Predictive role of magnetic resonance imaging in the distinction of isocitrate dehydrogenase (IDH) mutant grade 4 astrocytomas versus glioblastomas.

BACKGROUND: Isocitrate dehydrogenase (IDH) mutation status is a crucial prognostic factor in high-grade glial tumors. PURPOSE: To investigate whether magnetic resonance imaging (MRI) features can display a diagnostic performance in the determination of IDH mutation in high-grade gliomas. MATERIAL AND METHODS: A total of 170 patients including 24 IDH mutant grade 4 astrocytomas and 146 glioblastomas (GBM) were retrospectively examined via contrast-enhanced (CE) MRI before surgery. Immunohistochemistry and genomic sequence analyses were performed on specimen materials for the determination of IDH mutational status. Certain morphological and diffusion-weighted imaging (DWI) parameters were utilized to see if they could play a role to be non-invasive potential imaging predictors in the discrimination of IDH mutant versus wild-type (WT) high-grade gliomas. RESULTS: On histopathological examination, IDH mutation was detected in 24 patients with high-grade glioma and 146 of the patients were found to be WT. Certain morphological criteria of tumor location and involvement, tumor margins, visual detection of diffusion restriction on DWI, and quantitative apparent diffusion coefficient (ADC) parameters consisting of ADCmean, ADCmin, and ADCr could be used as imaging predictors in the discrimination of high-grade IDH mutant versus WT tumors. CONCLUSION: Certain MRI morphologic features and visual detection of diffusion restriction on DWI and quantitative ADC parameters consisting of ADCmean, ADCmin, and ADCr can be considered non-invasive, significant independent imaging predictors in the discrimination and can obviate invasive procedures for histopathological diagnosis.

Recurrent Solitary Fibrous Tumor in Intradural Extramedullary Space: Case Report and Review of the Literature.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare neoplasm arising from spindle cells and most commonly arising from pleura. Spinal SFT/HPC is a rare entity; hence, it is not on the top of the differential diagnosis list when a clinician faces a spinal lesion. In the review of the literature, there exist less than 50 case reports of intradural extramedullary SFT/HPC. Here, we present a 54-year-old female patient who underwent subtotal surgical excision of an intradural extramedullary spinal mass pathologically reported to be SFT/HPC and had symptomatic recurrence in the 3rd year of follow-up. Surgical intervention was unachievable and the patient was given 45 Gy to the surgical cavity followed by a 5.4 Gy boost to visible tumor with external radiotherapy. Patient reported significant relief of her symptoms. We aim to contribute to the formation of a treatment algorithm for this rare entity.

Evaluation of Human Epidermal Growth Factor Receptor 2 Overexpression, Clinicopathological Characteristics, and Factors Affecting Survival in Gastric Cancer.

OBJECTIVES: The objective of the study was to evaluate the human epidermal growth factor receptor 2 (HER2) overexpression, clinicopathological features, and factors affecting survival in patients with gastric cancer. METHODS: The study is a retrospective study conducted with 128 cases of gastric cancer who were admitted to Sisli Hamidiye Etfal Training and Research Hospital between 2005 and 2012. Patients' demographic characteristics, performance score, tumor localization, information about surgery, HER2 measurements, histopathological characteristics, stage, treatment features, metastasis sites, and overall survival time were obtained from medical records. Immunohistochemical analysis was performed for HER2 scoring. RESULTS: There were 89 (69.5%) men and 39 (30.5%) women in the study group, and the median age of the patients was 64 years. The median survival time of the patients was 24.43 months. The survival rate of the patients was calculated as 35.4±5.9%. Overall survival time was found to be shorter in the group with higher HER2 levels and also those with advanced-stage cancer. The survival rate was found to be significantly lower in patients with perineural invasion and advanced stage. However, the survival rate was not associated with lymphovascular invasion, surgical margin involvement, and HER2 levels. In the multivariate Cox Regression analysis performed to assess the effects of gender, histological subtype, stage, and surgical margin on overall survival, disease stage was found to be the only factor effective on survival. Gender, histological subtype, and the surgical margin did not affect prognosis. CONCLUSION: The survival rate in gastric cancers was found to be lower in those with advanced-stage disease. Higher HER2 level and the disease stage were associated with shorter overall survival time.

