Biomedical subjects

Madjid Samii

Publications and source records attributed to Madjid Samii.

At least 37 records · Page 2Linked to original sources

PubMed2005

High-resolution constructive interference in steady-state imaging in tethered cord syndrome: technical note.

BACKGROUND: Differentiation between nerve roots and the tethered filum terminale in magnetic resonance images remains challenging. It is, however, crucial to select patients for surgical intervention. METHOD: In 1 patient with progressive and 2 patients with stable clinical signs of tethered cord syndrome (TCS), images reconstructed from a 3D constructive interference in steady-state (CISS) sequence were compared with those obtained from a regular T2-weighted fast spin echo sequence. RESULTS: Nerve roots of the cauda equina were suppressed, whereas visualization of the filum terminale was much improved in high-resolution CISS sequences. In addition, the level of adhesion of the filum could be localized in relation to elements of the spinal cord. The imaging results were confirmed during surgery and the patient improved considerably after the intervention. The advantages of CISS were also apparent in 2 other patients who are still being observed. CONCLUSION: Constructive interference in steady-state imaging should be considered in the presurgical routine for patients with TCS.

Adult↗

PubMed2005

Sphenoid wing meningiomas with osseous involvement.

BACKGROUND: Sphenoid wing meningiomas (SWMs) with osseous involvement are neurosurgically challenging because of their position within the skull base and their high rates of recurrence. Sufficient resection of these meningiomas requires extensive surgical exposure. We report on 82 patients with meningiomas infiltrating the sphenoid wing, analyzing radiological appearance and its influence on surgical management. METHODS: Charts of the patients including surgical records, clinical reports, histological examinations, imaging studies, and meticulously focusing questionnaires were reviewed. RESULTS: Among the 82 patients with osseous-involved SWMs, the mean age was 52.2 years in the female group and 54.7 years in the male group with a mean follow-up of 66.23 months (24-206). Histological evaluation revealed World Health Organization grade I meningiomas in 94% of case patients, tumor infiltration of examined bone in all case patients, and proliferation rates of 2.2% Ki-67. Magnetic resonance imaging appearance of the SWMs demonstrated various densities as well as Gd enhancement within the affected bone. Recurrence rates in this subgroup of SWMs are higher (>30%) compared with meningiomas without osseous involvement (11.6%). CONCLUSION: Osseous involvement in SWMs accounts for lower resection and higher recurrence rates than meningiomas in other locations. In those cases with involvement of the cavernous sinus, a subtotal but extensive removal combined with bony decompression of the cranial nerves at the superior orbital fissure and optic canal frequently produces good functional and cosmetic results.

Adult↗

PubMed2005

Epidermoid cysts of the cavernous sinus.

BACKGROUND: Epidermoid cysts involving the cavernous sinus are rare lesions. They can be divided into 3 different categories: extracavernous, interdural, and true intracavernous. METHODS: This classification of cavernous epidermoid cysts is correlated with the extent of tumor resection and the clinical outcome in reported cases here and elsewhere. RESULTS: Patients with cysts invading or compressing the cavernous sinus present with an excellent functional recovery after surgery independent of the extent of tumor resection. In cases of interdural cysts, there is often an adherence of the tumor capsule to the third and fourth cranial nerves. Therefore, in this group, subtotal resection is a safe strategy to prevent surgical morbidity. However, this policy may lead to a higher incidence of tumor recurrence in these cases. In true intracavernous lesions, a higher rate of total removal is possible despite the increased occurrence of internal carotid artery encasement and cranial nerve displacement. CONCLUSION: Postoperative outcome with preservation of neural and vascular structures in cavernous epidermoid cysts is more likely related to surgical strategy than to tumor localization. Independent of the different tumor origins in these cases, a subtotal resection is usually sufficient to achieve postoperative improvement of the symptoms without additional morbidity.

Adult↗

PubMed2005

Facial and cochlear nerve function after surgery of cerebellopontine angle meningiomas.

