LOW O6-METHYLGUANINE-DNA METHYTRANSFERASE (MGMT) AND PAN-CYTOKERATIN (PAN-CK) EXPRESSION VIA IMMUNOHISTOCHEMISTRY IN PITUITARY ADENOMAS.

INTRODUCTION: Pituitary adenomas (PA) are the third most common intracranial tumors, with an incidence rate of 10-15%. More than half are invasive, infiltrating adjacent structures. The primary objective of this project was to determine whether MGMT expression is associated with the invasiveness of PA. MATERIAL AND METHOD: All patients who underwent surgical decompression consecutively between 2007-2012 were included. All data were obtained from the case records. Formalin-fixed paraffin-embedded (FFPE) tissue specimens were stained with hematoxylin and eosin (HE) and then examined via light microscope. Paraffin blocks that lacked necrosis and hemorrhage were chosen for histologic examination. In addition to an immunoprofile battery that consisted of Ki-67 and p53, MGMT, S-100 and Pan-CK were evaluated as well. RESULTS: The subjects included 25 women and 15 men. The mean age was 48.9 ± 14.5 years. Of these, 63% of cases involved the invasion of adjacent structures. Of the PA, 17 (42%) were non-functioning pituitary adenomas (NFPA). There was a statistically significant relationship between the invasiveness and Ki-67, p53, MGMT expression, and prolactinoma. Gonodotropinomas were mostly non-invasive. FPAs presented invasive features more frequently than NFPAs. Pan-CK was positive in GH-secreting adenomas but negative in FSH- and LH-secreting adenomas. CONCLUSION: Ki-67 and p53 in lower expression level can be used for evaluating invasiveness but not for recurrence. MGMT expression can be a useful IHC indicator for invasiveness. However, Pan-CK cannot be used for invasiveness or aggressiveness.

Diagnostic approach to reveal retroperitoneal injury during lumbar discectomy.

For decades, lumbar discectomy has been one of the most common surgical practices performed by neurosurgeons. Although it has proved to be an effective and safe surgical procedure, life threatening complications may occur in rare cases, including iliac artery and/or vein injuries, superior rectal artery injury, common iliac artery aneurysms, iliac arteriovenous fistula, intestinal injuries, and ureteral injuries. Ureteral damage during the lumbar L4-5 microdiscectomy was reported in a slim 50 year-old male patient. Because of a small amount of bleeding occurred during the surgery as soon as the patient came out of anesthesia, an angio-computed tomography (CT) of the abdomen was performed. It showed no hematoma and no major vascular injury, but air bubbles were seen in the retroperitoneal region, indicating that perforation had occurred. The patient was then monitored carefully for immediate and possible subsequent injuries, in this way; ureteral damage was found and repaired. This is perhaps the first such case report in the literature of the early detection of ureteral damage using an angio CT scan. If there is a suspicion of perforation of the anterior annulus fibrosus and anterior longitudinal ligaments but no indication for an emergency laparotomy, an abdominal angio CT done immediately after the surgery and an abdominal non-contrast CT 4 hours later will give sufficient information concerning the potential occurrence of nearly all the major complications associated with lumbar discectomy.