Glioblastoma occurring at the site of a previous medulloblastoma following a 5-year remission period.

We describe a case of a 14-year-old boy who developed a cerebellar and brainstem glioblastoma 5 years after treatment for a medulloblastoma. The patient first presented in 2003 with 9 months of vomiting and a 9-kg weight loss. A head MRI showed a heterogeneously enhancing posterior fossa mass with hydrocephalus. Gross total resection was performed and the tumor was consistent with a classic medulloblastoma. Postoperative chemotherapy and craniospinal radiation was administered. The patient remained tumor-free until 2008, at which time he presented with right-sided weakness and numbness, left eye pain, vomiting and weight loss. Imaging showed abnormalities within the posterior pons, medulla, inferior cerebellar peduncles, cerebellar hemispheres and cervicomedullary junction with expansion of the medulla and cervical spinal cord. Due to the location of the lesion, biopsy was felt to be too risky and was avoided. Despite receiving chemotherapy, his symptoms continued to worsen and he died 4 months later. Post mortem examination limited to the brain and spinal cord confirmed the radiographic extent of the tumor. Microscopic examination showed a highly cellular infiltrative glial neoplasm with extensive palisading necrosis. A diagnosis of glioblastoma was rendered. The question of whether the first and second tumors were related is of potential clinical and academic interest. The first tumor was synaptophysin-positive and GFAP-negative, consistent with medulloblastoma. The second tumor was synaptophysin-negative and focally GFAP-positive, consistent with glioblastoma. The glioblastoma displayed EGF receptor amplification, and interestingly, it also displayed MYCN amplification; both tumors showed low level PTEN deletion. The medulloblastoma displayed a signal pattern consistent with an isochromosome 17q, while the glioblastoma showed some cells with an isochromosome 17q signal pattern amid a background of cells with abundant chromosomal instability. The relationship between these two tumors, particularly with regard to various molecular events, is discussed.

A 61-year-old woman with osteomalacia and a thoracic spine lesion.

Phosphaturic mesenchymal tumor, mixed connective tissue variant (PMT-MCT) is a rare, largely benign, mesenchymal neoplasm almost invariably associated with oncogenic osteomalacia. It is generally found in the soft tissue and bone of the extremities. We report a case of a 61-year-old female with long-standing osteomalacia who was found to have PMT-MCT of the thoracic spine. There have been very few previously reported cases of PMT involving the spinal vertebrae and neuropathologists should be aware of this lesion. Recognition of PMT-MCT is critical for optimal patient care since complete surgical resection without additional therapy is curative.

A 41-year-old woman with von Hippel-Lindau and a cerebellar lesion.

A 41-year-old woman with a 12-year history of von Hippel-Lindau disease presented with progressive quadriparesis and difficulty swallowing. MRI revealed a well-circumscribed, partially cystic cerebellar neoplasm, consistent with hemangioblastoma. The tumor was resected and the diagnosis of hemangioblastoma confirmed. Embedded within the hemangioblastoma was a small focus of metastatic renal cell carcinoma (RCC). RCC metastatic to a CNS hemangioblastoma is the second most common type of tumor-to-tumor metastasis, which may be due to a number of factors. Proper immunostaining panels are required to clearly identify these cases since both tumor may have similar histology.

Anaplastic astroblastoma presenting as massive, sudden-onset, intraparenchymal hemorrhage.

