Arbil Acikalin

Aim: Gastrointestinal stromal tumors (GISTs) exhibit marked heterogeneous clinical behavior that is not fully captured by conventional risk classification systems. This study aimed to evaluate the prognostic significance of loss of p16 expression and EZH2 overexpression and their relationship with clinicopathological parameters in GIST.Methods: In this retrospective study, 113 GIST cases diagnosed at a single institution between 2016 and 2026 were evaluated. Expression of p16 and EZH2 was evaluated immunohistochemically and correlated with clinicopathological parameters and overall survival using Kaplan-Meier and Cox regression analyses.Results: p16 loss was detected in 34 cases (30.1%) and EZH2 overexpression in 12 cases (10.6%). Both markers were significantly correlated with high mitotic activity, tumor necrosis, metastasis, multifocality, a high AFIP risk category, and elevated Ki-67 proliferation index (p

Purpose: The aim of this study was to compare the clinicopathological features, while evaluating the frequency of MSI, and the survival rates in these patients in our patient group with MSI and microsatellite stabil (MSS) colorectal carcinomas (CRCs). Materials and Methods: We retrospectively enrolled 146 patients who underwent colon resection between the years of 2014-2022. The expression of MSI status was evaluated by immunohistochemistry. The association of MSI status, presense of tumor-infiltrating lymphocytes (TILs), and tumor budding score with a patient’s survival was assessed by the Kaplan–Meier method and Cox regression analysis. Results: There were 104 (71.2%) MSS cases and, 42 (28.8%) MSI cases. 15 (10.3%) MSI tumors were found to be MSI-low, and 27 (18.5%) to be MSI-high. MSI tumors were significantly associated with younger patients (<50), earlier stage (T1-T2), right localization, lower rate of lymph node metastasis, presence of mucinous component and TILs response. The Cox-regression model revealed TILs, tumor budding score, and MSI are variables that significantly affect survival. The presence of TILs exhibited a protective effect (Hazard ratio (HR)=0.446), which decreased the mortality risk by 2.24 times for the follow-up period, while the presence of high TBS increased the risk of mortality by HR=3.22. Conclusion: This study revealed that patients with MSI CRCs may show unique clinicopathological features and should be evaluated using some guiding parameters that will improve survival.

Introduction: Paragangliomas are tumors of neuroendocrine origin, may appear in different localizations, and are related to the autonomic nervous system. Paragangliomas are generally asymptomatic and may rarely appear with adrenergic symptoms, and clinical findings depend on the catecholamines they secrete. Extra-adrenal paragangliomas are mostly benign, like all paragangliomas. Malignancy criteria consist of local recurrence, metastasis after total resection, and presence of distant metastasis during primary diagnosis. Case Presentation: This report presents the case of a 31-year-old man with jugular paraganglioma, multiple skeletal metastases, and a long-segment tumor thrombus. Imaging procedures showed a continuous tumor thrombus extending from the posterior fossa to the right atrium and metastases in C2, T1, T6, T8, L5, and right humerus. Histopathological assessment of the metastasis in C2 identified malignant paraganglioma. Curative surgery was not an option for this patient, hence combined chemotherapy was given. Conclusion: In cases of malignant paraganglioma with multiple distant metastases, chemotherapy and radiotherapy are feasible treatment methods.

