Publications by authors named "Aydin Sav"

Computational neurosurgery is a novel and disruptive field where artificial intelligence and computational modeling are used to improve the diagnosis, treatment, and prognosis of patients affected by diseases of neurosurgical relevance. The field aims to bring new knowledge to clinical neurosciences and inform on the profound questions related to the human brain by applying augmented intelligence, where the power of artificial intelligence and computational inference can enhance human expertise. This transformative field requires the articulation of ethical considerations that will enable scientists, engineers, and clinical neuroscientists, including neurosurgeons, to ensure that the use of such a powerful application is conducted based on the highest moral and ethical standards with a patient-centric approach to predict and prevent mistakes.

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Objective: The authors report on a large, consecutive, single-surgeon series of patients undergoing microsurgical removal of midbrain gliomas. Emphasis is put on surgical indications, technique, and results as well as long-term oncological follow-up.

Methods: A retrospective analysis was performed of prospectively collected data from a consecutive series of patients undergoing microneurosurgery for midbrain gliomas from March 2006 through June 2022 at the authors' institution.

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Erdheim-Chester disease is a non-Langerhans cell histiocytosis syndrome characterised by histiocytic infiltration of different organs and systems in the body. Erdheim-Chester disease with isolated central nervous system (CNS) involvement causes diagnostic difficulties due to the absence of systemic findings and may result in misdiagnosis and inaccurate treatment choices. The case discussed in this report exemplifies how challenging it is to diagnose Erdheim-Chester disease with isolated CNS involvement.

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Tanycytic ependymoma is a neuroectodermal tumor that arises from ependymoglial cells or tanycytes. It is highly uncommon. We reported a 34-year-old man who was diagnosed with intradural-intramedullary tanycytic ependymoma, located at the level of C4-5 who had a 9-months history of neck pain and left arm pain, and numbness on fingers.

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Despite most of the prolactinomas can be treated with endocrine therapy and/or surgery, a significant percentage of these tumors can be resistant to endocrine treatments and/or recur with prominent invasion into the surrounding anatomical structures. Hence, clinical, pathological, and molecular definitions of aggressive prolactinomas are important to guide for classical and novel treatment modalities. In this review, we aimed to define molecular endocrinological features of dopamine agonist-resistant and aggressive prolactinomas for designing future multimodality treatments.

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Background: Dural thickening is observed in lymphoma, dural carcinomatosis, meningioma, tuberculosis, and autoimmune diseases. We encountered a patient with dural thickening and complaints of neck and back pain, numbness and loss of strength in the hands. The patient also suffered from polychondritis and had previously received steroid and methotrexate treatment for this indication.

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Context: The relationship between the endocrine system and autoimmunity has been recognized for a long time and one of the best examples of autoimmune endocrine disease is autoimmune hypophysitis. A better understanding of autoimmune mechanisms and radiological, biochemical, and immunological developments has given rise to the definition of new autoimmune disorders including autoimmunity-related hypothalamic-pituitary disorders. However, whether hypothalamitis may occur as a distinct entity is still a matter of debate.

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Mutations in isocitrate dehydrogenase genes IDH1 and IDH2 are frequently found in diffuse and anaplastic astrocytic and oligodendroglial tumours as well as in secondary glioblastomas. As IDH is a very important prognostic, diagnostic and therapeutic biomarker for glioma, it is of paramount importance to determine its mutational status. The haematoxylin and eosin (H&E) staining is a valuable tool in precision oncology as it guides histopathology-based diagnosis and proceeding patient's treatment.

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Purpose: Traumatic brain injury most commonly affects young adults under the age of 35 and frequently results in reduced quality of life, disability, and death. In long-term survivors, hypopituitarism is a common complication.

Results: Pituitary dysfunction occurs in approximately 20-40% of patients diagnosed with moderate and severe traumatic brain injury giving rise to growth hormone deficiency, hypogonadism, hypothyroidism, hypocortisolism, and central diabetes insipidus.

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Background: Intramedullary glial neoplasms affecting the entire spinal cord from the cervicomedullary junction to conus medullaris are termed holocord tumors. Pilocytic astrocytomas are relatively uncommon tumors forming holocord involvement. Hitherto 24 holocord astrocytoma cases were reported in the literature.

