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Mitchell P. Wilson, Edward S. Johnson, Cynthia Hawkins, Kerry Atkins, Wael Alshaya and Jeffrey A. Pugh

Acute hemorrhagic presentation in pilocytic astrocytomas (PAs) has become increasingly recognized. This type of presentation poses a clinically emergent situation in those hemorrhages arising in PAs of the cerebellum, the most frequent site, because of the limited capacity of the posterior fossa to compensate for mass effect, predisposing to rapid neurological deterioration. As examples, we describe two cases of fatal hemorrhagic cerebellar PAs: one of a child with a slowly growing stereotypical WHO Grade I PA with a 1-year period of symptomatology that preceded a rapid clinical deterioration, and another of an asymptomatic child having a PA variant, presenting with progressive obtundation following a presumed Valsalva event. These two scenarios parallel previous reports in the literature of either a setting of progressive expression of cerebellar dysfunction and transient episodes of raised intracranial pressure (ICP), or abrupt onset of features of increased ICP in a previously well child. The literature is further reviewed for a current understanding of the factors that predispose, initiate and propagate bleeding, with specific reference to the role of vascular endothelial growth factor and other angiogenic agents in the genesis and stability of the vasculature in PAs. In this context, we propose that obliterative vascular mural hyalinization with associated altered flow dynamics and microaneurysm formation was the pathogenesis of the hemorrhage in our first case. In the second case, large tumor size, increased growth rate, looseness of the background myxoid matrix, and thinness of the tumor blood vessels with calcospherite deposition predisposed to vascular leakage and bleeding concurrent with sudden increases in intravascular hydrostatic pressure. In that cerebellar PAs are common, this report underscores the importance of considering in the differential diagnosis the possibility of a spontaneous hemorrhage in a posterior fossa PA in a child presenting with a sudden neurological ictus and raised ICP.

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John S. Kuo, Cynthia Hawkins, James T. Rutka and Martin H. Weiss

Object

The authors investigated the feasibility of using fat allografts (chemically treated to reduce the host immune response) for neurosurgical applications.

Methods

Subcutaneous fat specimens collected from New Zealand White rabbits were treated with DNAse I and sodium deoxycholate to reduce immunogenicity before subcutaneous, midscapular implantation in immunocompetent recipient rabbits. Allograft incorporation and the host-allograft response were examined at 1, 6, and 11 weeks by histopathological analysis. Control specimens of autograft and untreated fat allograft implants were examined for comparison.

Results

The host immune response was markedly reduced in the region around the chemically treated fat allografts when compared with untreated allografts, and was similar to the tolerant host response to autografts.

Conclusions

Based on their results, the authors suggest that fat allografts processed for reduced immunogenicity may be a convenient, viable alternative for neurosurgical applications.

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Mei Hua Li, Eric Bouffet, Cynthia E. Hawkins, Jeremy A. Squire and Annie Huang

The supratentorial primitive neuroectodermal tumors (PNETs) are a group of highly malignant lesions primarily affecting young children. Although these tumors are histologically indistinguishable from infratentorial medulloblastoma, they often respond poorly to medulloblastoma-specific therapy. Indeed, existing molecular genetic studies indicate that supratentorial PNETs have transcriptional and cytogenetic profiles that are different from those of medullo-blastomas, thus pointing to unique biological derivation for the supratentorial PNET. Due to the rarity of these tumors and disagreement about their histopathological diagnoses, very little is known about the molecular characteristics of the supratentorial PNET. Clearly, future concerted efforts to characterize the molecular features of these rare tumors will be necessary for development of more effective supratentorial PNET treatment protocols and appropriate disease models. In this article the authors review existing molecular genetic data derived from human and mouse studies, with the aim of providing some insight into the putative histogenesis of these rare tumors and the underlying transforming pathways that drive their development. Studies of the related but distinct pineoblastoma PNET are also reviewed.

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Ute Bartels, Cynthia Hawkins, Jing Ma, Michael Ho, Peter Dirks, James Rutka, Derek Stephens and Eric Bouffet

Object

The authors’ aim in conducting this study was to investigate retrospectively the prognostic significance of angiogenic features in optic pathway/hypothalamic gliomas (OPHGs) in children.

