Researcher:
Aslan, Fatih

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Fatih

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Aslan

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Aslan, Fatih

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2018 - 201962020 - 20217

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    Role of endoscopic interventions and electroincision in benign anastomotic strictures following colorectal surgery
    (Aves, 2019) Acar, T.; Acar, N.; Kamer, E.; Unsal, B.; Haciyanli, M.; Aslan, Fatih; Faculty Member; School of Medicine; 219202
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    Clinicopathologic and immunohistochemical characteristics of upper gastrointestinal leiomyomas harboring interstitial cells of Cajal: a potential mimicker of gastrointestinal stromal tumor
    (Elsevier Science inc, 2020) Taşkın, Orhun Çığ; Armutlu, Ayşe; Adsay, Nazmi Volkan; Aslan, Fatih; Kapran, Yersu; Faculty Member; Teaching Faculty; Faculty Member; Faculty Member; Faculty Member; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; Koç University Hospital; 166686; 133567; 286248; 219202; 168101
    Objective: To analyze clinicopathologic characteristics of upper gastrointestinal leiomyomas and to determine the distribution and immunohistochemical features of interstitial cells of Cajal, in order to designate whether they can cause diagnostic challenges. Materials and Methods: Twenty-four upper gastrointestinal leiomyomas (14 esophagus, 10 stomach) were retrieved. CD117, DOG-1 and muscle markers were performed. the staining was analyzed based on the distribution and percentage. interstitial cells of Cajal were distinguished based on their positivity for both CD117 and DOG-1 immunohistochemistry, Along with their morphological features. Results: Mean age of patients was 49 years, M/F ratio was 2.4. Patients with gastric leiomyomas were significantly younger than those with esophageal leiomyomas (41.5 vs. 54.3, p = 0.012). Histologically, leiomyomas were similar to their endometrial counterpart. Immunohistochemically, All tumors had strong/diffuse positivity for muscle markers. CD117 highlighted mast cells in all cases. Three cases had prominently increased mast cells. Both CD117 and DOG-1 also highlighted interstitial cells of Cajal in 24/24 (100%) of cases. interstitial cells of Cajal were distributed in variable proportions, from focal to homogenous. in one case, they constituted 50% of tumor cells. in 16 cases, the distribution was homogenous. Superficial leiomyomas (n = 3) had only focal CD117 and DOG-1 positivity. Conclusion: Upper gastrointestinal leiomyomas harbor expression of CD117 and DOG-1 in entrapped/colonized interstitial cells of Cajal, which can cause a potential pitfall in the differential diagnosis, especially in cases that show prominent immunohistochemical positivity. Evaluation of the immunohistochemistry can be exceptionally challenging in small biopsy/cytology specimens. Careful histologic evaluation of the tumor as well as the recognition of interstitial cells of Cajal will help the pathologist render the accurate diagnosis.
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    Challenges in anesthesia management for peroral endoscopic myotomy: a retrospective analysis
    (Lippincott Williams & Wilkins, 2021) Yurtlu, Derya A.; Aslan, Fatih; Faculty Member; School of Medicine; 219202
    Background: Peroral endoscopic myotomy (POEM) is used to treat achalasia with efficacy and reliability. However, during the procedure potential complications require attention in terms of anesthesia. This study aimed to investigate complications of the POEM procedure and its effects on arterial blood gas (ABG) parameters, peak airway pressures (PIP), hemodynamics, and postoperative analgesia requirements. Methods: Data from 220 patients who underwent POEM between 2014 and 2017 were retrospectively assessed. During the procedure, ABG samples, PIP, mean arterial pressure, and heart rate were recorded. The effects of the procedure and paracentesis on ABG, PIP, mean arterial pressure, heart rate, perioperative complications, and postoperative analgesia requirements were assessed. Results: Data from 220 POEM patients were analyzed. During the procedure, the mean PaCO2 was 48.27 +/- 6.34 mm Hg, which was significantly higher than the PaCO2 values before and after the procedure. The mean increase in maximum PIP was 5.90 +/- 3.49 cmH(2)O during the procedure. However, there was a significant decrease in PaCO2 and PIP values in cases with paracentesis compared with those without paracentesis. With regards to complications, subcutaneous emphysema (48, 21.8%), pneumoperitoneum requiring decompression (66, 30%), pneumothorax (1, 0.5%), aspiration pneumonia (1, 0.5%), and bronchospasm (5, 2.2%) were observed during the procedure. In the postoperative period, 58 patients (26%) had additional analgesia requirements because of visual analog scale values >3. Conclusion: Periprocedural abdominal decompression with veress needle led to a reduction in arterial PaCO2 and PIP, and improved postoperative analgesia. Serious complications because of perioperative aspiration and CO2 insufflation were observed during the POEM procedure.