Influence of Human Telomerase Reverse Transcriptase Mutation on the Aggressiveness and Recurrence in Meningiomas.

BACKGROUND:  Over 200 human telomerase reverse transcriptase (hTERT) polymorphism combinations have been implicated in the development of cancer. This study aimed to evaluate hTERT mutations in meningioma tissue and its association with meningioma. MATERIAL AND METHODS: A total of 90 patients who underwent surgery between 2006 and 2015 and were histopathologically diagnosed with meningioma (WHO 2016) were included. RESULTS: Among the 90 participants included herein, 50 (55.5%) and 40 (44.5%) were female and male, respectively, with an average age of 56.2 ± 14 years. Mean Ki-67 values were 10.56% (SD 12.41, range 0-60), while the mean follow-up duration was 39.1 months (SD 26.3). Low- and high-grade patients had a mean Ki-67 score of 4.31% (SD 3.58, range 0-16) and 19.92% (SD 14.91, range 2-60) (p = 0.0001). Our results showed a moderate positive correlation between Ki-67 score and the presence of hTERT mutation (Pearson correlation test, r = 0.5161; p = 0.0001). Patients with an hTERT mutation > 30% had significantly higher risk for reoperation than those with lower levels of mutation (p = 0.016, chi square test). None of the patients requiring reoperation had an hTERT mutation < 10%. Moreover, high-grade patients had a 7.2 times higher risk of reoperation than those with an hTERT mutation > 30%. CONCLUSION: The presence of hTERT mutation, in addition to high Ki-67, indicated a more aggressive meningioma disease course and potentially increased risk of recurrence.

Relationships between androgen receptor expression and clinicopathological parameters in male breast cancer.

INTRODUCTION: Most patients with male breast cancer (MBC) express the androgen receptor (AR). AR expression in these tumors may have both prognostic and predictive values because its presence indicates the potential benefits of an anti-androgen therapeutic approach. The present study aimed to investigate the relationship between AR expression and clinicopathological parameters in MBC. MATERIAL AND METHODS: The data of 35 patients who received a histological diagnosis of MBC at the pathology department of our hospital between January 2007 and December 2017 were retrospectively reviewed. The patients' demographic data, follow-up records and pathology reports were recorded. AR expression status and its relationship with clinicopathological parameters were evaluated. The chi-square test was used to compare independent groups. Univariate survival analyses were performed using the Kaplan-Meier survival procedure. A p value of ≤0.05 was considered statistically significant. RESULTS: There was no significant relationship between AR expression and AJCC stage (p=0.585), pathologic stage (p=0.696), histologic grade (p=0.685), lymph-node status (p=0.685), survival rate (p=1.000), age(p=1.000), lymphovascular invasion (p=0.700), perineural invasion(p=1.000), skin invasion (p=1.000), nipple involvement(p=1.000), DCIS presence(p=1.000), ER positivity(p=1.000), PR positivity (p=0.218), Her2 expression (p=0.523), Ki67 index (p=0.685), Luminal A group (p=0.700), Luminal B group (p=0.691), triple negative group (p=1.000). CONCLUSION: Further investigation of the relation between AR expression and clinicopathological parameters of patients with MBC might yield important information and lead to the development of additional treatment options. KEY WORDS: Androgen receptor, AR expression, breast cancer, Male Breast cancer, Prognosis, Receptor status.

Male Breast Cancer with Radiological and Histopathological Findings.