Methods

Patients were identified in whom a diagnosis of OPHG was made using pathological analysis at the Toronto Hospital for Sick Children between 1985 and 2002. Tumor specimens were reviewed for diagnostic accuracy and adequacy of the specimen. Sections were immunostained with factor VIII to assess microvessel density (MVD). A ratio of α–smooth muscle actin to factor VIII immunostaining was calculated to arrive at a vascular maturity index (VMI). Vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) immunostaining were performed to evaluate angiogenic factors. In addition, the MIB-1 labeling index (LI) was used to assess proliferation. These factors were evaluated with respect to progression-free survival (PFS).

Forty-one of 60 patients originally identified had adequate samples and follow up for inclusion in the study. Of these, eight patients had coexisting neurofibromatosis Type 1. Twenty-eight patients experienced tumor progression after the initial treatment (surgery with or without adjuvant treatment). Thirty-eight patients are still alive. A high MVD (> 21 vessels/1.2 mm2) was associated with a significantly higher rate of progression compared with a low MVD (< 21 vessels/1.2 mm2; p = 0.017). Microvessel density was also predictive of reduced PFS on multivariate analysis stratified for extent of resection (p = 0.04), and VMI as well as intensity and distribution of VEGF and VEGFR staining and the MIB-1 LI were not significantly associated with PFS.

Conclusions

These findings suggest that MVD is the best current predictor of PFS in incompletely resected OPHGs. This information highlights the importance of angiogenesis in regard to low-grade gliomas.

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Katrin Scheinemann, Ute Bartels, Annie Huang, Cynthia Hawkins, Abhaya V. Kulkarni, Eric Bouffet and Uri Tabori

Object

Intramedullary spinal cord low-grade gliomas (LGGs) are rare CNS neoplasms in pediatric patients, and there is little information on therapy for and outcome of these tumors in this population. Furthermore, most patient series combine adult and pediatric patients or high- and low-grade tumors, resulting in controversial data regarding optimal treatment of these children. To clarify these issues, the authors performed a regional population-based study of spinal cord LGGs in pediatric patients.

Methods

All pediatric patients with LGGs treated during the MR imaging era (1985–2007) were identified in the comprehensive database of the Hospital for Sick Children in Toronto. Data on demographics, pathology, treatment details, and outcomes were collected.

Results

Spinal cord LGGs in pediatric patients constituted 29 (4.6%) of 635 LGGs. Epidemiological and clinical data in this cohort were different than in patients with other spinal tumors and strikingly similar to data from pediatric patients with intracranial LGGs. The authors observed an age peak at 2 years and a male predominance in patients with these tumors. Histological testing revealed a Grade I astrocytoma in 86% of tumors. Although 5-year progression-free survival for the entire group was 48 ± 9%, all patients were alive at a median follow-up of 8.2 years. Five-year progression-free survival was 88 ± 13% for patients undergoing gross-total resection and 34 ± 11% for those undergoing all other therapies, respectively (p = 0.02). Chemotherapy and radiation therapy showed similar efficacy, achieving sustained tumor control in most patients. However, this excellent survival rate was associated with an 83% rate of significant neurological and orthopedic sequelae.

Conclusions

This study provides basic data on the incidence, clinical course, and outcome of spinal cord LGGs in pediatric patients. The similarities between spinal and intracranial LGGs in pediatric patients showing excellent survival but high morbidity suggest that a less aggressive approach may be the preferable treatment option for these patients.

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Niketa C. Shah, Amit Ray, Ute Bartels, James Rutka, Eric Bouffet, James Drake, Cynthia E. Hawkins and Annie Huang

✓ The authors report on 2 newborn infants with the unusual presentation of intrinsic brainstem tumors. Both nondysmorphic, full-term neonates had cranial nerve palsies and hypotonia. Diagnoses of diffuse intrinsic brainstem gliomas were made on the basis of magnetic resonance imaging, which showed large expansive, nonenhancing intrinsic pontine masses. Intrinsic pontine tumors, characteristically seen in school-age children, are most often high-grade gliomas that are almost invariably fatal. However, the microanatomy and natural history of pontine tumors in neonates are unknown. With parental consent, both newborns were treated expectantly with supportive care but died of progressive disease by 2 weeks of age. In one child, postmortem examination revealed a primary brainstem primitive neuroectodermal tumor. The authors conclude that, as in older children, neonatal intrinsic brainstem tumors may be of a highly malignant nature. The rapid tumor progression in both cases indicates that where a diagnostic procedure may pose significant risks, supportive observation can aid in distinguishing malignant from benign tumor growth.

