No abstract

Classical fiber dissection of post mortem human brains enables us to isolate a fiber tract by removing the cortex and overlying white matter. In the current work, a modification of the dissection methodology is presented that preserves the cortex and the relationships within the brain during all stages of dissection, i.e. 'cortex-sparing fiber dissection'. Thirty post mortem human hemispheres (15 right side and 15 left side) were dissected using cortex-sparing fiber dissection. Magnetic resonance imaging study of a healthy brain was analyzed using diffusion tensor imaging (DTI)-based tractography software. DTI fiber tract reconstructions were compared with cortex-sparing fiber dissection results. The fibers of the superior longitudinal fasciculus (SLF), inferior frontooccipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF) and uncinate fasciculus (UF) were isolated so as to enable identification of their cortical terminations. Two segments of the SLF were identified: first, an indirect and superficial component composed of a horizontal and vertical segment; and second, a direct and deep component or arcuate fasciculus. The IFOF runs within the insula, temporal stem and sagittal stratum, and connects the frontal operculum with the occipital, parietal and temporo-basal cortex. The UF crosses the limen insulae and connects the orbito-frontal gyri with the anterior temporal lobe. Finally, a portion of the ILF was isolated connecting the fusiform gyrus with the occipital gyri. These results indicate that cortex-sparing fiber dissection facilitates study of the 3D anatomy of human brain tracts, enabling the tracing of fibers to their terminations in the cortex. Consequently, it is an important tool for neurosurgical training and neuroanatomical research.

Astroblastoma is one of the rarest tumors of the central nervous system (CNS), and its classification, histogenesis, diagnosis and therapeutic management are still being debated. The typical histopathological appearance is the perivascular, astroblastic pseudorosette, which is however present in other CNS tumors. To clarify the clinical, radiological, histopathological, prognostic and therapeutic characteristics, which have been treated only recently and are not well established yet due to the rarity of this tumor, six cases of histologically proven astroblastoma were retrospectively analyzed in light of more pertinent literature and paying special attention to therapeutic remarks. Between 1996 and 2005, six patients with cerebral astroblastoma were surgically treated at the Department of Neurosciences-Neurosurgery of Sapienza University in Rome. In three cases the lesion was termed low-grade astroblastoma, and high grade in the other three, according to current standard parameters. Median age of the six patients was 36 years. The time to diagnosis ranged from 1 week to 18 months. The radiological and anatomopathological features of this lesion are described. Surgical removal was total in four cases and subtotal in two. All patients received radiotherapy: two also had chemotherapy with temozolomide (TMZ). The three patients with low-grade astroblastoma are still alive today after a follow-up of 2, 5 and 19 years, respectively. Of the three patients with high-grade lesions, one is still alive after a 7-year follow-up, while the other two survived for 17 months (progression time 15 months) and 35 months (progression-reoperation time 23 months), respectively. Conclusions radical surgical resection is the treatment of choice for astroblastomas. Radiotherapy may play an adjuvant role in the treatment of high-grade lesions. The role of chemotherapy is still very debatable. We propose an aggressive standardized treatment for those lesions that meet anaplastic criteria, owing to their postulated glial origin and the propensity to have aggressive courses, and we advocate the use of a safe adjuvant chemotherapeutic regimen with TMZ, used concomitantly and subsequently to radiotherapy, especially for the high-grade astroblastoma cases. Multicenter studies, taking into account molecular biological findings, are necessary to define a common therapeutic strategy for astroblastomas.

Not all Glioblastoma multiforme (GBM, grade IV WHO) manifest the same clinical course. Different prognostic classes may arise from different morphologic and genetic profiles. The observation of oligodendroglial foci within GBM samples and their correlation with genetic alterations may predict a better prognosis. 450 patients affected by histologically proven supratentorial cerebral GBM were treated at our institutions from January 2000 to December 2006: all patients received at least subtotal surgical removal, followed by the same standard radio-chemotherapy adjuvant treatment. In a subgroup of 36 patients (8.0%) an oligodendroglial component was observed. Molecular assessment of these cases was performed and LOH for 1p, 19q and 10q, EGFR amplification and TP53 gene expression was determined. Median age of this subgroup was 52.1 years (range: 29-78 years) vs 62.4 years in the entire GBM population. Chromosome analysis resulted as follows: LOH 1p and/or 19q in 27 cases (75.0%), LOH of 10q in 21 cases (58.1%), EGFR amplification in 14 cases (39%) and TP53 mutation in eight patients (22.2%). OS was of 20.9 months while it was 13.6 months in the entire GBM population. Progression free survival (PFS) was 10.3 months and 7.6 months the entire group. Two-year survival was of 55%. The presence of an oligodendroglial component in GBM appears to be an important prognostic factor to which better prognosis can be related. LOH 1p and 19q was significantly associated with GBM with oligodendroglial component.