adjuvant treatment of these tumors.

Role of MYC in Medulloblastoma.

Since its discovery as an oncogene carried by the avian acute leukemia virus MC29 in myelocytomatosis (Roussel et al. 1979) and its cloning (Vennstrom et al. 1982), c-MYC (MYC), as well as its paralogs MYCN and MYCL1, has been shown to play essential roles in cycling progenitor cells born from proliferating zones during embryonic development, and in all proliferating cells after birth. MYC deletion induces cell-cycle exit or cell death, depending on the cell type and milieu, whereas MYC and MYCN amplification or overexpression promotes cell proliferation and occurs in many cancers. Here, we review the relationship of MYC family proteins to the four molecularly distinct medulloblastoma subgroups, discuss the possible roles MYC plays in each of these subgroups and in the developing cells of the posterior fossa, and speculate on possible therapeutic strategies targeting MYC.

Chiari malformation type I: a case-control association study of 58 developmental genes.

Chiari malformation type I (CMI) is a disorder characterized by hindbrain overcrowding into an underdeveloped posterior cranial fossa (PCF), often causing progressive neurological symptoms. The etiology of CMI remains unclear and is most likely multifactorial. A putative genetic contribution to CMI is suggested by familial aggregation and twin studies. Experimental models and human morphometric studies have suggested an underlying paraxial mesoderm insufficiency. We performed a case-control association study of 303 tag single nucleotide polymorphisms (SNP) across 58 candidate genes involved in early paraxial mesoderm development in a sample of 415 CMI patients and 524 sex-matched controls. A subgroup of patients diagnosed with classical, small-PCF CMI by means of MRI-based PCF morphometry (n = 186), underwent additional analysis. The genes selected are involved in signalling gradients occurring during segmental patterning of the occipital somites (FGF8, Wnt, and retinoic acid pathways and from bone morphogenetic proteins or BMP, Notch, Cdx and Hox pathways) or in placental angiogenesis, sclerotome development or CMI-associated syndromes. Single-marker analysis identified nominal associations with 18 SNPs in 14 genes (CDX1, FLT1, RARG, NKD2, MSGN1, RBPJ1, FGFR1, RDH10, NOG, RARA, LFNG, KDR, ALDH1A2, BMPR1A) considering the whole CMI sample. None of these overcame corrections for multiple comparisons, in contrast with four SNPs in CDX1, FLT1 and ALDH1A2 in the classical CMI group. Multiple marker analysis identified a risk haplotype for classical CMI in ALDH1A2 and CDX1. Furthermore, we analyzed the possible contributions of the most significantly associated SNPs to different PCF morphometric traits. These findings suggest that common variants in genes involved in somitogenesis and fetal vascular development may confer susceptibility to CMI.

The incidence, volume, absorption, and timing of supratentorial pneumocephalus during posterior fossa neurosurgery conducted in the sitting position.

BACKGROUND: Supratentorial pneumocephalus (STP) is a known complication of neurosurgical procedures of the posterior fossa when conducted in the sitting position. Few studies have examined STP as differentiated from pneumocephalus in the operative field. METHODS: Ninety-five of 106 consecutive patients had postoperative radiographic studies and median nerve somatosensory evoked potential (SSEP) recording during surgery. STP was identified on postoperative skull films or computerized tomography (CT). STP volume was measured on CT scans. SSEP changes were identified in the monitoring records. RESULTS: STP was identified in 40 patients (42.1%). STP volume on CT scans within 4 hours of surgery ranged from 6 to 280 cm3 (cubic centimeters). An extraventricular drain or ventriculo-peritoneal shunt did not increase the incidence of STP (P=0.85). The absorption of STP in 5 patients with multiple CT scans showed an immediate reduction of 24% followed by exponential decay with an half life of 1.5 days. Four patients with an extraventricular drain or ventriculo-peritoneal shunt had excessive volume of STP when measured at 1 day or later. Six patients with significant SSEP amplitude reductions attributed to STP had volumes exceeding 90 cm3 on a CT scan within 4 hours of surgery. The onset of these changes occurred at various times from dural opening to closing. CONCLUSIONS: STP is common after posterior fossa neurosurgical procedures conducted in the sitting position. Further studies are needed to fully characterize the absorption of air and the timing of the entry.