OBJECTIVES: We aimed to remind and emphasize the importance of male breast cancer with radiological and histopathological results of the patients diagnosed in our institution. METHODS: Men who had proven breast cancer by histopathological analysis between February 2010-April 2018 were reviewed retrospectively. The mammographic, ultrasonographic, magnetic resonance and positron-emission-tomography imaging features and histopathological results of the masses were noted. RESULTS: Twenty-five men were included in this study. Mean age of the patients was 62.9 (min:42; max: 82) with a mean size of lesions was 26.4 mm (min:10 mm; max: 70 mm). All the lesions were presented as a palpable mass. According to imaging features of the five patients who had mammography, all the four patients were presented as a mass but one patient as asymmetrical density. According to imaging features of the 20 patients who had an ultrasound, 16 (80%) lesions were presented as hypoechoic solid masses with irregular margins, while four (20%) were presented as complex-cystic masses with irregular margins. All the patients were diagnosed as invasive ductal cancer with luminal subtype by histopathological analysis. CONCLUSION: Even at young ages, the palpable lesion may be the only symptom of male breast cancer. Male breast cancer is generally presented as retroareolar mass and detected in advanced stages, probably due to low awareness and lack of screening programme. Invasive ductal cancer is the most common type of male breast cancer with the luminal subtype.

Pseudoangiomatous stromal hyperplasia causing severe breast enlargement in a 15-year-old girl: A case report.

Pseudoangiomatous stromal hyperplasia (PASH), composed of proliferated stromal mesenchymal cells of myofibroblastic origin, is a benign lesion of the breast. A few cases associated with pseudoangiomatous stromal hyperplasia of the breast have been reported. We report this case of a 15-year-old girl with PASH accompanied by severe enlargement and painful mass in the right breast. There were no other palpable masses or lymph nodes. Biopsy of the mass showed histopathologic features characteristic of fibroadenoma. The palpable mass was around 6x5cm in diameter, while clinical manifestations aroused suspicion of malignancy mimicking sarcoma of the breast. Although, biopsy of the mass showed benign histopathologic features; surgical excision was performed because of the damage caused by enlarging breast tissue and clinical suspicion of malignancy.

Intraoperative Imprint-squash Methods in Central Nervous System Tumors.

OBJECTIVES: Central nervous system (CNS) tumors constitute 1.3% of all cancers in adults and are the seventh leading cause of death in developed countries. CNS tumors are very soft and have a gelatin-like texture. Smear technique is a very simple and fast method for the diagnosis of brain tumors. METHODS: In this study, we evaluated the imprint and squash cytology of 100 cases sent to the pathology clinic. The sections of the paraffin blocks were prepared after the operation in the neurosurgery clinic of the SBU Hamidiye Sisli Efal Training and Research Hospital. The accuracy rate was 90% in the differential diagnosis of malignant tumors from the benign ones. CONCLUSION: Cytological samples were taken from 100 cases of intracranial tumors that were operated in the neurosurgery clinic of Sisli Etfal Hospital, and the paraffin sections prepared from the biopsy materials were examined. The cases with misdiagnosis were usually differentiated from solid-hard tumors, epithelial-grade cystic structures, and medulloblastoma localized in the posterior fossa, medulloblastoma and ependymoma. However, this method has been found to be very convenient in practice due to its ease technically, low cost and equipment savings.

Correlation between the Expression of PD-L1 and Clinicopathological Parameters in Triple Negative Breast Cancer Patients.

