Pattern of recurrence in children with midline posterior fossa malignant neoplasms

Proteomic analysis of cerebrospinal fluid from children with central nervous system tumors identifies candidate proteins relating to tumor metastatic spread

Central nervous system (CNS) tumors are the most common solid tumors in childhood. Since the sensitivity of combined cerebrospinal fluid (CSF) cytology and radiological neuroimaging in detecting meningeal metastases remains relatively low, we sought to characterize the CSF proteome of patients with CSF tumors to identify biomarkers predictive of metastatic spread. CSF samples from 27 children with brain tumors and 13 controls (extra-CNS non-Hodgkin lymphoma) were processed using core-shell hydrogel nanoparticles, and analyzed with reverse-phase liquid chromatography/electrospray tandem mass spectrometry (LC-MS/MS). Candidate proteins were identified with Fisher's exact test and/or a univariate logistic regression model. Reverse phase protein array (RPPA), Western blot (WB), and ELISA were used in the training set and in an independent set of CFS samples (60 cases, 14 controls) to validate our discovery findings. Among the 558 non-redundant proteins identified by LC-MS/MS, 147 were missing from the CSF database at http://www.biosino.org. Fourteen of the 26 final top-candidate proteins were chosen for validation with WB, RPPA and ELISA methods. Six proteins (type 1 collagen, insulin-like growth factor binding protein 4, procollagen C-endopeptidase enhancer 1, glial cell-line derived neurotrophic factor receptor α2, inter-alpha-trypsin inhibitor heavy chain 4, neural proliferation and differentiation control protein-1) revealed the ability to discriminate metastatic cases from controls. Combining a unique dataset of CSFs from pediatric CNS tumors with a novel enabling nanotechnology led us to identify CSF proteins potentially related to metastatic status.

[Magnetic resonance imaging of infratentorial anaplastic ependymoma in children]

OBJECTIVE

To show the main findings for anaplastic ependymoma on MRI.

MATERIAL AND METHODS

We reviewed all patients diagnosed with anaplastic ependymoma at our tertiary hospital during a six-year period. We recorded the MRI findings for this type of tumor (on conventional sequences following the protocol for the study of CNS tumors, diffusion-weighted imaging, contrast-enhanced sequences, and MR spectroscopy).

RESULTS

Our series comprises seven children with infratentorial anaplastic ependymoma. We found no definitive characteristics to distinguish between grade II and grade III tumors before histology, as none of the lesions had spread to the cerebrospinal fluid at diagnosis or showed increased restriction in the diffusion-weighted sequence.

CONCLUSIONS

The MRI characteristics cannot definitively distinguish between grade II ependymomas and anaplastic grade III ependymomas. Only a few details about diffusion and dissemination to the cerebrospinal fluid, if present, can distinguish between these types at imaging.

Imaging of ependymomas: MRI and CT

The imaging features of intracranial and spinal ependymoma are reviewed with an emphasis on conventional magnetic resonance imaging (MRI), perfusion MRI and proton magnetic resonance spectroscopy, and computed tomography. Imaging manifestations of leptomeningeal dissemination of disease are described. Finally, salient imaging features obtained in the postoperative period to evaluate completeness of surgical resection, and thereafter for long-term surveillance for disease recurrence, are reviewed.

Role of spinal MRI in the follow-up of children treated for medulloblastoma

BACKGROUND

The purpose of the current study was to describe the usefulness of spinal magnetic resonance imaging (MRI) in children with medulloblastoma or primitive neuroectodermal tumor (PNET) of the posterior fossa.

METHODS

Children consecutively diagnosed with medulloblastoma/PNET and followed in the Hospital for Sick Children/Toronto were identified. A homogenous cohort of children treated with craniospinal irradiation as part of their initial treatment was considered. Contrast-enhanced spinal MRIs done concomitantly with cranial MRIs (doublets) were reviewed. Recurrence was defined as any new abnormal lesion (in the brain or in the spine) in symptomatic or asymptomatic patients. Doublets after the first recurrence were excluded in the final analysis. The utility of a spinal MRI in the presence of a negative cranial MRI was assessed.

RESULTS

In all, 73 patients (21 females and 52 males; median age, 6.6 years, median follow-up time, 4.3 years) had at least 1 evaluable doublet during the follow-up period. Since concomitant cranial and spinal MRI was introduced as the standard evaluation for medulloblastoma/PNET in 1991, 286 doublets were evaluable. Fourteen spinal MRIs and 25 cranial MRIs showed new nodular or leptomeningeal lesions. In 2 patients, repeat MRIs ruled out recurrence (false-positive). All confirmed spinal recurrences were associated with intracranial recurrence. Of 261 doublets with negative cranial MRI, no new lesion was identified on spinal MRI.