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Chinatsu Kasuga, Yukiko Nakahara, Shigeo Ueda, Cynthia Hawkins, Michael D. Taylor, Christian A. Smith and James T. Rutka

Object

Cancer testis antigens (CTAs) were initially identified by their ability to elicit autologous T-cell–mediated immune responses in patients with melanoma. The CTA genes are widely expressed in a variety of human cancers, such as melanoma, breast cancer, lung cancer, esophageal cancer, and hepatocellular carcinoma; however, their expression in pediatric brain tumors, such as medulloblastoma (MB), has not been the subject of in-depth analysis. The MAGE proteins are members of the CTA family and have been shown to correlate with tumor development, aggressive clinical course, or resistance to chemotherapeutic agents. The authors undertook this study to examine the expression and role of MAGE proteins in human MB cell lines and specimens.

Methods

From a transcriptional profiling study in which 47,000 genes in MB cell lines were examined, the authors identified members of the MAGE and GAGE families as being highly expressed. A series of MB tumors was examined using both immunohistochemistry and Western blot analysis with antibodies to the MAGE-A family, MAGE-A1, and GAGE proteins.

Results

Western blot analysis showed expression of these 3 proteins (MAGE-A family, MAGE-A1, and GAGE) in 62, 46, and 84%, respectively, of MB specimens examined. In addition, a correlation was observed between the expression of MAGE and GAGE genes and resistance of MB cells to chemotherapeutic agents. The functional significance of this correlation was examined in MAGE knockdown studies, and increased drug-induced cytotoxicity was observed in UW426 MB cells following treatment with chemotherapeutic drugs. Cleaved caspase-3 was found in UW426/MAGE small interfering (si)RNA–inhibited cells treated with cisplatin, but not in UW426 cells treated with cisplatin alone at the same concentration.

Conclusions

These data show that MAGE and GAGE family members are expressed in MB cell lines and specimens, and that inhibition of MAGE and GAGE genes by siRNA increases apoptosis of MB cells and sensitizes them to certain chemotherapeutic agents such as cisplatin and etoposide.

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Michael J. Ellis, Samuel Cheshier, Sunjay Sharma, Derek Armstrong, Cynthia Hawkins, Eric Bouffet, James T. Rutka and Michael D. Taylor

Among the neoplastic conditions that affect patients with neurofibromatosis Type 1 (NF1) are malignant peripheral nerve sheath tumors (MPNSTs), which typically arise from peripheral nerves of the limbs, trunk, and lumbar and brachial plexuses. Ionizing radiation is an established risk factor for MPNST development, especially in susceptible patients such as those with NF1. Patients with NF1 are also at risk for intracranial aneurysms, which are increasingly being successfully managed with endovascular therapies. The authors describe the case of a 9-year-old, previously healthy girl who presented in extremis with a right frontal intracerebral hemorrhage resulting from a ruptured right middle cerebral artery (MCA) trifurcation aneurysm. Following urgent decompressive craniectomy, the patient underwent endovascular coil embolization of the MCA aneurysm without complication. Given her mother's history of NF1, the child underwent genetic testing, which disclosed signs positive for NF1. The patient recovered well, but follow-up MR imaging and MR angiography performed at 14 months demonstrated a large frontotemporal mass encasing the right MCA trifurcation. The patient underwent frontotemporal craniotomy and subtotal resection of the mass, which was histologically found to be an intracranial MPNST. The patient received chemotherapy and focal radiation therapy and remains alive at 6 months postresection. To the authors' knowledge, this represents the only known case of intracranial neoplasm arising in the region of an intracranial aneurysm repaired by endovascular coil embolization. While patients with NF1 represent a population with genetic susceptibility to radiation-induced tumors, the pathogenesis of intracerebral MPNSTs remains poorly understood.