OBJECTIVE: Triple-negative breast cancer (TNBC) is a heterogenous group of tumors with no estrogen receptor (ER), progesterone receptor (PR) and Cerb-B2/HER2 expression. Programmed death ligand-1 (PD-L1) is a transmembrane protein located on both non-tumor and tumor cells and it has been shown to be associated with the escape of tumor cells from the immune system. PD-L1-targeted therapy alone or in combination is now an alternative strategy in several aggressive tumor types. In this respect, TNBC is a potential candidate having limited treatment options and poor outcome. MATERIAL AND METHODS: Sixty-one breast cancers with no expression of ER, PR and Cerb-B2/HER2 were chosen to study PD-L1 immunohistochemistry. PD-L1 staining and its correlation with main clinicopathological parameters were evaluated. RESULTS: The percentage of PD-L1 positivity was 37.7% and 47.5% in tumor and tumor microenvironment, respectively. The positivity rate was higher in breast carcinomas with medullary features (83.3%) and metaplastic carcinoma (66.6%) subgroups. PD-L1 expression of tumors was positively correlated with their Ki-67 score and PD-L1 positivity of the tumor microenvironment. No significant relationship was found between the other variables. CONCLUSION: PD-L1 expression rate was remarkable both in the tumor and the tumor microenvironment of TNBCs. Larger cohorts of TNBC are required to further describe their PD-L1 expression characteristics and help standardize PD-L1 immunohistochemistry assays in these tumors.

Male breast cancer: A 10 year retrospective case series in a tertiary care hospital.

Male breast cancer is a rare disease and it differs from breast cancer in women by some characteristics. The incidence of the disease has increased in the last 25 years. The records of male patients who underwent surgery for breast cancer between 2007 and 2017 were retrospectively reviewed in a tertiary care hospital in Istanbul, Turkey. The patients' ages, background, family history, clinical features, histopathological features of the tumour, its stage, the treatment and the survival were investigated. SPSS 15.0 for Windows programme was used for statistical analysis.Survival analysis was performed with Kaplan-Meier method.Determinants were analysed by univariate Cox regression analysis. A total of 15 patients were evaluated in our study. Fourteen patients had invasive ductal carcinoma and one patient had intraductal papillary carcinoma. The median followup period of the patients was 36 months The axillary lymph node metastasis positivity rate (number of metastatic lymph nodes/number of lymph nodes dissected) was statistically significantly higher in patients who died than in patients who survived.In univariate Cox regression analysis, the effects of age, tumour size, estrogen, progesterone, the presence of HER2/neu receptor and axillary metastasis on survival were not determined. We believe that raising awareness on male breast cancer in the community, genetic testing and screening mammography in high-risk patients will be useful in early diagnosis of the disease and improvement of its prognosis.

Management of Craniopharyngioma.

OBJECTIVE: Craniopharyngiomas are one of the most challenging problems for neurosurgeons because of the high recurrence rates due to their localization and associated endocrinological disorders. This study reports the outcomes of surgeries and recurrence rates of 45 craniopharyngioma cases. METHOD: Patients who were diagnosed with craniopharyngioma in the authors' clinic between 1998 and 2016 evaluated retrospectively. RESULTS: A total of 45 patients (25 males and 20 females; age, 3-56 years) who had previously undergone surgery for craniopharyngioma were enrolled and followed up for 12 to 222 months (mean follow-up duration, 73.5 ±â€Š55.2 months). Among these, 25 were children (55.5%) with a mean age of 9.5 ±â€Š4.6 years and 20 were adults (45.5%) with a mean age of 37.2 ±â€Š12.7 years. A total of 39 (86.6%) patients underwent total tumor resection, while 6 (13.4%) underwent subtotal tumor removal. During 12 to 30 months of follow-up, the progression of residual tumor was recorded in 4 patients, 3 of whom underwent surgery and postoperative radiotherapy. Despite the total resection of tumor in their first surgery, 3 patients showed tumor recurrence during 15 to 34 months of the follow-up. CONCLUSION: Our findings suggest that the total resection of craniopharyngiomas, when possible, results in a favorable quality of life, with acceptable mortality and morbidity rates.

Effect of Cetuximab on the Development of Epidural Fibrosis Based on CD105 and Osteopontin Immunohistochemical Staining.