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    Effect of pegylated interferon and ribavirin on metabolic factors and triglyceride index in chronic hepatitis C patients
    (İzmir Tepecik Eğitim ve Araştırma Hastanesi, 2018) Koyuncu, Betül; Altın, Zeynep; Özer, Serhat; Ünsal, Belkıs; N/A; Aslan, Fatih; Faculty Member; School of Medicine; 219202
    The study aimed to investigate the influence of ribavirin and pegylated interferon alfa 2a/2b combination therapy on metabolic factors and triglyceride index in chronic hepatitis C patients. Method: A total of 165 chronic hepatitis C patients aged between 20 and 75 years with available uric acid and HCV-RNA levels examined at 0, 12, 24., 48., and 72. weeks and admitted to Gastroenterology Department of Atatürk Training and Research Hospital, Katip Çelebi University between January 2005 and January 2012 were enrolled. Patients were divided into groups based on therapy response (sustained viralresponse, relapse, and nonresponders) and the levels of the parameters were evaluated. Results: All patients enrolled in our study were included in our investigation. SVR was achieved in 91 of 165 patients. HCV-RNA levels in patients without sustained viral response were higher than those without. In univariate analyzes, a significant relationship was found between age, 72 hour- HOMA score, platelet counts and log 10 HCV-RNA in patients with and without sustained viral response.In univariate analyzes a significant difference could not found between HOMA scors, and TyG levels. In mutivariate analyzes a significant difference was not found between HOMA scores, and TyG index values, and their impact on treatment was not observed. Conclusion: There is a significant correlation between HOMA score and TyG index in patients with hepatitis C according to our study results. Any correlation could not be found between the TyG index levels and the treatment response. There is a need for prospective studies investigat- ing the reliability of the TyG index in hepatitis C patients. / Öz: Kronik hepatit C olgularının tedavisinde kullanılmakta olan pegile interferon alfa (PEGIFN-a) 2a/2b ve ribavirin tedavisinin trigliserit indeks ve metabolik faktörler üzerine etkisinin incelenmesi amaçlandı. Yöntem: Çalışmaya 01.01.2005 ile 01.11.2012 tarihleri arasında Katip Çelebi Üniversitesi Tıp Fakültesi Atatürk Eğitim Araştırma Hastanesi Gastroenteroloji Polikliniğinde kronik hepatit C tanısı alan, tedavi öncesi ve tedavi sırasında serum ürik asit ve HCV-RNA (0., 12., 24., 48. ve 72. hafta) düzeyleri bakılan, yaşları 20 ile 75 arasında değişen toplam 165 hasta dahil edilmiştir. Tedavi yanıtına göre (kalıcı viral yanıt, relaps ve non-responder-yanıtsız) bu parametrelerin düzeyleri değerlendirilmiştir. Bulgular: Çalışmamıza alınan 165 hastanın tamamı çalışmaya dahil edildi. Dahil edilen 165 hastanın 91’inde kalıcı viral yanıt (SVR) alındı, 74’ünde ise kalıcı viral yanıt alınamadı (non SVR). Kalıcı viral yanıt alınmayan hastaların HCV-RNA düzeyleri kalıcı viral yanıt alınan has- talara göre yüksekti. Tek değişkenli analizlerde kalıcı viral yanıt alınan ve alınmayan hastalarla yaş, 72.saat HOMA skoru, trombosit ve log 10 HCV-RNA arasında anlamlı bir ilişki saptandı. Kalıcı viral yanıt alınan hastalar ile alınmayan hastalar arasında tek değişkenli verilerde hem HOMA skoru hem de TyG indeks değerleri arasında anlamlı fark saptanmadı. Çok değişkenli analiz uygulandığında da hem HOMA skoru hem de TyG indeks değerleri arasında anlamlı fark saptanmadı ve tedaviye etkisinin olmadığı gözlendi. Sonuç: Çalışmamıza göre hepatit C hastalarında HOMA skoruyla TyG indeksi arasında anlamlı korelasyon mevcuttur. TyG indeks düzeyleriyle tedaviye yanıt arasında ise ilişki bulunmamıştır. TyG indeksinin hepatit C hastalarında güvenilirliğini araştıran prospektif çalışmalara gereksi- nim vardır.