OBJECTIVE: Meningiomas of the cerebellopontine angle (CPA) share a common location, but their site of dural origin and their relationship to surrounding neurovascular structures of the CPA are variable. The clinical presentation and outcome after surgical resection are different because of the diversity of this tumor entity. We report on a series of 421 patients with CPA meningiomas, with special emphasis on the analysis of the preoperative and postoperative facial and cochlear nerve function in relation to the site of dural attachment and main tumor location in the CPA cistern. METHODS: Among 421 patients, the charts of 347 patients with complete clinical data, including the history and audiograms, imaging studies, surgical records, discharge letters, histological records, and follow-up records, were reviewed retrospectively. Data about preoperative and postoperative facial nerve function were available in 334 patients, and audiometric analysis was conducted in 333 patients. Patients with neurofibromatosis Type 2 were excluded from the study. RESULTS: There were 270 women and 77 men, with a mean age of 53.4 years (range, 17.6-84 yr). Among these patients, 32.9% of the tumors originated at the petrous ridge anterior to the inner auditory canal (IAC) (Group 1), 22.2% showed involvement of the IAC (Group 2), 20.2% were located superior to the IAC (Group 3), 11.8% were inferior to the IAC (Group 4), and 12.9% were posterior to the IAC, originating between the IAC and the sigmoid sinus (Group 5). Patients presented with disturbance of Cranial Nerves V-VIII, the lower cranial nerves, and ataxia, depending on the main tumor location. Tumor resection was performed through a suboccipital-retrosigmoidal approach in the semisitting position in 95% of the patients. A combined supratentorial-infratentorial presigmoidal approach was performed in 5%. Total tumor removal (Simpson Grade 1 and 2) was achieved in 85.9% and subtotal removal in 14.1%. The best initial postoperative facial and auditory nerve function was observed in tumors belonging to Groups 3 and 5. Recovery from preoperative deafness was observed in 1.8% of patients. On long-term follow-up, good facial nerve function (House-Brackmann Grade 1 or 2) was observed in 88.9% of patients. Hearing preservation among patients with preoperative functional hearing was documented in 90.8% on long-term follow-up. CONCLUSION: Although the outcome of facial and cochlear nerve function is different in CPA meningiomas, depending on the topographic classification of these tumors, preservation of the cochlear nerve is possible in every tumor group and should be attempted in every patient with CPA meningioma. It has to be kept in mind that recovery of hearing was also observed in patients with preoperative profound hearing deficits.

Adolescent↗

PubMed2005

Volumetric image guidance for motor cortex stimulation: integration of three-dimensional cortical anatomy and functional imaging.

OBJECTIVE: Epidural electrical stimulation of the motor cortex is a promising treatment option in patients with intractable pain. Varying rates of success in long-term pain relief have been attributed to inaccurate positioning of the electrode array, partly because the sulcal landmarks are not directly visualized. We describe an integrated protocol for precise electrode placement, combining functional image guidance and intraoperative electrical stimulation in the awake patient. METHODS: Volumetric rendering of a three-dimensional (3-D) magnetic resonance data set was used to visualize the cortical surface and to superimpose functional magnetic resonance imaging data in six patients with refractory chronic pain. The intraoperative positioning of the quadripolar electrode array was monitored by functional 3-D image guidance. Continuous electrophysiological monitoring and clinical assessment of the motor effects complemented the procedure. RESULTS: Volumetrically rendered 3-D images were advantageous for the location of the burr hole over the perirolandic area by revealing individual cortical morphological features (e.g., the hand knob) and function at the same time. The exact position of the electrodes was verified reliably by cortical stimulation. No complications were observed throughout the procedures. CONCLUSION: The combination of 3-D functional neuronavigation, intraoperative electrical stimulation, and continuous motor output monitoring in awake patients provides optimal information for the identification of the appropriate somatotopic area of motor cortex. This combined imaging and stimulation approach for electrode positioning offers a safe and minimal invasive strategy for the treatment of intractable chronic pain in selected patients.