STUDY DESIGN: The effect of cetuximab on the development of epidural fibrosis (EF) was assessed using immunohistochemical methods as well as antibodies for CD105 and osteopontin (OPN). OBJECTIVE: The goal of this study was to assess of EGFR inhibition for the postoperative treatment of fibrosis. SUMMARY OF BACKGROUND DATA: EF is one of most common causes of failed back surgery syndrome, which occurs after laminectomy. Numerous causes and mechanisms have been proposed to explain its development after laminectomy. Many agents have been tested to prevent the development of EF. EGFR, a multi-functional transmembrane glycoprotein, causes cell growth, proliferation, and EF by interacting with epidermal growth factor and TGF-ß1. The inhibition of postoperative fibrosis using cetuximab, an epidermal growth factor receptor blocker, is theoretically possible. However, this has not been tested to date. METHODS: Sixteen Wistar-Albino rats were divided into two groups, namely, control and cetuximab groups. L1-2 laminectomy alone was performed in both groups, and topical cetuximab was applied to the treatment group. After 6 weeks, rats were sacrificed and examined histopathologically and immunohistochemically; EF tissue was also graded. Statistical significance was accepted at P < 0.05. RESULTS: Fibroblast counts and fibrosis density, determined by histopathologic examination, and EF, according to immunohistochemical assessment based on CD105, were found to be higher in the treatment group than in the control group, and this was statistically significant (P < 0.001). Based on OPN staining, the results were consistent with classical methods, and no significant difference was detected among the groups (P = 0.358). CONCLUSION: Our study revealed that cetuximab inhibits the development of EF and that CD105, and not OPN, is a reliable marker for grading EF. In addition, cetuximab did not result in toxic, systemic side effects in surrounding tissues. LEVEL OF EVIDENCE: N/A.

Solitary Extramedullary Plasmacytoma Mimicking Acute Subdural Hematoma.

BACKGROUND: Solitary extramedullary plasmacytoma (SEP) is a plasma cell neoplasm located outside the bone. It is rarely observed in the intracranial area. It is very difficult to diagnose this condition radiologically before surgery. In addition, dural SEP is usually misdiagnosed. CASE DESCRIPTION: We report a case of plasmacytoma that presented as altered mental status after head trauma, located in the subdural area. We also describe its differential diagnosis and treatment by total removal and adjuvant radiotherapy. The 66-month follow-up findings showed distant plasmacytoma development, which was treated with radiotherapy alone. CONCLUSIONS: Some pathological entities should be considered in the differential diagnosis of acute subdural hematomas. Furthermore, to the best of our knowledge, we report the first case of dural SEP mimicking acute subdural hematoma.

Impact of sorafenib on epidural fibrosis: An immunohistochemical study.

AIM: To determine if sorafenib, an antineoplastic agent, could prevent the development of spinal epidural fibrosis (EF). METHODS: The study used CD105 and osteopontin antibodies in an immunohistochemical approach to quantify EF that occurred as a consequence of laminectomy in rats. Wistar albino rats (n = 16) were divided into two groups: control (L1-2 level laminectomy only) and sorafenib treatment (L1-2 level laminectomy + topical sorafenib). The animals were euthanatized after 6 wk, and the EF tissues were examined for histopathological changes after immunohistochemical staining. The EF grades were assigned to the tissues, and the treatment and control groups were compared. RESULTS: The EF thickness, inflammatory cell density, and arachnoid adherences determined by light microscopy were significantly higher in the control group compared to the sorafenib-treated group. Based on fibrosis scores, the extent of EF in the treatment group was significantly lower than in the controls. Immunohistochemical staining for CD105 to identify microvessels revealed that the EF grades based on vessel count were significantly lower in the treatment group. Staining for osteopontin did not show any significant differences between the groups in terms of the extent of EF. The staging of EF based on vascular counts observed after immunohistochemical staining for CD105, but not for osteopontin, was compatible with conventional staging methods. Neither toxic effects on tissues nor systemic side effects were observed with the use of sorafenib. CONCLUSION: Local administration of sorafenib significantly reduced post-laminectomy EF. Decreased neovascularization in spinal tissue may be due to the sorafenib-induced inhibition of vascular endothelial growth factor.

