Cerebellar neoplasms in children

Cerebellar glioblastoma multiforme presenting as hypertensive cerebellar hemorrhage: case report

Background Cerebellar glioblastoma multiforme (GBM) is rare and presents with increased intracranial pressure and cerebellar signs. The recommended treatment is radical resection, if possible, with radiation and chemotherapy.

Clinical Presentation A 53-year-old man presented with hypertensive cerebellar bleeding and a 2-day history of severe headaches, nausea, vomiting, gait instability, and elevated blood pressure. Computed tomography (CT) showed a left cerebellar hematoma with no obstruction of cerebrospinal fluid and no hydrocephalus. CT angiography showed no signs of pathologic blood vessels in the posterior cranial fossa. The patient was observed in the hospital and discharged. Subsequent CT showed complete hematoma resorption. Two weeks later, he developed headaches, nausea, and worsening cerebellar symptoms. Magnetic resonance imaging (MRI) showed a 4-cm diameter tumor in the left cerebellar hemisphere where the hemorrhage was located. The tumor was radically resected and diagnosed as GBM. The patient underwent radiation and chemotherapy. At a follow-up of 1.5 years, MRIs showed no tumor recurrence.

Conclusion Hypertensive cerebellar hemorrhage may be the first presentation of underlying tumor, specifically GBM. Patients undergoing surgery for cerebellar hemorrhage should have clot specimens sent for histologic examination and have pre- and postcontrast MRIs. Patients not undergoing surgery should have MRIs done after hematoma resolution to rule out underlying tumor.

Imaging tumors of the pediatric central nervous system

Primary tumors of the central nervous system (CNS) are the second most common neoplasms in children and the leading cause of death in this patient population. The primary objective of this article is to describe the most common pediatric brain tumors and to offer an overview of their respective imaging features, primarily on magnetic resonance imaging. Precise anatomic characterization is essential for developing an appropriate differential diagnosis. Once equipped with this critical information, physicians should be better able to make firm diagnoses, leading to improved disease management and patient outcomes in the setting of CNS tumors of childhood.

Cerebellar glioblastoma multiforme in an adult

Primary cerebellar glioblastoma multiforme (GBM) is a rare tumor in adults that accounts for just 1% of all cases of GBM. Due to their rarity, cerebellar GBMs are not yet completely understood about the pathogenesis and the prognosis. Here, we present a case of GBM in a 69-year-old man. Neurologic examination revealed the presence of cerebellar signs. Magnetic resonance imaging (MRI) showed a 4.5 x 3.6 cm-sized, ill-defined, heterogeneously enhancing mass in the left cerebellum and two patchy hyperintense lesions in the right cerebellum with minimal enhancement. After operation, glioblastoma was histologically confirmed. Postoperative radiotherapy with concomitant and adjuvant temozolomide chemotherapy was subsequently followed. Here, a case of unusual GBM in the cerebellum is reported with review of literature regarding the pathogenesis, the differential diagnosis and prognosis. There was no evidence of recurrence during postoperative one year. This patient showed a good prognosis in spite of the multiple lesions.

Paediatric PNET: pre-surgical MRI features

AIM

To describe the preoperative magnetic resonance imaging (MRI) characteristics of primitive neuroectodermal tumours (PNETs), in particular the diffusion-weighted imaging (DWI), MR spectroscopy (MRS) features and cerebrospinal fluid (CSF) tumour dissemination.

MATERIAL AND METHODS

Twelve patients with PNETs were reviewed: nine with medulloblastoma and three with supratentorial PNETs (SPNETs). The MRI examination included contrast-enhanced intracranial and spinal MRI, and in some patients, gradient recalled echo, fluid-attenuated inversion recovery (FLAIR), DWI, and MRS.

RESULTS

All PNETs were either hypointense or isointense on T1-weighted images. Ten of the 12 tumours were either isointense or hypointense on T2-weighted images, and 11 were isointense on FLAIR images. Patients with SPNETs had large, vascular and haemorrhagic tumours. On DWI, all PNETs were hyperintense and had restricted apparent diffusion coefficient. MRS (two patients with medulloblastoma and one with a SPNET), showed elevated choline, decreased N-acetyl aspartate, and a small taurine peak in all three patients. Intraspinal tumour dissemination, visible as uniform or nodular enhancement coating the conus medullaris, was detected in six of 12 patients, two of whom also had intracranial dissemination.