Adult↗

PubMed2005

Nausea and dizziness after vestibular schwannoma surgery: a multivariate analysis of preoperative symptoms.

OBJECTIVE: Nausea and dizziness are very discomforting for patients after vestibular schwannoma surgery and they impair recovery. METHODS: To identify preoperative symptoms and conditions that increase the risk of development of nausea after vestibular schwannoma surgery, a multivariate analysis was performed. One hundred fifteen patients with vestibular schwannoma had a microsurgical tumor removal in a standardized procedure in 2001 and 2002. Eighteen patients were excluded from the study because of previous surgery (recurrent tumors, 7 patients) or bilateral tumor occurrence (neurofibromatosis, 11 patients). Analysis was performed regarding postoperative amount of antiemetic medication, vomiting, and subjective feeling of the patient. Tumor grading, body mass index, sex, previous complaints, examination at admission, and side of the tumor were taken in consideration. RESULTS: Women had significant longer postoperative complaints (mean, 3.0 d; standard error, 0.47) and needed longer antiemetic therapy (mean, 3.3 d; standard error, 0.49) than men (mean, 1.72 d; standard error, 0.21). Patients developing no significant postoperative complaints were all in the higher tumor grading group, Grades 3a, 4a, and 4b. There was a significant difference in the duration of antiemetic therapy between tumors graded 1 and tumors graded 3 or 4. Patients with a positive stepping test preoperatively had a tendency to demand less antiemetic medication. Women with small tumors are most likely to develop significant complaints after vestibular schwannoma surgery. CONCLUSION: It is possible to identify patients with a higher risk of postoperative nausea and dizziness after vestibular schwannoma surgery. This allows one to inform these patients preoperatively and to initiate an early postoperative drug therapy to ease their symptoms.

Adult↗

PubMed2005

Meningiomas of the cerebellopontine angle with extension into the internal auditory canal.

OBJECT: Only some meningiomas of the cerebellopontine angle (CPA) extend into the internal auditory canal (IAC) or arise from its dural lining. The authors investigated cases of CPA tumors in which the meningioma was inserted in the dura mater in or at the ICA or infiltrated a cranial nerve. METHODS: The authors reviewed patient charts including surgical and clinical records, intraoperative recordings of auditory evoked potentials, records of postoperative auditory examinations, and imaging studies. In a series of 421 patients harboring CPA meningiomas, 72 patients in whom there was dural involvement of the IAC were investigated. Total tumor resection was achieved in 86.1%. In 34 patients, opening of the IAC was required for total tumor removal; this procedure did not influence the patient functional outcome. Among patients with secondary involvement of the IAC, anatomical preservation of the facial and cochlear nerves was obtained in 94%, whereas among patients in whom the lesion arose from the dura in or at the IAC these values were 80 and 75%, respectively. Functional preservation of the seventh and eighth cranial nerves in cases of tumor extension within the IAC was 86 and 77%, respectively, whereas in cases in which the IAC was involved it was only 60%. In four of five patients in whom the tumor had its origin in the dura mater within the IAC, the seventh or eighth cranial nerve had to be sacrificed to achieve tumor removal because of the lesion's infiltrative behavior. Facial nerve reconstruction by sural grafting was performed in the same operative procedure. CONCLUSIONS: Meningiomas of the CPA involving the IAC require special surgical management. Dural involvement of the IAC requires opening by using a diamond drill, a procedure that does not influence cranial nerve outcome. The increased rate of cranial nerve morbidity is attributed to the infiltrative behavior of these meningiomas. If affected nerve segments have to be sacrificed, immediate reconstruction enables satisfactory long-term results.

Adult↗

PubMed2005

Intraoperative auditory brainstem responses in patients with cerebellopontine angle meningiomas involving the inner auditory canal: analysis of the predictive value of the responses.

