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Dive into the research topics where Eren Demirtas is active.

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Featured researches published by Eren Demirtas.


Pediatric Neurosurgery | 1996

Split Cord Malformations: Report of Three Unusual Cases

Yusuf Erşahin; Eren Demirtas; Saffet Mutluer; Ali Riza Tosun; Selçuk Saydam

The unified theory, proposed by Pang et al., explains the embryogenetic mechanisms of all variants of split cord malformations (SCMs). All SCMs originate from one basic error occurring around the time when the primitive neurenteric canal closes. The basic error is the formation of an accessory neurenteric canal between the yolk sac and amnion which is subsequently invested with mesenchyme to form an endomesenchymal tract that splits the notochord and neural plate. Three cases of SCMs which support this unified theory are presented. A 3-month-old girl had a combination of both types of SCMs at the level of T11. The 2nd case, a 2-week-old girl, had type-II SCM associated with a thickened filum terminale, lipomyelomeningocele and ectopic renal tissue within lipoma. A lipomatous tract extending from a subcutaneous lipoma to the intradural fibrous septum contained lymphoid tissues and tubular epithelia in a 3-month-old boy with a type-II SCM. These 3 cases support the unified theory.


Pathology Research and Practice | 2000

Intracranial meningeal tumours in childhood: a clinicopathologic study including MIB-1 immunohistochemistry.

Eren Demirtas; Yusuf Erşahin; Funda Yilmaz; Saffet Mutluer; Ali Veral

Primary tumours of the meninges with a relatively high tendency for malignant behaviour are uncommon in childhood. This study concerns 18 cases of meningeal tumours in children under the age of 16, of which 13 were meningiomas and five were other tumours arising in the meninges. Meningiomas showed a preponderance in females as in adult series, and the majority were supratentorial in localisation. The percentage of meningeal tumours and meningiomas among all brain tumours in our centre were 3.72% and 2.69%, respectively. Four out of 13 meningiomas were fibroblastic, four were transitional, one was meningothelial, two were psammomatous and two were papillary meningiomas. Seven (38.8%) out of 18 tumours showed anaplastic features, including two papillary meningiomas, two hemangiopericytomas, one mesenchymal chondrosarcoma, one pleomorphic sarcoma and one anaplastic meningeal tumour. Papillary meningiomas with hemangiopericytoma-like solid areas were seen frequently in our cases (15.3%). Meningoangiomatosis was associated with two meningeal tumours. MIB1 (Ki-67) labelling indices (LIs) ranged between 0% and 13.6% (mean 1.83%) in benign, and between 1% and 20% (mean 7.2%) in malignant tumour, including papillary meningiomas. Mean MIB-1 LIs were 5.61% and 1.14% in non-recurrent and recurrent cases, respectively. MIB-1 LIs showed significant differences between benign and malignant meningeal tumours but no significant correlation either with prognosis or recurrence. Despite the fact that brain tumours are among the most common neoplasms of childhood, meningeal tumours are rare lesions, accounting for less than 2% of published series of intracranial neoplasms in childhood [5, 8, 18, 24, 30, 32]. It has been suggested that the clinical and pathological characteristics of meningiomas in this age group differ from those of adults [14, 18, 24, 45]. Besides meningiomas, there are a few reports of other meningeal tumours in childhood and difficulties in differential diagnosis may arise within this group, especially in anaplastic tumours [11, 13, 32, 44, 46]. One of the major problems in meningiomas and some tumours arising in the meninges is the discordance that arises between the histologic appearance of the tumour and behaviour [4]. Several studies have attempted to determine the proliferation potential of meningiomas, including immunohistochemical labelling with monoclonal antibodies to Ki-67, proliferating cell nuclear antigen (PCNA), and bromodeoxyuridine (BUdR); flow cytometric DNA analysis; or argyrophilic nucleolar organizer regions (AgNORs) counting [9, 10, 15, 19, 22, 26, 31, 35, 53]. The studies concerning proliferation markers have contradictory results [9, 10, 15, 26, 31, 42, 53]. MIB-1 detects the same or a similar epitope as the original antibody Ki-67 and reacts with a proliferation associated antigen expressed in all active parts of the cell cycle, G1, S, G2 and M (mitosis), but not in the G0 or quiescent phases [7]. In this study we examined the clinicopathological characteristics and MIB1 values of 18 meningeal tumours in children under the age of 16 years within the last 25 years (from 1970 to 1995).