CONCLUSION

PNETs have a characteristic imaging appearance on FLAIR, DWI and MRS, which may help in differentiating these highly cellular neoplasms from other tumours. There is CSF tumour dissemination in a high proportion of patients, and spinal imaging is important for disease staging and to formulate treatment protocols.

[Imaging of childhood brain tumors]

Brain tumors represent around a quarter of all solid tumors observed in the pediatric population. Infratentorial tumors are the most frequent, mostly encountered between 4 and 11 years of age. Early imaging is important because initial symptoms can be misinterpreted as statural and pubertal disorders or pseudoabdominal symptoms with apathy and vomiting in infants. Because signal abnormalities on MRI are most often not specific, it is essential to take into account the clinical and topographic characteristics of the lesion to establish an appropriate differential diagnosis. The main patterns of brain tumors observed in pediatrics are presented. Brain metastases are very unusual in children, in contrast to lepto-meningeal metastasis.

Atypical features of medulloblastoma on magnetic resonance imaging: case report and review of the literature

Magnetic resonance imaging (MRI) is the radiologic modality of choice used to evaluate suspected lesions in the posterior fossa, given its greater sensitivity compared with other neuroimaging techniques. The case of a 9-year-old girl with progressive ataxia is presented. MRI of the brain demonstrated nonspecific T2-weighted abnormalities involving the cerebellar vermis with minimal mass effect suggested by asymmetric enlargement of the left superior cerebellar peduncle. Postgadolinium studies showed only minimal enhancement of the left superior cerebellar peduncle. After an MRI of the spine demonstrated drop metastases, a cerebellar biopsy was performed, which revealed an infiltrating medulloblastoma confined to the granular layer and leptomeninges. Hence, MRI is an important ancillary tool in the diagnosis of medulloblastoma, but caution needs to be taken when interpreting imaging studies.

Current therapy and new perspectives in the treatment of medulloblastoma

Medulloblastoma, a malignant tumor arising from the medullary velum, is the most common malignant brain tumor of childhood. Local extension into the cerebellar hemisphere, infiltration of the floor of the fourth ventricle, and seeding into the subarachnoid space are common. Early diagnosis and improved treatment consisting of surgery followed by radiation and chemotherapy for selected high-risk patients has contributed to a dramatic change in survival. This article reviews current treatment strategies and describes new therapies that have the potential to improve the outlook of children with medulloblastoma.

Review article: computed tomography and magnetic resonance in the diagnosis of intraventricular cerebral masses

We describe a series of 60 cases of patients with masses arising within the cerebral ventricles. The site and relative frequency is noted for each histological type. The differential diagnosis depends on patient age and sex, site, morphology and number of masses, presence and type of hydrocephalus and the characteristics of the mass on computed tomography (CT) and magnetic resonance (MR) images. A review of the literature has been performed and this information collated with our own experience to give detailed descriptions of the typical features of each intraventricular mass. Attention is drawn to intraventricular neurocytoma, a recently described tumour that may be mistaken histologically for intraventricular oligodendroglioma or ependymoma. A comparison is made of the value of CT and MR in the diagnosis of intraventricular masses.

False-positive MRI detection of recurrent or metastatic pediatric infratentorial tumors

Gadolinium-DTPA enhanced MRI is the modality of choice when imaging central nervous system infratentorial tumors in the pediatric population. The detection of a new enhancing lesion following initiation of therapy is typically considered pathognomonic for recurrent or metastatic tumor. We report two pediatric patients with infratentorial central nervous system tumors who demonstrated new areas of enhancement with gadolinium-DTPA enhanced MRI following initiation of multimodality therapy. Both patients had surgical biopsy of the new lesions with histologic review failing to demonstrate viable tumor. These studies suggest caution in considering new enhancing lesions detected by MRI in a child with a brain tumor pathognomonic for new sites of active tumor.