Correlation of Clinical and Immunohistochemical Diagnosis in Patients with Pituitary Adenomas

OBJECTIVES: Pituitary adenomas are common neurological lesions believed to account for 10% to 15% of all primary brain tumors. There can be diagnostic confusion due to discordance of the preoperative endocrine and the postoperative immunohistochemical diagnosis. In this study, the rate of discordance between preoperative and postoperative findings and their clinical implications were investigated. METHODS: From March 2005 to March 2006, 26 patients who underwent surgery for a pituitary adenoma were enrolled in this study. The preoperative pituitary hormone level and postoperative immunohistochemical results were compared and analyzed. RESULTS: The median age of the patients was 38 years (range 15-66 years). The male to female ratio was 8 to 18. The endocrine evaluation showed 16 hormonally-active and 10 hormonally-inactive adenomas. The immunohistochemical findings showed : 13 prolactin-positive, 1 GH-positive, 1 FSH-positive, 8 pleurihormone-positive and 3 stain-negative adenomas. The percentage of discordance observed between the preoperative endocrine and postoperative immunohistochemical diagnosis was 54%. Nine of 10 endocrine non-functioning adenomas showed : 3 PRL positive, 1 GH positive, 2 PRL+GH positive, 1 TSH+FSH positive, 1 FSH+ACTH+PRL positive and 1 FSH+LH+PRL positive adenomas by immunohistochemistry. Three endocrine PRL+GH secreting adenomas showed 2 PRL positive and 1 FSH+GH positive by immunohistochemistry. One endocrine PRL secreting and 1 GH secreting adenoma showed 1 PRL+TSH positive and 1 GH+PRL positive by immunohistochemistry, respectively. The diagnosis of the other 12 pituitary adenomas showed concordance. CONCLUSION: The results of this study showed 54% discordance rate between the preoperative endocrine and postoperative immunohistochemical diagnosis for pituitary adenomas.

Photochemically Induced Cerebral Ischemia in a Mouse Model

OBJECTIVE: Middle cerebral artery occlusion(MCAO) has widely been used to produce ischemic brain lesions. The lesions induced by MCAO tend to be variable in size because of the variance in the collateral blood supply found in the mouse brain. To establish a less invasive and reproducible focal ischemia model in mice, we modified the technique used for rat photothrombosis model. METHODS: Male C57BL/6 mice were subjected to focal cerebral ischemia by photothrombosis of cortical microvessels. Cerebral infarction was produced by intraperitoneal injection of Rose Bengal, a photosensitive dye and by focal illumination through the skull. Motor impairment was assessed by the accelerating rotarod and staircase tests. The brain was perfusion-fixed for histological determination of infarct volume four weeks after stroke. RESULTS: The lesion was located in the frontal and parietal cortex and the underlying white matter was partly affected. A relatively constant infarct volume was achieved one month after photothrombosis. The presence of the photothrombotic lesion was associated with severe impairment of the motor performance measured by the rotarod and staircase tests. CONCLUSION: Photothrombotic infarction in mice is highly reproducible in size and location. This procedure can provide a simple method to produce cerebral infarction in a unilateral motor cortex lesion. In addition, it can provide a suitable model for study of potential neuroprotective and therapeutic agents in human stroke.