OBJECT: Meningiomas of the cerebellopontine angle (CPA) can either arise from or secondarily grow into the inner auditory canal (IAC). This location may have a great impact on hearing function following surgery to remove these lesions. The aim of this retrospective study was to investigate the reliability and predictive importance of auditory brainstem responses (ABRs) for the determination of postoperative auditory function in patients with CPA meningiomas in comparison with results obtained in patients who undergo surgery for vestibular schwannomas. METHODS: In a consecutive series of 1800 meningiomas surgically treated between 1978 and 2002, 421 lesions were located in the CPA. In 38 patients with CPA meningiomas involving the IAC, the findings of intraoperative ABR monitoring and the hearing status of each patient before and after surgery were retrospectively analyzed. On analysis, ABR monitoring demonstrated stable findings in 24 patients throughout tumor resection and fluctuating signals in 10 patients. Among the 24 patients with stable ABRs, postoperative hearing function improved in three patients, remained the same in 15, and worsened in six patients, including one patient who displayed postoperative deafness. There was even one patient recovering from preoperative deafness. Among the 10 patients with unstable ABRs, intermittent decreases in amplitude and deformations of variable duration in the ABR wave were noted. The risk of deafness was considerably higher in patients with prolonged phases of intermittent ABR deterioration. CONCLUSIONS: The presence and absence of ABRs during surgery for CPA meningiomas reliably predicted the presence and absence of postoperative auditory function. Intermittent deterioration of ABRs may result in postoperative deafness, depending on the duration of these events during surgery. Improvements in hearing are only seen when the ABRs are stable for amplitudes and latencies throughout surgery.

Adult↗

PubMed2005

Evaluation of a new concept for the management of skull base chordomas and chondrosarcomas.

OBJECT: Chordomas and chondrosarcomas of the skull base are rare locally invasive tumors associated with high recurrence rates. The aim of this study was to evaluate the concept of microsurgical tumor volume reduction followed by early gamma knife surgery (GKS). METHODS: Thirteen patients with 15 tumors were treated between October 2000 and June 2003. There were three patients (23.1%) with chordomas and 10 (76.9%) with chondrosarcomas. There were nine men and four women who ranged in age between 19 and 69 years. All patients first underwent maximal tumor resection. Within 2 to 10 months after surgery they were treated with GKS. The mean postoperative tumor volume treated with GKS was 9.7 cm3 (range 1.4-20.3 cm3). Follow-up computerized tomography and magnetic resonance imaging examinations with volumetric tumor analysis were performed every 6 months after GKS. The mean treatment dose was 17 Gy and the mean isodose was 52%. The mean follow-up duration was 17 months during which there was only one tumor recurrence at the margin of the radiation field. The mean volume reduction was 35.4%. CONCLUSIONS: Results of this treatment strategy are encouraging but the efficacy of this multimodal treatment combining surgery and early GKS requires a longer follow up.

Adult↗

PubMed2005

Volume reduction in meningiomas after gamma knife surgery.

OBJECT: The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment. METHODS: A group of 127 patients with a mean age of 57.1 years (range 9-81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter. The mean tumor volume was 5.9 cm3 (range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11-61 months). The mean prescription dose was 13.8 Gy (range 10-18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) stowed a volume increase. CONCLUSIONS: Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.

Adolescent↗

PubMed2005

Frameless free-hand maneuvering of a small-diameter rigid-rod neuroendoscope with a working channel used during high-resolution imaging. Technical note.