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Background: Meningiomas are heterogeneous, with differences in anatomical, histopathological, and clinical characteristics. Such spatial variability in meningioma biology is thought to result from differences in the expression of critical developmental regulators. We hypothesized that the variability in meningioma biology would follow gradients such as in embryology and tested a cohort of 366 meningiomas for histopathological and immunohistochemical gradients.

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Whorling-Sclerosing variant of meningioma (WSM) is a very rare variant of meningioma and only 28 cases were previously reported in the English medical literature. The term "whorling" describes different morphological features including psammoma bodies formed by precipitated calcium or by layered whorling sheets of tumor cells in meningothelial meningiomas. In WSM, the sclerosing structures are formed by typical paucicellular or acellular collagen whorls which form the majority of tumor volume.

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Precise tiered tumor grading is essential for predicting prognosis, selecting different treatment options and for follow-up of brain tumor patients. Ki67 labeling index (LI) is widely employed in assessing aggressiveness of glial brain tumors. However, Ki67 is subject to interlaboratory variability, and its antigen is expressed on all cell cycle phases except G0, which hinders its usage as a precise criterion for assessing cell proliferation.

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OBJECTIVE Recent studies have established that hemispheric diffuse gliomas may be grouped into subsets on the basis of molecular markers; these subsets are loosely correlated with the histopathological diagnosis but are strong predictors of clinical tumor behavior. Based on an analysis of molecular and clinical parameters, the authors hypothesized that mutations of the telomerase promoter (TERTp-mut) mark separate oncogenic programs among isocitrate dehydrogenase 1 and/or 2 (IDH) mutant (IDH-mut) and IDH wild-type (IDH-wt) diffuse gliomas independent of histopathology or WHO grade. METHODS Four molecular subsets of the combined statuses of IDH and TERT-promoter mutations (double mutant, IDH only, TERT only, and double negative) were defined.

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To date, several cell proliferation markers, apoptosis, vascular markers, oncogenes, tumor suppressor genes, cell cycle mediators, microRNA (miRNAs), and long noncoding RNAs (lncRNAs) have been identified to be involved in the tumorigenesis, migration, proliferation and invasiveness of pituitary adenomas. There are still no reliable morphologic markers predictive of pituitary adenoma recurrence. Recent scientific research introduced new techniques to enable us to attain new information on the genesis and biologic behavior of pituitary adenomas.

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Temozolomide may cause thrombocytopenia or neutropenia in 3-4% of glioblastoma patients, respectively. However, pancytopenia is rarely reported. MGMT (O6-methylguanine-DNA-methyltransferase) enzyme repairs temozolomide-induced DNA mutations and associates both with antitumour efficacy and myelosuppression.

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Spinal nerve root hemangioblastomas present mostly as intradural-extradurally. Purely extradural spinal nerve root hemangioblastoma is a very rare entity. In this study, we aimed to analyze epidemiological perspectives of purely extradural spinal nerve root hemangioblastomas presented in English medical literature in addition to our own exemplary case.

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The single nucleotide polymorphism rs55705857, located in a non-coding but evolutionarily conserved region at 8q24.21, is strongly associated with IDH-mutant glioma development and was suggested to be a causal variant. However, the molecular mechanism underlying this association has remained unknown.

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Background: Meningiomas are one of the most common tumours to affect the central nervous system. Genetic mutations are important in meningeal tumourigenesis, progression and prognosis. In this study, we aimed to examine the effect of 1p/19q deletion on the diagnosis and prognosis of meningioma subtypes using the fluorescence in situ hybridization (FISH) method.

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Pituitary carcinoma is a rare tumor originating from adenohypophyseal cells. Currently, diverse pathogenetic mechanisms, i.e.

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A 32-year-old man presented with gradually increasing bilateral buttock pain. He had intermittent claudication. Multiple, homogenously enhanced intradural extramedullary lesions at L2-L3 and L5-S1 levels were observed on magnetic resonance imaging.

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Introduction: Arachnoid cysts (ACs) are frequently found on intracranial imaging studies but intrasellar arachnoid cysts are rarely encountered.

Presentation Of Case: We present a 49-year old patient who had headaches for 6 months and cystic sellar mass was found in his cranial imaging. We operated him by transnasal transsphenoidal route.

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