Filiform Polyposis in Ulcerative Colitis: A Rare Pediatric Case

Background: Filiform polyposis is a rare benign condition referred to as inflammatory polyposis, or pseudopolyposis that is usually found in association with Crohn's disease, ulcerative colitis or granulomatous colitis which is formed by non-specific mucosal and submucosal reactions to previous severe inflammation. It is characterized by multiple finger-like projections most commonly in the transverse and descending colon. Case Report: A 15-year-old girl with a history of ulcerative colitis was admitted to the pediatric emergency department with abdominal pain attacks for the past 2 weeks. Abdominal ultrasound and magnetic resonance enterography revealed mucosal thickening in the transverse and descending colon. Colonoscopy revealed small filiform polyps throughout the colon. Histopathological examination revealed inflammatory polyps associated with ulcerative colitis. Conclusion: Non-neoplastic filiform polyps can be detected even in children with ulcerative colitis with long-term remissions.

A Rare Tumor in Childhood Desmoplastic Infantile Astrocytoma: Two Case Reports.

Desmoplastic infantile astrocytomas (DIAs), are rare supratentorial tumors, usually observed in the first 24 months of life. Despite their aggressive appearance, they tend to follow a favorable clinical course. Total or near total resection of tumor is usually the treatment option. Desmoplastic Infantile Ganglioglioma (DIG) and DIA are WHO grade I tumors that have similar clinical and morphological findings. The only criterion in differential diagnosis is the neural component of DIG. These tumors both have dense fibroblastic stroma and positive staining with glial fibrillar acidic protein (GFAP) and CD34. A rare case of desmoplastic infantile astrocytoma presenting with right side partial seizures presented in a 1-year-old child. A rare case of desmoplastic infantile astrocytoma presenting with focal onset generalized seizures presented in a 1-year-old child. Despite their radiological and histological properties, these tumors have a benign course. After 3-year follow-up for the first case and 1-year follow-up for the second case, there was no recurrence.

Computerized Tomography-Guided Stereotactic Biopsy of Intracranial Lesions: Report of 500 Consecutive Cases.

AIM: Computed tomography (CT)-guided stereotactic brain biopsy has been performed in our clinic since March 1998. In this prospective study, we examined the patient data undergoing stereotactic biopsy and the results of biopsies in 500 consecutive patients. MATERIAL AND METHODS: Between the dates of March 1998 and January 2015, CT-guided stereotactic biopsies were performed by using the Leksell stereotactic frame system (Elekta Instruments EU, Sweden) in 500 patients. A total of 512 procedures were performed in patients consisting of 184 females (36.8%) and 316 males (63.2%), ages ranging from 3 to 81 years (mean 50.40±16.67). RESULTS: Conclusive histopathological diagnosis was not achieved in 17(3.3%) of 512 procedures. Of the others, 173 (33.8%) were high-grade gliomas, 103 (20.1%) were low-grade gliomas, 36 (7%) were malignant lymphomas, 34 (6.6%) were other types of brain tumors, 82 (16%) were metastasis and 67 (13.1%) were non-tumoral lesions. Complications were occurred in ten cases: 3 tumoral bleedings, 2 hypertensive cerebral hematomas, 2 peroperative convulsions, 1 epidural hematoma, 1 myocardial infarction and 1 brain edema. The patients who developed myocardial infarction and hypertensive thalamic hematoma died. The mortality was 0.4% and morbidity was 1.6% in 512 procedures. CONCLUSION: CT-guided stereotactic biopsy is a reliable and a safe procedure in cases with intracranial lesions when histopathological diagnosis is required for the appropriate treatment.

Diagnostic imaging findings of pelvic retroperitoneal ganglioneuroma in a child: a case report with the emphasis on initial ultrasound findings.