A newly designed small-diameter rigid-rod neuroendoscope was created to evaluate the applicability of free-hand maneuvering during high-resolution imaging. The neuroendoscope was designed as a light, handheld tool weighing 550 g. A 20-cm-long objective lens, 2 mm in diameter, is placed in the lower two thirds of the single-space lumen of an oval-shaped outer sheath, 16.5 mm long and 3.5 x 2.5 mm at maximum diameter. Included are microinstruments of 1.3-mm diameter for various neuroendoscopic procedures, including microscissors, biopsy forceps, grasping forceps, monopolar coagulator/cutting rod, and bipolar coagulator that can be introduced through the upper one third of the lumen. Because the endoscope is held steady in the surgeon's left hand, with the handle gripped at the base, quick back-and-forth movements can be made along the long axis, via a peel-away sheath inserted to the ventricle, shifting of the endoscope tip to the side of the objective target will be minimal. Given the instrument's unified configuration, the surgeon will never lose orientation during maneuvering. Using the farthest right of three inlet/outlet orifices, the short and handy semiflexible microinstruments can be guided and controlled by the surgeon's right hand. After experience in 66 cases in which various neuroendoscopic procedures yielded excellent operative outcomes (morbidity rate in complications related to the endoscopic procedure 0%; mortality rate 0%), the endoscope prototype was finalized in the ideal form for frameless maneuvering that uses a rigid-rod endoscope. The "gun-butt" holder for use with the operator's left hand provides stability and allows the endoscope to be handled with improved control. These new aspects of the neuroendoscope and surgical technique offer substantial improvement over the flexible-steerable fiberoptic endoscopes.

Equipment Design↗

PubMed2004

Ultrastructure of the cerebrospinal fluid outflow along the optic nerve into the lymphatic system.

OBJECT: To explain the spontaneous CSF outflow into the orbit, the ultrastructure of the perineural meningeal layers at the distal and the proximal portions of the optic nerve were compared. METHODS: Ten cats were perfusion fixated and the orbital content removed for transmission and scanning electron microscopy. In five animals a 60-min cisternal infusion of contrast medium at low intracranial pressure was performed before perfusion fixation. RESULTS: In the contrast-infused animals it was possible to demonstrate the leakage of contrast medium in the distal portion of the optic nerve sheath (ONS) from the subarachnoid space (SAS) into the orbit and find it in the conjunctival lymphatics. Electron microscopy revealed that in the distal portion of the ONS the neurothelial layers are significantly thinner, some consisting of only one layer. Pore-like openings in the neurothelial covering are seen in the distal portion. Excavations of the SAS are far more numerous in the distal portion of the ONS. The excavations reach the neurothelial layer. Intracellular and extracellular filaments are more numerous in the distal portion of the ONS. There is no significant difference in the dura mater between the distal and proximal ONS. The results show the existence of an arachnoid window area in the distal portion of the ONS. It is characterised by a continuous, but thinned neurothelial barrier layer, with few pore-like openings. CONCLUSIONS: The main differences between distal and proximal ONS are a thinned neurothelial barrier layer and an increased number of intercellular filaments and pore-like openings. The findings explain the lymphatic CSF outflow pathway along the optic nerve.

Animals↗

PubMed2004

Specially adapted interactive tools for an improved 3D-segmentation of the spine.

For imaging purposes of the spine, segmented image data provides the basis for a variety of modern clinical applications. However, the anatomical complex structure of the spine as well as the extensive degenerative bony deformations apparent in the clinical situation, generally complicate the application of a fully automated segmentation. To serve the special needs for image segmentation of the spine anatomy a newly developed software system is presented, that implements specially adapted interactive tools, taking its 'axis'-skeletal structure into account. A standardized protocol combines the newly developed interactive tools (rotation transformation, warped dissection plane) with standard segmentation tools to provide both a fast and accurate segmentation procedure. The introduced software environment has been valuable for the segmentation of cervical, thoracic and lumbar spines segments based on clinical routine and research images.

Computers↗

PubMed2004

Apoptosis, vascularity, and proliferation in primary central nervous system lymphomas (PCNSL): a histopathological study.

BACKGROUND: In the present study apoptosis, vascularity, and proliferation were quantitatively analyzed with immunohistopathological techniques in primary central nervous system lymphomas (PCNSL). Statistical analysis of these parameters was performed to evaluate their possible relationship with the unfavorable outcome of this tumor. METHODS: A series of 32 PCNSL patients for a total of 33 tumors treated from 1984 to 2000 in the Neurosurgical Department were reviewed, and their histologic specimens examined for apoptosis, vascularity, and proliferation. RESULTS: Patients were treated with either gross total/subtotal tumor removal or stereotactic biopsy. Vascularity was studied by means of FVIII staining, proliferative index with Ki-67 staining, and apoptosis with the TUNEL technique. Most tumors could be classified as immunoblastic or centroblastic B-Cell NHL. Mean Mib-1 Labeling Index was 35.34% (5-80), blood vessel density of 40.8 per 10 high power fields. Apoptotic cells were zero or less than 8 cells per 10 high power fields. CONCLUSION: No statistically significant correlation between survival and histopathological parameters could be shown. However, the apoptosis index was found to be negatively correlated with proliferative index and may account for a more aggressive clinical course of PCNSL.