Astroblastoma is a rare primary glial tumor of children and young adults, typically located in the cerebral hemispheres and presenting as a well-circumscribed, nodular, often cystic enhancing mass. The existence of astroblastoma as a distinct clinicopathologic entity has long been debated but is recognized in the 2007 WHO classification of CNS tumors. The grading of these tumors remains unsettled. Currently, no grade has been established and there are no clearly defined diagnostic criteria for low- or high-grade tumors. Astroblastomas in general are thought to have a favorable outcome with low rates of recurrence following gross total resection. We report a case of astroblastoma with 'high-grade/anaplastic' histology in a 12-year-old, previously healthy girl. The patient experienced severe, sudden-onset headache, and quickly became comatose. Head CT showed a massive intraparenchymal hemorrhage in the right frontal lobe with surrounding edema. She underwent emergent posterior frontal craniotomy for decompression and hematoma evacuation. Pathologic examination revealed a sharply demarcated hemorrhagic heterogeneous glial tumor with focal papillary architecture, densely hyalinized blood vessels, and intensely GFAP-positive perivascular cells. The tumor showed unequivocal high-grade features including an elevated proliferative index. The diagnosis of anaplastic astroblastoma was rendered. The patient expired on postoperative day 30. This case illustrates the potential poor outcome of high-grade astroblastoma and highlights the morphologic heterogeneity of this rare neoplasm.

Accuracy of contrast-enhanced MDCT and MRI for identifying the severity and cause of neural foraminal stenosis in cervical radiculopathy: a prospective study.

OBJECTIVE: The purpose of this study was to determine the accuracy of IV contrast-enhanced MDCT and MRI for evaluation of the severity and cause of neural foraminal stenosis in patients with cervical radiculopathy. SUBJECTS AND METHODS: Eighteen patients with cervical radiculopathy prospectively underwent contrast-enhanced MDCT and MRI. Contrast-enhanced MDCT scans were acquired at 1-mm thickness and reconstructed in oblique axial (parallel to disk) and sagittal (perpendicular to neural foramen) 2-mm sections without a gap. The MRI sequences used were sagittal T1-weighted, fast spin-echo T2-weighted, 3D fast spin-echo T2-weighted, axial T2-weighted, and 3D gradient-recalled echo. Three neuroradiologists independently and blindly rated the severity and cause of neural foraminal stenosis on a 4-point scale. Using the same scale at surgery, one of three surgeons rated the severity and cause of neural foraminal stenosis, and the results were used as the reference standard. Interobserver and intraobserver agreement (kappa) was calculated. RESULTS: For severity of neural foraminal stenosis, the sensitivities of contrast-enhanced MDCT (50/55, 91%) and MRI (55/57, 96%) were similar, as were their specificities (contrast-enhanced MDCT, 13/24, 54%; MRI, 11/24, 46%). For cause of neural foraminal stenosis, the accuracies of contrast-enhanced MDCT (46/54, 85%) and MRI (45/57, 79%) were similar. Interobserver agreement on severity of neural foraminal stenosis was moderate to almost perfect for contrast-enhanced MDCT (kappa=0.50-1.00) and MRI (kappa=0.43-1.00). For cause of neural foraminal stenosis, interobserver agreement was moderate to substantial for contrast-enhanced MDCT (kappa=0.52-0.76) but only fair for MRI (kappa=0.23-0.39). Intra observer agreement was very high for severity of neural foraminal stenosis (contrast-enhanced MDCT, kappa=0.85; MRI, kappa=0.80) and cause of neural foraminal stenosis (contrast-enhanced MDCT, kappa=0.86; MRI, kappa=1.00). CONCLUSION: Contrast-enhanced MDCT is as accurate as MRI in evaluation of the severity and cause of neural foraminal stenosis and may have better interobserver agreement.

Diffusion-weighted imaging characteristics of primary central nervous system germinoma with histopathologic correlation: a retrospective study.