[Histobiological features of posterior cranial fossa meningiomas and their impact on follow-up].

Total removal of posterior cranial fossa meningiomas often leads to complications due to localization, direction and nature of tumor growth. Radical excision as well as histological grade are the principal factors determining recurrence of disease in follow-up period. The paper evaluates the role of ki67 in progression of posterior cranial fossa meningiomas. We performed 189 immunohistochemical studies and katamnestic analysis of patients operated in Burdenko Neurosurgical Institute (Moscow). We showed that level of expression of ki67 correlates with histological grade of posterior fossa meningiomas. We established that recurrence-free survival depends on ki67. This allows prediction of prognosis. Low expression of ki67 corresponds longer recurrence-free survival. If ki67 expression is over 4% recurrence within 2 years after surgery is observed significantly more frequently. Multifactor statistical analysis confirmed prognostic value of ki67 especially in females and patients below 50 because terms of recurrences in these populations are significantly smaller. Obtained data prove versatility of ki67 in neurooncology which should enable its wider application in neurosurgical clinics.

Preterm birth and disruptive cerebellar development: assessment of perinatal risk factors.

OBJECTIVE: Abnormal cerebellar development was recently recognized to be related to prematurity. Aim of the present study was to evaluate preterm birth and possible peri- and postnatal risk factors associated with this type of brain injury. PATIENTS AND METHODS: We report on a series of 35 very low birth weight infants (birth weight 986+/-257g S.D.) born between 24 and 32 weeks of gestation (27.0+/-1.8 weeks of gestation S.D.) sustaining disruption of cerebellar development after preterm birth. Perinatal medical records of study patients were compared to 41 preterm control infants (birth weight 900+/-358g S.D., gestational age 26.3+/-2.1 weeks S.D.) with normal cerebellar development on MRI scan. RESULTS: A severely compromised postnatal condition with consecutive intubation and catecholamine support was found to be significant risk factor. Additional supratentorial hemorrhagic brain injury followed by posthemorrhagic hydrocephalus, neurosurgical interventions and hemosiderin deposits on the cerebellar surface were significantly related to disruptive cerebellar development. No other differences in perinatal factors were found between the groups. CONCLUSION: Premature birth between 24 and 32 gestational weeks associated with poor postnatal conditions and complicated supratentorial hemorrhagic brain lesions represents a high-risk situation for disruption of cerebellar development.

[Study on clinical significance of fetal posterior fossa fluid].

OBJECTIVE: To discuss the clinical significance of accumulated fluid in fetal posterior fossa. METHODS: Prenatal ultrasonography examination was performed on 5 400 woman at more than 20 weeks gestation, 110 women with fetus accumulated fluid in the posterior fossa more than 5mm were included in this study. The changes of accumulated fluid in fetal posterior fossa and the associated intracranial and extracranial anomalies were observed regularly every 2 or 3 weeks until delivery. The infants were also followed up. RESULTS: The incidence of the fetal posterior fossa fluid was 2.0%. Generally, the accumulated fluid in fetal posterior fossa was diagnosed at first time at 22 approximately 41 gestation weeks, median was (31 +/- 4) weeks. Most of them were be found between 29 approximately 32 weeks (42 cases, 38.2%), and the maximum amount of accumulated fluid in fetal posterior fossa was also in 29 approximately 32 gestation weeks (39 cases, 35.5%). The amount of accumulated fluid was from 6 mm to 26 mm, mean (11 +/- 3) mm, mostly between 10 approximately 14 mm (79 cases, 71.8%). The incidence of defected infants was 4.0%, 7.6% and 83.3% respectively, when the posterior fossa fluid was less than 10 mm, 10 approximately 14 mm and more than 15 mm. CONCLUSION: Most of cases could be diagnosed between 29 approximately 32 weeks gestation. The more fluid in the posterior fossa found, the more defected fetal or infant would be observed. In cases of more than 10 mm, especially more than 15 mm, anomales should be observed carefully.