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    A new technique in treatment of Zenker diverticulum: submucosal tunneling endoscopic septum division (Z-POEM) versus classic endoscopic septomyotomy techniques
    (Mosby-Elsevier, 2019) N/A; Aslan, Fatih; Yılmaz, Onur; Şengün, Berke; Ünlükaplan, Aytekin; Karahan, Salih Nafiz; Koçak, Elif; Faculty Member; Undergraduate Student; Undergraduate Student; Doctor; Researcher; Undergraduate Student; School of Medicine; School of Medicine; School of Medicine; N/A; School of Medicine; School of Medicine; Koç University Hospital; 219202; N/A; 309087; N/A; 337050; N/A
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    Per-oral endoscopic myotomy (poem) in the treatment of achalasia; clinical outcomes of 430 patients, single center study
    (Mosby-Elsevier, 2019) N/A; Aslan, Fatih; Karahan, Salih Nafiz; Yılmaz, Onur; Şengün, Berke; Koçak, Elif; Darçın, Kamil; Faculty Member; Researcher; Undergraduate Student; Undergraduate Student; Undergraduate Student; Teaching Faculty; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; 219202; 337050; N/A; 309087; N/A; 203217
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    Pathologic evaluation of large colorectal endoscopic submucosal dissections: an analysis of 279 cases with emphasis on the importance of multidisciplinary work and establishing examination protocols
    (Sage Publications Inc, 2020) Yılmaz, Serpil; Taşkın, Orhun Çığ; Aslan, Fatih; Kulaç, İbrahim; Adsay, Nazmi Volkan; Kapran, Yersu; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Faculty Member; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; Koç University Hospital; 166686; 219202; 170305; 286248; 168101
    Background: Endoscopic submucosal dissections (ESDs) allow removal of large gastrointestinal tumors and help patients avoid major oncologic surgery. In this study, the challenges and development of approaches toward successfully handling ESDs were analyzed in 279 colorectal specimens (114 rectal, 47 left, 118 right colonic; 90% adenoma with/without carcinoma). Methods: Each specimen was processed according to an established protocol including gross photography, mapping, and total submission for histopathologic examination. Results: Mean lesion size was 4.2 cm (range: 0.5-22 cm; 28% >= 5 cm; 6% >= 10 cm). Invasive carcinoma was present in 38 cases (14%), which had a mean overall tumor size of 3.8 cm (range: 1.1-17.5 cm), and mean largest size of the invasive component was 0.93 cm (range: 0.04-3 cm). Fifteen cases were staged as pT1a (submucosal invasion of <1000 mu m) and 13 cases as pT1b (submucosal invasion of >= 1000 mu m). En-bloc and R0 resection rates were 99.3% and 90.6%, respectively. Conclusion: Various histopathologic challenges were encountered, which were carefully evaluated by dedicated pathologists with familiarity to the subtleties in handling and reporting these specimens. We recommend these specimens to be prepared in the endoscopy suite, submitted to the Pathology Department oriented, pinned, and placed into copious amount of fixative. Total sampling, gross photography, mapping, and proper fixation are crucial components in the histopathologic evaluation. Micromeasurement of invasion depth and substaging per European/Japanese guidelines as well as accurate measurement of the distance from the resection margins are highly recommended. In conclusion, ESD is an adequate method that can be successfully implemented in a tertiary care center to perform en-bloc and margin-free resections of clinically selected large colorectal superficial lesions.
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    Pathologic evaluation of endoscopically resected non-ampullary duodenal lesions: a single center experience
    (Buluş Design, 2020) Taşkın, Orhun Çığ; Meriçöz, Çisel Aydın; Aslan, Fatih; Adsay, Nazmi Volkan; Kapran, Yersu; Faculty Member; Faculty Member; Koç University Hospital; N/A; N/A; N/A; 286248; 168101
    Objective: endoscopic resections are increasingly being used for superficial gastrointestinal lesions. However, application of these techniques in the duodenum remains challenging, due to the technical difficulties and high complication rates. This study projects a western tertiary center's experience in the endoscopic treatment and diagnostic workup of 19 cases of non-ampullary duodenal lesions. Material and method: specimens (12 endoscopic mucosal resections, 6 endoscopic submucosal dissections, and one endoscopic full-thickness resection) were processed following a strict protocol (photographed, mapped digitally and submitted totally) for histopathologic examination. Clinicopathologic characteristics, margin status and follow-up information were analyzed. Results: the mean age of the 16 patients was 52 years (range: 22-81). Mean lesion size was 1.4 cm (range: 0.3-3.6 cm) for all cases, 2 cm for endoscopic submucosal dissections and 1.1 cm for endoscopic mucosal resections. Mean number of blocks submitted was 4/case. Seven neuroendocrine tumors, 3 tubulovillous adenomas were diagnosed along with nine benign lesions. For endoscopic submucosal dissections, en-bloc and R0 resection rates were 100% (n=6/6) and 83% (n=5/6); for endoscopic mucosal resections, they were 92% (n=11/12) and 83% (n=10/12), respectively. Only one patient had procedure-related late perforation that was managed endoscopically. No mortality was encountered. Conclusion: duodenal endoscopic resections proved successful, safe and feasible methods in a tertiary center. The pathologist's role is to designate the accurate diagnosis, related histopathologic parameters and margin status. The gross protocol was found to be essential in evaluating specimen margins and orientation, as well as in size measurement. We recommend following a standardized approach including gross photography and digital mapping when handling these specimens, for both diagnostic and data collection purposes.
