Favored gyral sites of supratentorial astrocytic tumors

It is well known that the predilective sites of extrinsic tumors (meningiomas, chordomas, etc) are at the skull base and along the calvarium. Although intrinsic tumors or glial tumors have also been seen to have anatomic and functional predilective sites within the central nervous system, these have not been well documented. We conducted this study to investigate if supratentorial astrocytic tumors have a predilection for specifi c gyri. We investigated the clinical and radiological records of 60 successive patients who had been operated on at our institution and had had histologically confi rmed supratentorial astrocytic tumors (36 males, 24 females, mean age: 52 years). Coronal sections were selected from the pre-operative contrast enhanced T1-weighted magnetic resonance imaging (MRI). The labeling of gyral areas for analysis of MRI was done using Yaşargil’s method. Additional information obtained from 3-dimensional MRI and surgical fi ndings was taken into account when it was diffi cult to distinguish the specifi c gyrus in which the tumor was located. The middle portions of the frontal gyri, insular gyri and the supramarginal gyrus and its surroundings were among the most common locations for the development of tumors. Interestingly, with the exception of one case, none of the tumors was situated in the precentral or postcentral gyri. It seems that supratentorial astrocytic tumors have a predilection for specifi c gyri and disfavor some other gyri. This cannot be explained simply by the different sizes of the cerebral lobes. A classical lobar concept of cerebral anatomy may lead to a misunderstanding of cerebral pathophysiology. Neurology Asia 2011; 16(1) : 71 – 79 Address correspondence to: Dr. Naci Balak, Department of Neurosurgery, Göztepe Education and Research Hospital, Kadiköy, ISTANBUL 34730, Turkey. Tel: +90 532 281 24 95, Fax: +90 216 455 30 88, Emails: [email protected], [email protected] INTRODUCTION It is well known that the predilective sites of extrinsic tumors (meningiomas, pituitary adenomas, chordomas, glomus jugulare tumors, epidermoids, etc) are at the skull base and along the calvarium. Although intrinsic tumors or glial tumors have also been seen to have anatomic and functional predilective sites within the central nervous system, these have not been well documented. Today, in spite of progress in understanding the molecular genetics of gliomas, the cell type(s) of origin are still uncertain, and the molecular determinants of disease aggressiveness are not well-understood. For example, whereas high-grade gliomas account for the majority of cerebral intra-parenchymal lesions in adults, low-grade gliomas account for the overwhelming majority of such tumors in children. Pediatric high-grade gliomas have also been reported to differ from their adult counterparts in terms of molecular abnormalities. As another example, high-grade astrocytomas comprise only 6-11% of all spinal cord gliomas and are even less common in children and the molecular biology of pediatric astrocytomas differs according to location. Studies using magnetic resonance imaging (MRI) of the brain were fi rst published in the literature in the 1980s. The routine use of MRI in clinical practice worldwide came later. Highresolution magnetic resonance imaging became the imaging modality of choice for investigation of central nervous system neoplasms in the 1990s. Thus, surgically relevant descriptions of the sulcal anatomy in radiological studies have until recently been lacking. Brain mapping by functional neuroimaging, diffusion tensor imaging enabled a tumor resection with regard to functional boundaries. Nevertheless, physiological understanding of the brain is not possible without anatomical and histological knowledge. The objective of this study was to examine the impact of anatomy on clinico-pathological correlation in astrocytic tumors, one of the most common Neurology Asia March 2011 72 primary tumors of the brain. As the fi rst step, we investigate if supratentorial astrocytic tumors have a predilection for specifi c gyri, using MRI and up-to-date gyral labeling in neuroanatomy.