Minimally invasive approach to management of pituitary adenomas.

Pituitary adenomas are the third most common benign intracranial tumor seen in neurosurgical practice. They represent >or= 15 % of all primary intracranial tumors with 25 % prevalence as reported in autopsy series. Advances in biomedical assays, imaging studies support their diagnosis and tailor their management. The direct endonasal transsphenoidal surgery is the recommended intervention for adenoma resection in more than 95 %. The safety and efficacy of this intervention was enhanced by microsurgery and more recently by the introduction of neuronavigation, assisted endoscopy and intraoperative MRI. Anticipation of clinical, biochemical, radiological and surgical pitfalls by a multidisciplinary team is of paramount importance in improving treatment and preventing potential complications.

Trans-eyebrow mini-orbitozygomatic pterional approach for minimally invasive skull base surgery.

Surgical treatment of skull base pathologies remains one of the most challenging tasks to neurosurgeons. Advances in neuroimaging as well as the evolution of modern techniques and neurosurgical equipment have paved the way for a more precise diagnosis, a better selection of the surgical approach and have prompted the adaptation of minimally invasive concepts to different aspects of modern neurosurgical practice. The trans-eyebrow mini orbitozygomatic pterional approach is a tailored approach that provides multiple avenues to the target, minimizing retraction of the brain and affords better exposure of the pathology. It was performed on 16 patients with frontobasal or suprasellar tumors. The post-operative clinical outcome was excellent with smooth and fast recovery as well as satisfactory cosmetic results. It should be considered as part of the armamentarium to manage skull base lesions when indicated and not to replace other well recognized skull base approaches.

Human ARHGDIG, a GDP-dissociation inhibitor for Rho proteins: genomic structure, sequence, expression analysis, and mapping to chromosome 16p13.3.

GDP-dissociation inhibitors (GDIs) play a primary role in modulating the activity of GTPases. We recently reported the identification of a new GDI for the Rho-related GTPases named RhoGDIgamma. This gene is now designated ARHGDIG by HUGO. Here, in a detailed analysis of tissue expression of ARHGDIG, we observe high levels in the entire brain, with regional variations. The mRNA is also present at high levels in kidney and pancreas and at moderate levels in spinal cord, stomach, and pituitary gland. In other tissues examined, the mRNA levels are very low (lung, trachea, small intestine, colon, placenta) or undetectable. RT-PCR analysis of total RNA isolated from exocrine pancreas and islets shows that the gene is expressed in both tissues. We also report the genomic structure of ARHGDIG. The gene spans over 4 kb and is organized into six exons and five introns. The upstream region lacks a canonical TATA box and contains several putative binding sites for ubiquitous and tissue-specific factors active in central nervous system development. Using FISH, we have mapped the gene to chromosome band 16p13.3. This band is rich in deletion mutants of genes involved in several human diseases, notably polycystic kidney disease, alpha-thalassemia, tuberous sclerosis, mental retardation, and cancer. The promoter structure and the chromosomal location of RhoGDIgamma suggest its importance and underscore the need for further investigation into its biology.

Medulloblastoma in adults.

Seventeen adult patients (16 years of age and over) with medulloblastoma were managed at King Faisal Specialist Hospital and Research Centre between 1981 and 1992. Nine patients were males and eight were females. The average age at diagnosis was 26.7 years; the females were younger than the males. The average duration of history before diagnosis was 14.5 weeks, the females presenting earlier than the males. The tumors were located in the midline (9) and the hemispheres (8). Nine patients had the desmoplastic variant and eight had standard primitive neuroectodermal tumor. Hydrocephalus developed in 14 of the patients only seven of whom required a shunting procedure. All patients had either subtotal or gross total removal of the tumor. Sixteen patients had postoperative radiation therapy; one patient refused radiation therapy. Two patients had chemotherapy following recurrence of the tumor. The clinical presentation, radiological studies, histological variants, treatment and outcome are discussed in this report.