RATIONALE AND OBJECTIVES: The aim of this study was to quantify, using diffusion-weighted magnetic resonance imaging, the microscopic rate of water diffusion in pure germinoma and to determine whether or not the apparent diffusion coefficient (ADC) values correlated with the different histologic components. MATERIALS AND METHODS: A retrospective analysis of echoplanar diffusion-weighted magnetic resonance images was conducted on 10 patients with 11 germinoma lesions. All images were obtained using 1.5-T magnets with a b value of 1000 s/mm(2). Regions of interest were drawn separately within the solid and the cystic or necrotic components of each germinoma, as well as within the normal gray and white matter of the respective cases, to calculate ADCs. The diffusion characteristics of the germinomas were assessed using mean and normalized ADC values. Histologic samples from all cases were blindly reviewed and then correlated with the ADC values. RESULTS: Data are expressed as mean +/- standard error. Evaluation of the solid components revealed that 36% of germinomas (4 of 11) had predominantly restricted diffusion (ADC(solid), 694.71x10(-6)+/-74.54x10(-6) s/mm(2); ADC ratio, 0.84+/-0.07) compared to normal brain. The majority (55% [6 of 11]) had normal diffusion (ADC(solid), 947.64x10(-6)+/-54.38x10(-6) s/mm(2); ADC ratio, 1.14+/-0.10). Only 9% (1 of 11) had increased diffusion (ADC(solid), 1172.30x10(-6)+/-48.52x10(-6) s/mm(2); ADC ratio, 1.67+/-0.16). The cystic and necrotic components had a mean ADC ratio of 2.55+/-0.25. There was no significant correlation between the histologic components and the ADC values of germinomas. CONCLUSIONS: The vast majority of germinomas demonstrated predominantly restricted (36%) or normal (55%) diffusion. The histologic components were not correlated with the ADC values.

Medulloblastoma mimicking Lhermitte-Duclos disease on MRI and CT.

BACKGROUND: Although previous reports purport that the unique magnetic resonance imaging (MRI) features of Lhermitte-Duclos disease (LDD) obviates the need for biopsy, medulloblastoma can have an indistinguishable imaging appearance. CASE DESCRIPTION: We present a patient who suffered from a medulloblastoma that demonstrated no enhancement and had imaging characteristics that were indistinguishable from LDD. This atypical imaging appearance, which could potentially be confused with LDD, may lead to misdiagnosis and inappropriate treatment in the absence of tissue sampling. CONCLUSION: In those patients where imaging is highly suggestive of LDD but lack other manifestations of Cowden syndrome, biopsy is required and advanced imaging with magnetic resonance spectroscopy (MRS) should be strongly considered.

Multichannel computed tomography angiography and its role in the evaluation of rotational vertebrobasilar insufficiency.

We present a case of rotational vertebrobasilar insufficiency diagnosed and followed by computed tomography angiography. Diagnosis of this entity provides a unique challenge in that the patient must be positioned properly to avoid a false-negative result without causing ischemic brain injury. The evaluation of rotational vertebrobasilar insufficiency with computed tomography angiography has never been described in the literature to the best of our knowledge. We highlight the advantages of using this technique in the diagnosis and follow-up of this uncommon entity.

Multichannel CT: evaluating the spine in postoperative patients with orthopedic hardware.

Evaluating the spine in patients with metal orthopedic hardware is challenging. Although the effectiveness of conventional computed tomography (CT) can be limited by severe beam-hardening artifacts, the evolution of multichannel CT in recent years has made available new techniques that can help minimize these artifacts. Multichannel CT allows faster scanning times, resulting in reduced motion artifacts; thinner sections, with which it is possible to create a scanned volume of isotropic voxels with equivalent image resolution in all planes; and the generation of a higher x-ray tube current, which may result in better penetration of metal hardware and reduction of artifacts. Although 140 kVp and high milliamperage-second exposure are recommended for imaging patients with hardware, caution should always be exercised, particularly in children, young adults, and patients undergoing multiple examinations. The acquisition of multiplanar reformatted images in the axial, sagittal, coronal, and oblique planes and of three-dimensional volume-rendered images optimizes image interpretation. Wide window settings are best for reviewing images when hardware is present. The integrity of hardware is best assessed with multiplanar average intensity projection. Soft-tissue structures are best visualized by interactively varying the window width and level settings. Implementation of these techniques can yield diagnostic-quality images and aid in patient treatment.