CONCLUSIONS

An absence of progression on cranial MRI is highly predictive of absence of progression on spinal MRI. There is little evidence that surveillance spinal MRI (in children who underwent craniospinal radiation as part of their initial treatment) improves the detection of recurrences in children with medulloblastoma.

From the archives of the AFIP: medulloblastoma: a comprehensive review with radiologic-pathologic correlation

Medulloblastoma is the most common pediatric central nervous system malignancy and the most common primary tumor of the posterior fossa in children. This highly malignant neoplasm occurs more frequently in males and usually before 10 years of age. Clinical symptoms and signs are generally brief, typically less than 3 months in duration, and reflect the strong predilection of this tumor to arise within the cerebellum, most often in the vermis. Although much less common, the disease may also occur in adults, usually in the 3rd and 4th decades of life. Surgical resection, radiation therapy, and chemotherapy have substantially lowered the mortality associated with this tumor, with 5-year survival rates now commonly well above 50%. Still, both dissemination at the time of diagnosis and recurrence remain obstacles in achieving a cure. The tumor has characteristic hyperattenuation on unenhanced computed tomographic scans that reflects the high nuclear-cytoplasmic ratio seen at histologic analysis. The tumor typically appears heterogeneous on images, findings that are related to cyst formation, hemorrhage, and calcification and that are even more pronounced with magnetic resonance (MR) imaging. Evidence of leptomeningeal metastatic spread is present in 33% of all cases at the time of diagnosis and is well evaluated with contrast-enhanced MR imaging of the brain and the spine. Although controversial, postoperative surveillance with MR imaging is performed at most institutions in the hope of facilitating a better outcome. With continued research, treatment of these common neoplasms should improve, perhaps even achieving a cure in the future.

Surveillance neuroimaging of intracranial medulloblastoma in children: how effective, how often, and for how long?

OBJECT

The goal of this paper was to review brain and spine images obtained in children with medulloblastomas to determine the risk factors for tumor recurrence and to assess the impact of surveillance imaging on patient outcomes among patients who remain alive 1 month postsurgery.

METHODS

Imaging studies and clinical data obtained in children with medulloblastomas, who presented between January 1987 and August 1998, were retrospectively reviewed. Images were termed surveillance if they were follow-up studies and symptom prompted if they were obtained to investigate new symptoms. One hundred seven patients (mean age 6 years and 3 months, range 2 months-15 years and 6 months) were entered into the study. Fifty-three children experienced tumor recurrence; 41 had one recurrence, nine had two, and three had three recurrences. Surveillance imaging revealed 10 of the first 53 recurrences and 15 of all 68 recurrences. When the first recurrence was identified by the emergence of symptoms (42 patients), the children tended to survive for a shorter time (hazard ratio 3.72, 95% confidence interval 1.42-9.76, p = 0.008) than children in whom the first recurrence was detected before symptoms occurred (10 patients). The median survival time following symptomatic tumor recurrence was 4 months and that after surveillance-detected tumor recurrence was 17 months. The median increased survival time among patients whose recurrence was asymptomatic and identified by imaging studies was 13 months, more than half the mean time between surveillance imaging sessions. Incomplete tumor resection was associated with a significantly reduced time to recurrence (p = 0.048) and to death (p = 0.002). The number of recurrences that were experienced was associated with a reduced time to death (p < 0.001).

CONCLUSIONS

Surveillance imaging is associated with an increase in survival in children with medulloblastomas. More frequent surveillance imaging in children with incomplete tumor excision and recurrent disease may further improve the length of survival.

Classifying the medulloblastoma: insights from morphology and molecular genetics

Significant advances in the treatment of the medulloblastoma (MB) have been made in the last 30 years, reducing mortality by 2-fold. Further improvements in the cure rate require an increased understanding of the biology of MBs, and this will translate into refinements in their classification. Scrutiny of the cytological variation found among MBs has recently led to the concept of the anaplastic MB, which overlaps the large-cell variant and appears to share its poor prognosis. In contrast, the MB with extensive nodularity, a distinctive nodular/desmoplastic variant occurring in infants, has a better outcome than most MBs in these young patients. Building on cytogenetic studies that have drawn attention to abnormalities on chromosome 17 in over a third of MBs, research shows non-random losses on chromosomes 8, 9, 10, 11 and 16, and gains on chromosomes 1, 7 and 9. Overexpression of ErbB2 receptors and losses on chromosome 17p have been proposed as independent indicators of aggressive behaviour, while high TrkC receptor expression indicates a favourable outcome. There is a strong association between anaplastic/large-cell tumours and MYC amplification, which has previously been linked with aggressive disease, but associations between abnormalities on chromosome 17 and anaplastic/large-cell MBs and between abnormalities in the shh/PTCH pathway and the desmoplastic variant are more controversial. Classification of the MB histopathologically and according to profiles of molecular abnormalities will help both to rationalize approaches to therapy, increasing the cure rate and reducing long-term side-effects, and to suggest novel treatments.