Progressive Multifocal Leukoencephalopathy in AIDS: Proton MR Spectroscopy Patterns of Asynchronous Lesions Confirmed by Serial Diffusion-Weighted Imaging and Apparent Diffusion Coefficient Mapping

Progressive multifocal leukoencephalopathy (PML) is a rare disease that occurs mainly in immunocompromised patients. Despite the progressive nature of the disease, the changes on MRI during the disease course - which may help in monitoring the disease process - have seldom been reported. Here we describe a patient with polymerase-chain-reaction-proven PML examined using serial diffusion-weighted imaging (DWI) and apparent-diffusion-coefficient mapping. Magnetic resonance spectroscopy (MRS) revealed that the demyelinating process was more active without significant neuronal loss at the newer and advancing edge of a lesion than in the older central part of the lesion. This case shows that MRI findings such as DWI and MRS may improve the diagnosis and the understanding of the pathophysiology of PML

Intracranial Dural Metastasis of Ewing's Sarcoma: a Case Report

Although intracranial dural metastasis of Ewing's sarcoma is a very rare finding, its imaging characteristics are similar to those of its primary form in the central nervous system. Thus, this tumor must be considered in the differential diagnosis of extra-axial dural masses

mRNA quantification and clinical evaluation of telomerase reverse transcriptase subunit (hTERT) in intracranial tumours of patients in the island of Crete

Telomerase is a reverse transcriptase that maintains telomeres by adding telomeric TTAGGG repeats to the ends of human chromosomes. The aim of this study was to evaluate quantitatively the mRNA expression of telomerase catalytic subunit (hTERT) in different types of intracranial tumours in relation to their histologic pattern and grade and correlate it with progression-free (PFS) and overall survival (OS) of patients. Human telomerase reverse transcriptase mRNA levels were estimated by the use of real time RT–PCR in 68 samples of intracranial tumours. It revealed statistical correlation between hTERT mRNA expression levels and the grade of the tumours (P<0.001). Patients having negative expression of hTERT mRNA had statistically longer PFS (P=0.031) and OS (P=0.047). Cox univariate regression analysis revealed that hTERT mRNA-positive patients had a high and statistically significant risk of relapse (hazard ratio (HR) of 2.24 and P=0.038). In the Cox multivariate regression model, the levels of hTERT mRNA were adjusted for tumour grade and patients age, and since there was statistically significant relationship between the levels of hTERT mRNA and the grade of the tumours (P=0.003 or P=0.006, respectively), hTERT mRNA levels could not be considered as an independent prognostic factor for PFS or OS

Prognostic Implication of Telomerase Activity in Patients with Brain Tumors

Telomerase adds telomeric repeats to the ends of telomeres to compensate for their progressive loss. A favorable prognosis is associated with low or no telomerase in some tumors. The authors investigated whether telomerase activity is associated with survival of patients with brain tumors. Sixty-two consecutive patients with brain tumors underwent surgery, and their surgical specimens were investigated. The patients were pathologically categorized as group I (aggressive group) and group II (non-aggressive group). Telomerase activity was examined by the telomeric repeat amplification protocol (TRAP) assay. The median time was calculated in association with overall survival and progression-free survival in each group. The significant difference was noted in telomerase activity between high-grade gliomas and low-grade gliomas (p=0.022). Telomerase activity was significantly associated with the median overall survival and progression-free survival in all tumors of the aggressive group. On the other hand, the median overall survival in the non-aggressive group was not dependent on telomerase activity, while the median progression-free survival was. Our data suggests that telomerase is an important prognostic indicator of survival in patients with brain tumors