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    Giant IgG4-related pseudotumor of the esophagus resected with endoscopic submucosal dissection: a case report and review of the literature
    (Buluş Design, 2021) Ekinci, Neşe; Kocabey, Duygu Ünal; Gün, Eylül; Aslan, Fatih; Faculty Member; School of Medicine; Koç University Hospital; 219202
    IgG4-related disease (IgG4-RD) is a systemic autoimmune disorder that has been defined in various organs. The disease is characterized by typical clinicopathological features including a dense lymphoplasmacytic infiltrate rich in IgG4 positive plasma cells, storiform fibrosis, obliterative phlebitis, and often an elevated serum IgG4 level. Esophageal IgG4-RD is rare, and its presentation as a solid mass is even more rare. Only 15 previous cases of IgG4-related esophageal disease have been described. We herein present a case of giant IgG4-related pseudotumor of the esophagus resected with endoscopic submucosal dissection (ESD) and a review of the literature. The patient was a 67-year-old man who was admitted to our hospital for assessment of progressive dysphagia. Upper gastrointestinal endoscopy revealed a 9 cm mass in the cervical esophagus. In the previous two hospitals, the patient's mass could not be diagnosed despite repeated biopsies. Because of concerns regarding malignancy, endoscopic submucosal dissection was performed. Histopathological examination showed dense lymphoplasmacytic infiltration with predominant IgG4-positive plasma cells on a sclerotic background. The patient was diagnosed with IgG4-RD. During the follow-up, no residual mass was detected but the patient was diagnosed with lung adenocarcinoma. We present a unique case of giant IgG4-related pseudotumor of the esophagus. Resection with ESD of such a big mass of IgG4-RD in the esophageal region has never been reported before in the literature.
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    Endoscopic submucosal dissection of seborrheic keratosis-like lesion of the esophagus: a new entity?
    (Federation of Turkish Pathology Societies, 2020) Ekinci, Neşe; Gün, Eylül; Aslan, Fatih; Faculty Member; Koç University Hospital; 219202
    Seborrheic keratosis, one of the most common lesions of the epidermis, is rarely seen on mucosal surfaces. We report a case of a distinctive epithelial neoplasm of the esophagus showing close resemblance to seborrheic keratosis that was resected with endoscopic submucosal dissection. A 65-year-old patient's previous esophageal biopsy showed suspicious low grade dysplasia and the patient was referred for endoscopic submucosal dissection of a flat lesion in the mid-esophagus. Macroscopic examination revealed a well circumscribed, pigmented and elevated lesion with a diameter of 20 mm. Microscopically, the lesion was well circumscribed, with plaque-like elevation, and showed hyperkeratosis, acanthosis, and papillomatosis. Broad coalescing solid sheets and interconnecting trabeculae of basaloid cells were the consistent feature throughout the lesion. Squamous eddies and occasional central keratinization were present. Mitotic activity and koilocytes were not identified. Immunohistochemically, the lesion showed diffuse nuclear positivity with p63 and negativity with p16. Ki-67 index was confined to the basal cell layer. With the help of histopathologic and immunohistochemical findings, we diagnosed this morphologically benign case as "seborrheic keratosis-like lesion of the esophagus". It should be kept in mind that seborrheic keratosis-like lesions might be rarely seen on mucosal surfaces such as the esophagus. Endoscopic submucosal dissection is a new, curative, and safe endoscopic resection technique in en-bloc resection of superficial esophageal lesions. To our knowledge, this is the first case of the aforementioned lesion in the esophagus being resected with endoscopic submucosal dissection.