Brain & Development | 2001

Molybdenum cofactor deficiency associated with Dandy–Walker complex

Sertac Arslanoglu; Mehmet Yalaz; Damla Goksen; Mahmut Çoker; Sarenur Tutuncuoglu; Mete Akisu; Sukran Darcan; Nilgun Kultursay; Metin Ciris; Eren Demirtas

Molybdenum cofactor deficiency is a rare and devastating disease leading to intractable seizures in the neonatal period. Severe loss of neocortical neurons, gliosis, and cystic necrosis of cerebral white matter resulting in significant cerebral volume loss are the neuropathological findings. The mechanism of cerebral injury is unknown, but sulphite excess, and sulphate or uric acid deficiencies are possible factors. We present here a new case of Molybdenum cofactor deficiency associated with Dandy-Walker complex with a history of three dead siblings, the latter also having Dandy-Walker malformation. We speculate that severe cerebral volume loss due to the above mentioned mechanisms may lead to an appearance resembling Dandy-Walker malformation.


Clinical Neurology and Neurosurgery | 1995

A cse of Rathke's cleft cyst presenting with diabetes insipidus

Yusuf Erşahin; Nurcan Özdamar; Eren Demirtas; Saffet Mutluer

Rathkes cleft cysts (RCCs) are considered to arise from the remnants of Rathkes pouch, an invagination of the stomodeum. They are classically described as benign epithelium lined intrasellar cysts containing mucoid material, and also found in 2-33% of routine autopsy series. The most common presenting symptoms are visual impairment, hypothalamic dysfunction, hypopituitarism and headache. Diabetes insipidus has been described in patients with RCC. Very few cases presented with only diabetes insipidus in adults. To our knowledge, our patient is the first case of RCC presenting with only diabetes insipidus in childhood. A 9-year-old girl presented with diabetes insipidus. The physical, neurological and endocrinological examinations were normal, except for diabetes insipidus. Magnetic resonance imaging scan revealed a hyperintense lesion with supra sellar extension in the posterior pituitary both on T1 and T2 weighted images. Subtotal excision of RCC was performed via transsphenoidal surgery. However, diabetes insipidus persisted after the surgery.


Acta Neurochirurgica | 1996

Recurrence of meningiomas versus proliferating cell nuclear antigen (PCNA) positivity and AgNOR counting

Eren Demirtas; F. Yilmaz; I. Övül; K. Öner

SummaryMeningiomas have a wide range of biological potential and clinical behaviour. Histological findings are helpful in recognizing the malignant potential but often fail to correlate with clinical behaviour. This study attempts to correlate the silver nucleolar organizer regions (AgNORs) and proliferating cell nuclear antigen (PCNA) with clinicopathological features of biological activity. Thirty-four completely resected meningiomas were classified as benign [19], atypical [6] and malignant [9]. Forty-eight initial and recurrent tumour materials were investigated for staining of AgNORs and immunohistochemistry using monoclonal antibodies against PCNA (clone 19A2 and PC10). There were no differences between the recurrent and non-recurrent cases with regards to AgNOR, PC10 and 19A2 values. Also, no significant difference was found between the primary and recurrent tumours. Both PC10 and 19A2 labelling indices (LI) showed a significant difference between benign and malignant meningiomas. The 19A2 LI was 0.56 ± 0.21 in benign and 2.45 ± 16 in atypical meningiomas. The 19 A2 counts showed significant difference between benign and atypical tumours but PC10 values failed to show such a correlation. AgNOR and PCNA indices were not found to be useful in predicting recurrences compared to the surgical procedure and histopathological criteria.


