Chordoma is a rare tumor arising in the sacrum, clivus, or vertebrae. It is often not completely resectable and shows a high incidence of recurrence and progression with shortened patient survival and impaired quality of life. Chemotherapeutic options are limited to investigational therapies at present. Therefore, adjuvant therapy for control of tumor recurrence and progression is of great interest, especially in skull base lesions where complete tumor resection is often not possible because of the proximity of cranial nerves. To understand the extent of genetic instability and associated chromosomal and gene losses or gains in skull base chordoma, we undertook whole-genome single-nucleotide polymorphism microarray analysis of flash frozen surgical chordoma specimens, 21 from the clivus and 1 from C1 to C2 vertebrae. We confirm the presence of a deletion at 9p involving CDKN2A, CDKN2B, and MTAP but at a much lower rate (22%) than previously reported for sacral chordoma. At a similar frequency (21%), we found aneuploidy of chromosome 3. Tissue microarray immunohistochemistry demonstrated absent or reduced fragile histidine triad (FHIT) protein expression in 98% of sacral chordomas and 67%of skull base chordomas. Our data suggest that chromosome 3 aneuploidy and epigenetic regulation of FHIT contribute to loss of the FHIT tumor suppressor in chordoma. The finding that FHIT is lost in a majority of chordomas provides new insight into chordoma pathogenesis and points to a potential new therapeutic target for this challenging neoplasm.

Arachnoid cysts (ACs) are frequently found on intracranial imaging studies but intrasellar arachnoid cysts are rarely encountered. We present a 49-year old patient who had headaches for 6 months and cystic sellar mass was found in his cranial imaging. We operated him by transnasal transsphenoidal route. Our intraoperative diagnosis was an arachnoid cyst and pathologic studies verified our observation. He did well postoperatively and after a 1year follow-up he was left free from future follow-ups. As common cystic lesions occupying the sellar region can simulate ACs both clinically and radiologically, neurosurgeon can fail to include ACs in making the initial diagnosis preoperatively. Although a rare entity, arachnoid cysts should be considered in the differential diagnosis of sellar region.

Olfactory groove meningiomas make up 4 to 13% of meningiomas. The first line treatment of meningiomas is surgery, but the extent and types of approaches advised for olfactory groove meningiomas are diverse, from aggressive skull base approaches to standard or minimally invasive craniotomies and endoscopic approaches. We retrospectively reviewed our series of olfactory groove meningiomas that were operated microsurgically by standard pterional or unifrontal approaches. Our series of 61 olfactory groove meningioma patients operated through pterional or unifrontal approaches between March 1987 and September 2015 was reviewed and the clinical data, radiological findings, surgical treatment and clinical outcomes of the patients were retrospectively analyzed. Sixty-three craniotomies were performed in total. Pterional and unifrontal approaches were used in 38 (60.3%) and 25 (39.7%) surgical procedures, respectively. Overall, gross total tumor resection was achieved in 59 (93.7%) cases. Complications were seen in 8 cases, and 2 of these patients underwent reoperation. Three of the 4 patients where only subtotal resection could be achieved underwent gamma knife radiosurgery. Pterional and unifrontal approaches, which are familiar and standard for neurosurgeons, can accomplish high rates of total resection with acceptable complication and recurrence rates for the treatment of olfactory groove meningiomas.