Adult↗

PubMed2004

Intralesional mitoxantrone biopolymer-mediated chemotherapy prolongs survival in rats with experimental brain tumors.

The present study was designed to test the efficacy of intratumoral biopolymer-mediated mitoxantrone chemotherapy in the rat brain 9L glioma model. Mitoxantrone polymers were tested in vitro in 9L and C6 cell cultures for 10 days. Subsequently, adult Fisher 344 rats were implanted with 5 x 10(4) 9L glioma cells in the frontal region of the brain. In a first experiment, 2 days after cells inoculation, one group of rats were implanted with a biopolymer loaded with 4 mg of mitoxantrone at the tumor site. A second group of rats received drug-free biopolymers and served as controls. In a second experiment, rats were implanted with a biopolymer loaded with 2 mg of mitoxantrone. Another group of rats received 2 mg of mitoxantrone intraperitoneally. Controls received drug-free biopolymers. Rats were sacrificed as soon as they developed progressive neurological deficits. In the first experiment mean survival of mitoxantrone-treated rats was 10+/-2 vs. 15+/-2 days for the control group (P = 0.0003). Early morbidity was seen in 60%, and impaired wound healing was seen in 40% of the 4 mg mitoxantrone treated animals. In the second experiment mean survival of mitoxantrone-treated rats was significantly longer than that of the control group (P < 0.0001) with 33+/-7 vs. 13.8+/-2 days for the control group. Only transient early morbidity (20%) was observed at this dose. All rats in the intraperitoneally mitoxantrone-treated group died within the first 4 days after injection. We conclude that controlled-release EVAc carriers deliver biologically active mitoxantrone in a sustained fashion. In vivo biopolymer-mediated mitoxantrone in loco chemotherapy can significantly prolong survival in rats with intracerebral 9L gliomas. Morbidity is mainly dose related, and can be reduced at acceptable levels without compromising the therapeutic effect.

Animals↗

PubMed2004

Biopolymer-mediated suramin chemotherapy in the treatment of experimental brain tumours.

Suramin inhibits tumour growth and neoangiogenesis by blocking several growth factor receptors. In this study the toxicity and efficacy of intralesional delivery of suramin incorporated in a controlled-release polymer were assessed in a rat 9L tumour model. Initially, the toxicity of the compound was evaluated in adult Fisher 344 rats. The animals were intracerebrally implanted with an ethylene vinyl acetate copolymer. These experiments showed early toxicity in the rats implanted with a 50% load-polymer and 100% mortality within 48 h, whereas in rats implanted with a 33% load-polymer only transient behavioural changes were observed. In a second experiment the rats were stereotactically implanted with 9L cells in the frontal region. Two days after inoculation of cells, the animals were divided into two groups: one group received a 33% suramin load-biopolymer at the tumour implantation site, while the control group received polymer implants only. The interstitial release of suramin in the brain did not produce any improvement in survival of 9L tumour-bearing rats, with a mean survival of 14.2 +/- 1 days for the suramin-treated group versus 13.8 +/- 2 for the control group (p = 0.82). We conclude that intralesional polymer-mediated chemotherapy with suramin does not prolong survival in rats with intracerebral 9L tumours.

Animals↗

PubMed2004

Meningiomas of the internal auditory canal.