Clinical Neurology and Neurosurgery | 1995

A case of thalamic hydatid cyst

Yusuf Erşahin; Saffet Mutluer; Eren Demirtas; Taskin Yurtseven

Cerebral hydatidosis account for approximately 1-2% of patients with hydatid disease. Fifty percent to 75% of intracranial hydatid cysts are seen in children. The cerebral hydatid cysts are usually single and located in the watershed of the middle cerebral artery. To our knowledge, no case of hydatid cyst in the thalamic location has been reported. A 4-year-old boy presented with the left sided weakness. A right thalamic hydatid cyst without rim enhancement and perifocal oedema was detected on the computed tomographic (CT) scan. He was put on albendazole, but headache, nausea and vomiting developed and hemiparesis got worse in the following two weeks. The non-contrast repeat CT showed the pericystic oedema. The rim enhancement and pericystic oedema were also present on magnetic resonance imaging scans. The right thalamic hydatid cyst was removed via the transcallosal approach. The cyst aspiration and intracystic injection of hypertonic saline were performed before the cyst removal. Leakage of the cyst fluid was conceivably the cause of the development of rim enhancement and pericystic oedema. Patients receiving albendazole for the treatment of cerebral hydatid cysts should be closely followed. The surgery is still the choice of treatment in cerebral hybrid cysts, in our opinion.


Childs Nervous System | 2000

Intraosseous neurinoma of the parietal bone.

Yusuf Erşahin; Saffet Mutluer; Eren Demirtas

Abstract Intraosseous neurinoma is very uncommon tumor. Its location in the skull is extremely rare. A 4-year-old boy presented with a lump in the right occipital region. Computed tomography revealed a soft tissue mass with bony erosion in the right occipital bone. The solid, nontender, and immobile mass was totally removed. The pathological examination showed that it was an intraosseous neurinoma. Total resection of intraosseous neurinomas is sufficient treatment and is not followed by recurrence.


Childs Nervous System | 1993

Dumbbell ganglioneuromas in childhood

Saffet Mutluer; Yusuf Erşahin; Özcan Binatlı; Eren Demirtas

The incidence of dumbbell tumors among spinal neoplasms is between 10% and 15%. Approximately 1% of neoplasms located at or near the spinal cord are ganglioneuromas. Ganglioneuromas are rare, slow-growing, benign tumors arising from sympathetic ganglia. The cases of two children with spinal dumbbell ganglioneuroma are presented. The tumors were totally resected by combined surgery in both patients. The patients are neurologically intact 5 and 4 years respectively after surgery.


Childs Nervous System | 1999

Meningioma of the cavernous sinus in a child

Yusuf Erşahin; Nurcan Özdamar; Eren Demirtas; Murat Karabiyikoğlu

Abstract Intracranial meningiomas in children are rare, representing 1–4.2% of central nervous system tumors and 1.5–1.8% of all intracranial meningiomas. Meningiomas arising from the lateral wall of the cavernous sinus account for less than 1% of all intracranial meningiomas. To our knowledge, only one case of a meningioma arising from the cavernous sinus has been reported in childhood. A 6-year-old boy presented with left ophthalmoplegia. A slight drooping of the left eyelid was noted at the age of 1 year. Magnetic resonance imaging (MRI) with contrast administration revealed an enhancing mass lesion located in the left cavernous sinus. The tumor, arising from the lateral wall of the cavernous sinus, was totally removed and the oculomotor nerve was reconstructed with a sural nerve graft. MRI displayed total tumor removal 1 month after the surgery. The pathological diagnosis was of a psammomatous meningioma.


Brain & Development | 1997

Infantile polymyositis with normal serum creatine kinase level

Sarenur Tütüncüogˇlu; Hasan Tekgul; Eren Demirtas; Seval Uysal

A 30-month-old boy who has been suffering progressive proximal muscle weakness and severe atrophy in shoulder and hip muscles from 11 months of age had prominent perivascular inflammatory cellular infiltration in his muscle biopsy and myopathic EMG changes. But his serum creatine kinase (CK) levels were repeatedly found to be within normal ranges. Oral prednisolone therapy (2 mg/kg/d) brought a complete recovery of muscle power and normalization of EMG and muscle biopsy findings. This report provides an additional support that the cases of infantile polymyositis with normal serum CK levels may respond well to steroid therapy.

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