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Lucie Lafay-Cousin, Gillian Lindzon, Michael D. Taylor, Walter Hader, Cynthia Hawkins, Robert Nordal, Normand Laperriere, Suzanne Laughlin, Eric Bouffet and Ute Bartels

OBJECT

Primary CNS sarcomas are very rare pediatric tumors with no defined standard of care.

METHODS

This study was a retrospective review of children diagnosed with a primary CNS sarcoma and treated at 2 Canadian tertiary care centers between 1995 and 2012. This report focuses on patients with cerebral hemispheric tumor location due to their specific clinical presentation.

RESULTS

Fourteen patients with nonmetastatic primary CNS sarcoma were identified; in 9 patients, tumors were located in the cerebral hemisphere and 7 of these patients presented with intratumoral hemorrhage. One infant who died of progressive disease postoperatively before receiving any adjuvant therapy was not included in this study. The final cohort therefore included 8 patients (4 males). Median patient age at diagnosis was 11.8 years (range 5.8–17 years). All tumors were located in the right hemisphere. Duration of symptoms prior to diagnosis was very short with a median of 2 days (range 3–7 days), except for 1 patient. Three (37.5%) patients had an underlying diagnosis of neurofibromatosis Type 1 (NF1). Gross-total resection was achieved in 5 patients. The dose of focal radiation therapy (RT) ranged between 54 Gy and 60 Gy. Concomitant etoposide was administered during RT. ICE (ifosfamide, carboplatin, etoposide) chemotherapy was administered prior to and after RT for a total of 6–8 cycles. Seven of the 8 patients were alive at a median time of 4.9 years (range 1.9–17.9 years) after treatment.

CONCLUSIONS

In this retrospective series, patients with primary CNS sarcomas located in the cerebral hemisphere most commonly presented with symptomatic acute intratumoral hemorrhage. Patients with NF1 were overrepresented. The combination of adjuvant ICE chemotherapy and focal RT provided encouraging outcomes.

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Christian Schneider, Vijay Ramaswamy, Abhaya V. Kulkarni, James T. Rutka, Marc Remke, Uri Tabori, Cynthia Hawkins, Eric Bouffet and Michael D. Taylor

OBJECT

While medulloblastoma was initially thought to comprise a single homogeneous entity, it is now accepted that it in fact comprises 4 discrete subgroups, each with its own distinct demographics, clinical presentation, transcriptomics, genetics, and outcome. Hydrocephalus is a common complication of medulloblastoma and not infrequently requires CSF diversion. The authors report the incidence of CSF diversion surgery in each of the subgroups of medulloblastoma (Wnt, Shh, Group 3, and Group 4).

METHODS

The medical and imaging records for patients who underwent surgery for medulloblastoma at The Hospital for Sick Children were retrospectively reviewed. The primary outcome was the requirement for CSF diversion surgery either before or within 60 days of tumor resection. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) was compared among subgroups.

RESULTS

Of 143 medulloblastoma patients, treated from 1991 to 2013, sufficient data were available for 130 patients (15 with Wnt, 30 with Shh, 30 with Group 3, and 55 with Group 4 medulloblastomas). Of these, 28 patients (22%) ultimately underwent CSF diversion surgery: 0% with Wnt, 29% with Shh, 29% with Group 3, and 43% with Group 4 tumors. Patients in the Wnt subgroup had a lower incidence of CSF diversion than all other patients combined (p = 0.04). Wnt patients had a lower mCPPRH score (lower risk of CSF diversion, p = 0.045), were older, had smaller ventricles at diagnosis, and had no leptomeningeal metastases.

CONCLUSIONS

The overall rate of CSF diversion surgery for Shh, Group 3, and Group 4 medulloblastomas is around 30%, but no patients in the present series with a Wnt medulloblastoma required shunting. The low incidence of hydrocephalus in patients with Wnt medulloblastoma likely reflects both host factors (age) and disease factors (lack of metastases). The absence of hydrocephalus in patients with Wnt medulloblastomas likely contributes to their excellent rate of survival and may also contribute to a higher quality of life than for patients in other subgroups.