To present the demographic, etiological, clinical, and mycological characteristics and treatment results of fungal keratitis patients admitted to our clinic. The medical records of patients diagnosed with fungal keratitis between October 2012 and 2018 were reviewed. The diagnosis of fungal keratitis was confirmed mycologically and/or cytologically. Treatment response was defined as complete infiltrate resolution and re-epithelization with medical treatment and minor surgical interventions. Patients who underwent penetrating keratoplasty or evisceration due to clinical deterioration despite treatment were classified as treatment nonresponders and were compared with responders in terms of demographic, etiological, and clinical characteristics. Seventy-two (12.8%) of 559 patients diagnosed with microbial keratitis in the 6-year period were fungal keratitis. Of these, 38 cases (38 eyes) without polymicrobial etiology were included in the study. The patients’ mean age was 44.9±19.0 years (range: 2-80) and males predominated (14 females [36.8%], 24 males [63.2%]). Trauma (63.6%) was the most common predisposing factor in patients younger than 40 years old, whereas pathologies impairing ocular surface immunity were the leading risk factor (48.1%) in patients older than 40 years. Filamentous fungi were detected in 34 (89.5%) cases, while yeasts were found in 4 (10.5%) cases. Among 26 cases with positive cultures, Aspergillus species were the most common pathogens (42.3%). Infiltrate size before treatment was larger in nonresponders (14/38, 36.8%) compared to treatment responders (19/38, 50%) (p=0.049). In addition, rates of treatment response were higher in cases in which the infiltrate was located paracentrally compared to other cases (p=0.036). Fungal keratitis is an important public health problem in our region. Ocular trauma is a leading etiology in men under the age of 40 years. In the 6-year period, we observed that the main causes of fungal keratitis were filamentous fungi, and most commonly Aspergillus species. In cases presenting with large and central lesions, aggressive treatment options should be considered and these patients should be followed up more closely.

Introduction: Extraneural metastases of glioblastoma are very rare clinical entities, especially in pediatric patients. Because of their rarity, they can be confused with other pathological processes. Case Presentation: We report a case of 16-year-old boy with extensive extraneural metastases of glioblastoma. Lung, liver, cervical lymph nodes, skin, and bone metastases were detected in the patient. Conclusion: We describe the presentation, evaluation, and diagnosis of this rare condition with regard to pertinent literature.

Background: Silent pituitary adenomas are clinically found to be non-functional (i.e., without clinically evident pituitary hormone production). Introduction: The aim of this study was to investigate subjects with silent pituitary adenomas for possible variations in their clinical status. Methods: A total of 102 patients who had undergone surgery for pituitary adenoma and had been diagnosed with silent pituitary adenoma was included in the study. The patients’ preoperative and postoperative hormonal parameters and magnetic resonance imaging (MRI) features were collected, and pathological specimens were re-evaluated. Results: Immunohistochemistry results of the 102 patients were as follows: hormone-negative adenomas (n=35) 35.5%; FSH+LH-positivity (n=32) 31.3%; ACTH-positivity (n=11) 10.7%; α-subunit-positivity (n= 9) 8.8%; prolactin-positivity (n=8) 7.8%; GH-positivity (n=6) 5.4%; and plurihormonal adenoma (n=1). The mean sizes of SGA, SGHA, and SCA were 28.0±12.7, 30.0±16.0, and 27.7±8.9mm (p>0.05), respectively. With the exception of silent gonadotroph adenomas (SGAs), female gender dominance was shown in patients with silent growth hormone adenoma (SGHA) and silent corticotroph adenoma (SCA). Although no clinical relevance was observed in relation to hormonal excess, preoperative GH (4.21±4.6,vs 0.27±0.36 p=0.00) was slightly more elevated in SGHA than in GH-negative adenomas. Additionally, preoperative basal ACTH values (47.3±28.7 vs 23.9±14.4, p=0.003) were also higher in SCA compared to the other types. Our findings revealed SCAs to be more aggressive behaviour than SGHAs and SGAs due to invasiveness in radiological imaging, their elevated re-operation and postoperative ACTH values. Conclusion: Silent pituitary adenomas represent a challenging diagnostic tumour group. Careful initial evaluation of patients with pituitary adenomas should consider any mild signs and symptoms of functionality, particularly in cases of GH- and ACTH-secreting adenomas.

