CLINICAL CASE REPORT Gliomatosis cerebri

biopsy. Summary. Gliomatosis cerebri is a rare diffusely infiltrating glial tumor involving two or more lobes and is frequently is bilateral. Infiltrative extent of tumor is out of proportion to histological and clinical features. We present a case in which finally the diagnosis of gliomatosis cerebri was made. In this case, computed tomography showed that midline structures were insignificantly shifted to the left, there was a mild dilatation of lateral ventricles more expressed on the right, and no pathologic changes of brain tissue density were found. On magnetic resonance tomography, T2W/SE and T2W/FLAIR images revealed zones of hyperintense signal, spreading with time, through several lobes of the brain with no enhancement on T1W images. Diagnosis of gliomatosis cerebri was sus-pected, stereotaxic biopsy was performed, and pathological examination revealed changes typical of diffuse glial tumor. In this article, changes typical of gliomatosis cerebri seen in other radiological methods such as computed tomography, magnetic resonance spectroscopy, dynamic contrast-en-hanced T2*-weighted magnetic resonance, and positron emission tomography also are discussed.


Introduction
Gliomatosis cerebri (GC) is a diffusely infiltrating glial tumor involving two or more lobes and is frequently bilateral. Infiltrative extent of tumor is out of proportion to histological and clinical features (1).

Case report
A 43-year-old man complained of pain in the legs with shifting localization for 15 years and paroxysmal headache of various characters for several months, which subsided by itself or by changing position of the head. Clinical examination was unremarkable. The findings of laboratory tests were normal.
The patient was referred to the Department of Radiology for brain computed tomography. The midline structures were insignificantly shifted to the left. There was a mild dilatation of the lateral ventricles more expressed on the right. No pathologic changes of brain tissue density were found (Fig. 1). Then magnetic resonance imaging (MRI) of the brain was performed. At first, on T2W/SE and T2W/FLAIR images, zones of hyperintense signal and with no enhancement temporally in the right hemisphere including insular cortex were seen (Figs. 2 and 3). After two months on T2W/FLAIR images, these zones also appeared in the left hemisphere temporoanterobasally, frontobasally in me-    One of the accepted hallmarks is increased cellularity without destruction of the infiltrated parenchyma (4). There is no necrosis or neovascularity. There are two gross pathologic types: type I, neoplastic overgrowth, expansion of existing structures without circumscribed tumor mass; type II, a diffuse lesion with a focal neoplastic mass with malignant features (1). GC usually is WHO grade III, but also may be WHO grade II.
Although GC can occur at any age, it generally affects individuals in their third and fourth decades of life with no gender predominance (2).
GC may affect any part of the brain or even the spinal cord, optic nerve and compact white matter. Clinical manifestations are nonspecific and include headache, seizures, visual disturbances, corticospinal tract deficits, lethargy, and dementia (2, 5, 6). These symptoms are as a result of increased pressure within the head (headache and vomiting), as well as more localizing symptoms as a function of specific tumor location, rate of growth and associated in-flammation (weakness and other motor dysfunction, neuroendocrine abnormalities, changes in behavior or thought processes) (6). Rarely GC is complicated by hydrocephalus or herniation and extremely rarely by hemorrhage (1). Very rarely GC may present as a parkinsonian syndrome (7). Symptoms appear late since the tumor is slow-growing and does not disrupt the brain tissue until late. Personality changes are more common than focal signs (3).
On MRI, it typically appears as a diffuse, poorly circumscribed, infiltrating nonenhancing lesion that is hyperintense on T2-weighted images and expands the cerebral white matter (2). GC infiltrates, enlarges yet preserves underlying brain architecture. Typically, it involves hemispheric white matter, basal ganglia and thalami (75%), corpus callosum (50%), brainstem and spinal cord (10-15%), cerebellum (10%). MRI shows expanded hemisphere, with sulcal effacement and ventricular compression as well. Usually there is no enhancement on MRI until late in the course of the disease (1, 3).
MRI spectroscopy might be used to classify GC as a stable or progressive disease indicating its potential therapeutic relevance (8). GC shows a marked elevation of myo-inositol, normal or mildly increased choline, decreased N-acetyl-aspartate concentration. Diffusion tensor imaging shows the preservation of nerve fibers in GC compared with other tumors (1). Dynamic contrast-enhanced T2* weighted MRI shows a low relative cerebral blood volume, which correlates with lack of vascular hyperplasia. PET with FDG shows marked hypometabolism (1).
The diagnosis of GC should be confirmed by biopsy. The pathological grade of GC is not always established, because only a fraction of these tumors is biopsied (6).
GC can be mistaken for nonneoplastic white matter disease. It is difficult to distinguish GC from highly infiltrate anaplastic astrocytoma or glioblastoma multiforme (2).
Usually there is a relentless progression, and prognosis for GC is generally poor with a median survival time of 38 months. Surgery is not practical considering the extent of the disease, standard chemotherapy (nitrosourea) is shown to be unsuccessful, and although brain irradiation can stabilize or improve neurological function in some patients, its impact on survival has yet to be proven (1,2,5). Raktažodžiai: galvos smegenų gliomatozė, magnetinio rezonanso tomografija, stereotaksinė biopsija.