Ganglioneuromas are rare benign tumors of neural crest origin developed along the sympathetic chain. The pelvic retroperitoneum is the rarest location of these tumors. Clinically these tumors are commonly asypmtomatic even if they reach large sizes. Here we report the radiological features of a 16 year old boy with pathologically proven retroperitoneal ganglioneuroma that was detected initially by ultrasound. Relevant literature is also discussed.

Antioxidant Effects of Probiotics in Experimentally Induced Peritonitis.

AIM: An experimental study was performed to evaluate the protective effects of probiotics on gut mucosa in peritonitis through antioxidant mechanisms. METHODS: Thirty-two male Wistar albino rats were divided equally into four groups. The rats in Group 1 (control group) underwent laparotomy only. In group 2 (peritonitis group), peritonitis was induced in the rats by the cecal ligation and puncture (CLP) model. In group 3, the rats were treated with probiotics for five days after CLP-induced peritonitis. The last group of rats (group 4) were fed probiotics for five days before the CLP procedure and five days after the surgery. On the fifth day after surgery, all rats were killed, and tissue samples from the terminal ileum were obtained to evaluate the activities of myeloperoxidase (MPO), malondialdehyde (MDA), and glutathione (GSH). Histopathologic examinations were also performed to evaluate the grade of intestinal injury. RESULTS: Myeloperoxidase and MDA activities were increased, GSH concentrations were decreased in group 2, compared with group 1. Intestinal MPO activities in group 4 were decreased compared with group 1 and group 2, indicating a reduction in oxidant activity. Malondialdehyde decreased in group 3 and decreased even more in group 4, compared with the peritonitis group (group 2). Glutathione concentrations were increased in group 4 compared with group 2 and group 3 (p < 0.05). The Chiu scores of the probiotics groups, groups 3 and 4, were lower than those in group 2, indicating reduced mucosal damage in the probiotically fed groups. CONCLUSION: Probiotics have protective effects in peritonitis, which may be related to antioxidant mechanisms. This antioxidant effect of probiotics might occur when pre-conditioning with probiotics before peritonitis because there is sufficient time to prepare the tissues for oxidative damage.

Expression of voltage gated potassium channel ether à go-go in pituitary adenomas of patients with acromegaly: A preliminary study.

OBJECTIVE: To determine immunohistochemical expression of Eag1 in pituitary adenomas of patients with acromegaly and to assess the correlation between Eag1 expression with cavernous sinus invasion, tumoral Ki-67 labeling index (LI), age and gender of the patients. METHODS: The paraffin embedded pituitary adenoma tissue sections of 28 patients with acromegaly who were diagnosed as monohormonal growth hormone (GH) secreting adenomas were immunostained for Eag1 using the avidin-biotin-peroxidase complex method. Eag1 immunoreactivity was scored according to the extensity of the cytoplasm and cell membrane immunoreactivity for Eag1 (score 1 = <10%, score 2 = 10-25%, score 3 = 25-50% and score 4 = >50% of the adenoma cells showed immunoreactivity for Eag1, respectively). RESULTS: Overall, GH secreting pituitary adenomas displayed diverse levels of Eag1 immunoreactivity, however, 64% of the adenomas displayed a strong Eag1 immunoreactivity (score 3 and 4). Five of the tumors displayed Eag1 immunoreactivity score 1, 5 displayed score 2, 10 displayed score 3 and 8 displayed score 4, respectively. No correlation was found between Eag1 immunoreactivity with cavernous sinus invasion, Ki-67 LI, age and gender of the patients. CONCLUSIONS: Our results suggest Eag1 is strongly expressed in the majority of GH secreting pituitary adenomas. However, we could not find any correlation between immunoreactivity of Eag1 with cavernous sinus invasion, Ki-67 LI, age and gender of the patients. Further studies with larger sample sizes are required to demonstrate the role of Eag1 on tumorigenesis, angiogenesis, invasion and response to the treatment in GH secreting pituitary adenomas.