Purpose: The aim of the study was to review our clinical 7 years experiences with silent corticotroph adenoma (SCA) and Cushing disease (CD) with regard to clinical, radiological features, immunohistochemical and surgical outcomes and compare the results between two groups. Material and Methods: We retrospectively reviewed a series of patients (n=17; SCA 10, CD 7) with corticotroph adenomas and collected biochemical, neuroradiological and pathological data of those during follow-up time. Results: Mean pre-operative ACTH values of the patients with CD and SCA were 60.429.5, 45.5 +/- 34.6 pg/mL, respectively. Mean preoperative cortisol of the patient with CD (21.2 +/- 4.4 vs 11.5 +/- 4.0 mcg/dL) was increased than the patients with SCA measurements'. Patients with SCA had larger pituitary mass (20.4 +/- 4.5 vs 8.8 +/- 4.0 mm) than the patients with CD. And cavernous sinus invasion also was determined in all patients with SCA. Sparsely granulation staining was more common in all patients with SCA (7/10) or CD (4/7). Conclusion: SCAs are totally different from functional CD adenomas related with clinical characteristics and postoperative outcomes. SCA can be thought of as a diverse group of pituitary adenomas.

Purpose: The aim of this study was to evaluate patients formerly diagnosed as neurofibroma and schwannoma in terms of hybrid peripheral nerve sheath tumors (PNSTs) via histopathological and immunohistochemical analysis. Materials and Methods: In this retrospective study, 115 patients formerly diagnosed as either neurofibroma or schwannoma were re-evaluated histopathologically. Among these patients, 32 cases which showed mixed morphology, suspicious for hybrid PNST were included in the study. Immunohistochemically, S100, CD34, EMA and ki67 were performed to these 32 cases, suspicious for hybrid PNST.Results: Based on histopathology, 32 of 115 (27.8%) cases were suspicious for hybrid PNST. By the addition of immunohistochemical staining results; 22 of 32 cases were definitely diagnosed as hybrid PNST; of which 18 (81.8%) as schwannoma-neurofibroma and, 4 (18.2%) cases as schwannoma-perineurioma. Conclusion: Hybrid PNSTs are usually benign and have distinct histopathologic and immunohistochemistry findings. In the literature, rare case reports have described local recurrence and malignant transformation in hybrid PNSTs. Therefore, further studies are needed to demonstrate the pathogenetic and prognostic significance of these tumors. Because of the risk of recurrence and malignancy potential, these tumors should be kept in mind in diagnosis of peripheral nerve sheath tumors.

Aim: Lymphomas are the second most common malignant disease after leukemia and brain tumors in developing contries. Ebstein-Barr virus has a initiator role in the development of lymphoma, but it is known that socioeconomic conditions, genetic features and the immune supressive factors is also important. We aimed to explore the histopathologic subtypes of pediatric lymphomas and their relation with Ebstein-Barr virüs infection in our region.Material and Methods: In this retrospective study, 87 children including 36 cases with hodgkin lymphoma and 51 cases with non-hodgkin lymphoma were included in the study. The pathologic slides were used to investigate immunohistochemical staining with Ebstein-Barr virüs latent membrane protein-1 and in-situ hybridization. Results: The most common histopathological subtype in hodgkin lymphoma cases were mixed cellular classical Hodgkin lymphoma (55.6%) followed by nodular sclerosis classical hodgkin lymphoma (16.6%). The most common histopathological subtype in non-Hodgkin lymphoma cases was Burkitt lymphoma (51.0%) followed by precursor T-cell lymphoblastic leukemia/lymphoma (13.7%). Ebstein-Barr virüs latent membrane protein-1 was positive in 29 Hodgkin lymphoma. All non-Hodgkin lymphoma cases were stained negative with ımmunohistochemical. The positive staining rate of Hodgkin lymphoma cases with in-situ hybridization was 83.3% and this rate was 27.5% in non-Hodgkin lymphoma cases. The differences between groups for both staining methods were statistically significant (p<0.001) Conclusion: The results of this study show that the distribution of histopatholojik subtypes of pediatric lymphomas similar to in developing countries. And we have observed that in-situ hybridization is more specific than immunohistochemistry because Ebstein-Barr virus positivity is more detected in in-situ hybridization.