Idiopathic granulomatous encephalitis mimicking malignant brain tumor.

Idiopathic granulomatous encephalitis is a rare disorder of unknown etiology, undetermined treatment, and often grave prognosis. This article describes a 4-year-old female who presented with a single focal febrile convulsion followed a few weeks later by right-sided hemiparesis. A huge infiltrative cerebral mass tumor was found which proved to be a granuloma on histologic study. Despite a thorough evaluation, including tissue studies and search for an infectious agent, no etiology could be identified, and the final diagnosis was idiopathic granulomatous encephalitis. Recurrent resections and high-dose steroid treatment failed to control the process, and the patient died of disease 6 months after presentation. Evaluation and treatment of idiopathic granulomatous encephalitis should be aggressive, and the possibility of chemotherapy and perhaps even radiotherapy should be considered if there is no response to steroids.

Role of MRI in the management of children with diffuse pontine tumors: a study of 15 patients and review of the literature.

BACKGROUND: Pontine tumors carry the worst prognosis of all brain tumors. In most cases, the diagnosis is based solely on MR imaging, without biopsy. OBJECTIVE: To describe the MR findings of pontine tumors at diagnosis and during follow-up and correlate those with prognosis and to assess the value of MR imaging in patient management compared to clinical evaluation. MATERIALS AND METHODS: Ninety-one MR scans of 15 children with diffuse pontine tumors were reviewed at diagnosis and during follow-up. The parameters analyzed were as follows: tumor extent, area, and volume; encasement of the basilar artery; presence of exophytic component; necrosis; cysts; hydrocephalus; and intensity and enhancement. Findings were correlated to length of progression-free and overall survival. Trends of amelioration or worsening on imaging were compared with the clinical findings. RESULTS: Median length of progression-free survival was 10 months, and median survival was 20 months. Only hydrocephalus at presentation was associated with shorter progression-free survival (P=0.02). On the last examination of each patient, the craniocaudal diameter was significantly greater than at diagnosis (P=0.03). The concordance between the imaging and the clinical findings was good. CONCLUSION: MR is the mainstay for the diagnosis and management of pontine tumors. Cranial growth seems to be an ominous sign. However, the prognostic value of MR is limited. MR findings correlate well with the clinical examination.

ATM gene mutations are not involved in medulloblastoma in children.

Primitive neuroectodermal tumors (PNET)-medulloblastomas account for approximately 20% of all brain tumors in children. Ataxia-telangiectasia is an autosomal recessive neurological disorder with predisposition to cancer. The most common neoplasms are lymphoid malignancies and solid tumors, including central nervous system tumors, astrocytomas, and medulloblastomas. To investigate the potential role of the ATM gene in the pathogenesis of medulloblastoma, 13 tumors were screened for ATM mutations and 9 for loss of heterozygosity (LOH) of the ATM locus and flanking regions. In none of the tumors were mutations identified. In five of them, the well-known polymorphisms D1853N and F858L were identified and in all 22 tumors, the wild-type allele was preserved. The frequency of the polymorphisms was similar to that reported in our and other normal populations. The LOH of the 11q region (including the ATM gene), detected in 25% of informative cases, is consistent with the molecular and cytogenetic reports of deletion of chromosome 11 in 13%-41% of medulloblastomas. These results indicate that mutations in the ATM gene do not play a role in the pathogenesis of medulloblastoma in children. The LOH in the 11q region may suggest hidden unidentified tumor suppressor genes that may be involved in the malignant transformation.