OBJECTIVE: Meningiomas arising primarily within the internal auditory canal (IAC) are notably rare. By far the most common tumors that are encountered in this region are neuromas. We report a series of eight patients with meningiomas of the IAC, analyzing the clinical presentations, surgical management strategies, and clinical outcomes. METHODS: The charts of the patients, including histories and audiograms, imaging studies, surgical records, discharge letters, histological records, and follow-up records, were reviewed. RESULTS: One thousand eight hundred meningiomas were operated on between 1978 and 2002 at the Neurosurgical Department of Nordstadt Hospital. Among them, there were 421 cerebellopontine angle meningiomas; 7 of these (1.7% of cerebellopontine angle meningiomas) were limited to the IAC. One additional patient underwent surgery at the Neurosurgical Department of the International Neuroscience Institute, where a total of 21 cerebellopontine angle meningiomas were treated surgically from 2001 to 2003. As a comparison, the incidence of intrameatal vestibular schwannomas during the same period, 1978 to 2002, was 168 of 2400 (7%). There were five women and three men, and the mean age was 49.3 years (range, 27-59 yr). Most patients had signs and symptoms of vestibulocochlear nerve disturbance at presentation. One patient had sought treatment previously for total hearing loss before surgery. No patient had a facial paresis at presentation. The neuroradiological workup revealed a homogeneously contrast-enhancing tumor on magnetic resonance imaging in all patients with hypointense or isointense signal intensity on T1- and T2-weighted images. Some intrameatal meningiomas showed broad attachment, and some showed a dural tail at the porus. In all patients, the tumor was removed through the lateral suboccipital retrosigmoid approach with drilling of the posterior wall of the IAC. Total removal was achieved in all cases. Severe infiltration of the facial and vestibulocochlear nerve was encountered in two patients. There was no operative mortality. Hearing was preserved in five of seven patients; one patient was deaf before surgery. Postoperative facial weakness was encountered temporarily in one patient. CONCLUSION: Although intrameatal meningiomas are quite rare, they must be considered in the differential diagnosis of intrameatal mass lesions. The clinical symptoms are very similar to those of vestibular schwannomas. A radiological differentiation from vestibular schwannomas is not always possible. Surgical removal of intrameatal meningiomas should aim at wide excision, including involved dura and bone, to prevent recurrences. The variation in the anatomy of the faciocochlear nerve bundle in relation to the tumor has to be kept in mind, and preservation of these structures should be the goal in every case.

Adult↗

PubMed2004

Transition from meningeal melanocytoma to primary cerebral melanoma. Case report.

The authors describe the first case of an intracranial transition of a melanocytoma into a primary malignant melanoma within a short time. A 37-year-old woman presented with progressive brainstem syndrome due to a tumor, originally diagnosed and treated 12 years earlier, that extended from the petroclival area to the anterior craniocervical junction. The histological workup following subtotal tumor resection of the initial tumor had revealed the typical features of a fibrous melanocytic meningioma without increased proliferation. Ten years after the patient had completed treatment for the melanocytic meningioma, control neuroimaging demonstrated growth of the residual tumor with compression of the brainstem. Another neurosurgical intervention revealed a dark tumor of hard consistency. At this time immunohistochemical examinations demonstrated melanocytic features (expression of vimentin, S100 protein, and melan A) of the lesion with focally increased proliferation (5% of Ki-67-positive cells) but no higher mitotic activity. Clinical signs of deterioration along with imaging-confirmed tumor progression precipitated another operation within 7 months. A neuropathological examination revealed epithelial and anaplastic changes and indicated that the MIB-1 indices were greater than 25%. Pleomorphic changes and a focal high mitotic activity led to the diagnosis of a primary cerebral malignant melanoma. The patient's later clinical course consisted of a rapid diffuse meningeal spread of the lesion throughout the entire brain and spine. Despite whole-brain and stereotactic radiation therapy as well as chemotherapy, the patient died 4 months after the last neuropathological diagnosis. Although grossly resembling a meningioma, melanocytomas lack the former's histological and immunohistochemical features. The biological behavior of a melanocytoma is variable and recurrence may happen after subtotal resection, but intracranial transition into a malignant melanoma has not been observed previously.

Adult↗