Necrotic rhabdoid meningiomas with aggressive clinical behavior.

Rhabdoid meningioma (RM) is a rare, aggressive variant of meningioma classified as a WHO Grade III malignancy. RM exhibits a striking histological resemblance to other rhabdoid tumors and strong tendency towards local recurrences, CSF dissemination, and/or remote metastasis. The majority of reported cases are of secondary rhabdoid transformation in recurrent meningiomas. We present two unusual cases of rhabdoid meningiomas diagnosed as a primary intracranial lesion in adults that were associated with extensive necrosis and an aggressive clinical course. On histological examination, the majority of the tumor mass was composed of necrotic tissue with focal clusters of neoplastic cells, often localized around blood vessels. Most tumor cells exhibited typical rhabdoid morphology with large, vesicular, often eccentrically located nuclei with distinct nucleoli and abundant cytoplasm containing eosinophilic hyaline inclusions. Classical meningothelial features with focal whorl formation were scarce and seen only in one case; in the second case the tumor was entirely rhabdoid. The differential diagnosis with atypical teratoid/rhabdoid tumors (AT/RTs) and other neoplasms, particularly metastatic carcinoma, was considered. Immunohistochemical and electron microscopic study were critical for the accurate diagnosis of the rhabdoid subtype of meningiomas. Rhabdoid cells stained diffusely positive for vimentin and S-100 protein and showed focal but strong expression of epithelial membrane antigen and cytokeratins. The rhabdoid areas of the tumors exhibited high mitotic activity with a MIB-1 labeling index of 80 - 90%. The diagnosis of rhabdoid meningioma was supported by evidence of SNF5 (INI1) protein expression. Ultrastructural examination demonstrated the presence of interdigitating cell processes joined by numerous desmosomes and paranuclear whorls of intermediate filaments typical of the rhabdoid phenotype. Our two cases of rhabdoid meningiomas were associated with lethal outcome within a few months of initial diagnosis. Extensive necrosis in rhabdoid meningioma might be considered an additional predictor of aggressive clinical behavior.

Image-guided dissection of human white matter tracts as a new method of modern neuroanatomical training.

Neuronavigation is a kind of image-guided surgery used during neurosurgical procedures. Based on specific equipment which is compatible with the software calculating and processing the patient's data; this method allows the determination of the location of anatomical structures and visualisation of surgical instruments in the operative field. Although standard brain dissection is still the best method of neuroanatomical training, some limitations occur. The most important of these is the inability of conversion from three-dimensional (3D) view to flat pictures of the brain structures, as viewed on computed tomography (CT) and magnetic resonance imaging (MRI), being essential in neuroanatomical training nowadays. The aim of the study was the implementation of a neuronavigating system for brain anatomy training purposes. The study was performed on 10 human brain hemispheres, dissected due to classical methods (standard brain anatomical sections, stepwise ventricular system opening and partial dissection of white matter tracts using Klingler's dissection technique). The material was scanned in a 1.5 T magnetic resonance scanner using a modified neuronavigation protocol. The brains were prepared before dissection as proposed by Klingler. The subsequent steps of the dissection were documented with a digital camera. The progress of the dissection was visualised using the neuronavigation system (Medtronic Stealth Station Treon) with cranial application software. In the course of the study, numerous 3D and 2D images were obtained. The images were related to each other and linked anatomical structures in the specimen with their appearance on CT and MRI scans. The implementation of a neuronavigation system for brain structures dissection facilitates visualization and understanding of their proper location. This new method offers a constant and precise orientation and simplifies understanding of the relation of the 3D view of a specimen to that of the 2D image.

[Occipital nerve neuralgia as postoperative complication. Views on etiology and treatment]. / Neuralgia potyliczna jako powiklanie pooperacyjne. Poglady na etiologie i leczenie.

Occipital neuralgia might have a various etiology but the most common cause is hypertrophic fibrosis of subcutaneous tissue following trauma to the occipital region, surrounding the occipital nerve. The other important cause of neuralgia is spondylosis of the upper part of the cervical spine (C1-C2). Rare causes are-diabetes, gout and neoplasm. In the presented material we point out the possibility of the occipital neuralgia after surgery in the treatment of the tumours of ponto-cerebellar region and trigeminal neuralgia. We observed the symptoms in two groups of patients and used pharmacological treatment, local blockade and cutting (neuronectomy) of the occipital nerves trunk when the conservative treatment was unsuccessful. We also present the present concepts of occipital neuralgia treatment. In case of severe symptoms, unsuccessful conservative therapy and poor results of the neuronectomy the most indicated therapy is selective posterior rhizotomy.

Experience with intraoperative high frequency Doppler sonography in neurosurgical practice.

The method of blood flow velocity (BFV) evaluation by intraoperative application of the high frequency Doppler is presented. The device is used to estimate BFV changes in small caliber arteries by direct placement of the probe upon the examined vessel. BFV examinations were performed on the site during aneurysm operations, during transsphenoidal approaches to identify the intracavernous portion of ICA embedded in the tumor mass and in patients after encephalodurosynangiosis evaluated on the outpatient basis. Technical characteristics of the flowmeter used are described and examples of the BFV pictures in cerebral arteries are presented. The device allows a precise BFV evaluation in the selected vessel and detection of changes in BFV patterns particularly useful during aneurysms surgery. This method of identifying cerebral vessels may become applicable in other types of neurosurgical operations.

[The examination of the blood flow velocity in arterial vessel during and after encephalo-dura-arterio-synangiosis. Preliminary results]. / Badania przeplywu krwi w naczyniu tetniczym uzytym do rewaskularyzacji. Encephalo-duro-arterio-synangiosis. (non bypass anastomosis). Doniesienie wstepne.

The Japanese authors first described encephalo-duro-arterio-synangiosis, a new treatment for moya-moya disease, 17 years ago. The other authors used this method (EDAS, indirect anastomosis) in surgical treatment of patients suffered cerebral transient ischaemic attack and cerebral ischaemia. In our department this method was applied in 5 patients with cerebral ischaemia. All patients had internal carotid artery occlusion. After angiography, to localize carotid artery occlusion, acetazolamid (Diamox) test was performed. The patients with negative Diamox test were treated surgically (EDAS). The authors used the intraoperative microdoppler device to monitor blood flow velocity of the prepared vessel (temporal superficial artery) at every stage of surgery. The device was also useful in controlling the patency of encephalo-duro-arterio-synangiosis percutaneously after the surgery. The proximal and the distal part of the non-bypass anastomosis was examined in the follow up during 5-8 months before angiography.