P.-H. Roche

Gamma knife radiosurgical management of petroclival meningiomas results and indications.

Summary¶Background. Surgical treatment of petroclival meningiomas remains challenging. In order to refine indications for the use of stereotactic radiosurgery in the treatment of these tumours, we retrospectively evaluated our experience in this field. Methods. Thirty-two patients harboring a petroclival meningioma were treated consecutively using a Gamma knife between December 92 and June 1998. Eight patients underwent radiosurgery after one or more attempted surgical removals and 24 had radiosurgery as the primary treatment. The main symptoms before radiosurgery were cranial nerve palsies, including a sixth nerve deficit in 10 patients and a trigeminal nerve disturbance in 9. All patients underwent a conformal multi-isocentric treatment (mean isocenter’s number 8.8) and the dose delivered at the tumour margin ranged from 10 to 15 Gy (mean dose 13 Gy). Findings. The duration of follow-up varied from 24 to 118 months (mean clinical follow-up 56 months, mean radiological follow-up 52.6 months). All 32 patients survived. The tumour volume remained unchanged in 28 patients and decreased slightly in 4. Neurological status worsened permanently in 2 patients with a delayed hemiparesis due to focal pontine infarction. These complications were associated with large meningiomas with vascular involvement and ventral brainstem compression, and occurred at the very early stage of our experience. At last follow-up, preoperative fifth or sixth cranial nerve deficits had improved or recovered in 13 out of 19 patients and any delayed worsening or new cranial nerve deficits were not observed after radiosurgery. Conclusions. Stereotactic radiosurgery with a Gamma knife provides effective management of small to middle sized petroclival meningiomas and is an alternative to microsurgery. Careful selection of patients and use of major technical refinements should improve the safety of this treatment.

Endolymphatic sac tumors: report of three cases.

OBJECTIVE AND IMPORTANCE We present three cases of endolymphatic sac tumors and review the previously published cases. Despite frequent extension to the cerebellopontine angle, these rare tumors have only recently been recognized by neurosurgeons. CLINICAL PRESENTATION A 26-year-old man developed a progressive hearing loss, revealing an intrapetrous retrolabyrinthine tumor on the right side. A 28-year-old woman experienced a left cerebellopontine angle syndrome, with a lytic intrapetrous mass extending into the cerebellopontine angle. A 38-year-old woman presented with an intracranial hypertension syndrome caused by a tumor of the jugular foramen. INTERVENTION For the first and second patients, the tumors originated from the operculum of the endolymphatic sac. Total removal was achieved, via a transpetrosal approach, in these two cases. No recurrence was detected after a 20-month follow-up period. For the third patient, the tumor originated from the distal part of the sac. Recurrence was observed 8 years after subtotal removal via a retrosigmoid route. Histological analysis revealed a papillary-cystic adenocarcinomatous pattern in all cases, without features of aggressiveness. CONCLUSION Endolymphatic sac tumors are locally invasive neoplasms characterized by bipolar intrapetrous and posterior fossa involvement. The anatomic complexity of the endolymphatic sac may explain the distinct patterns of extension of these tumors. Early radical surgery is related to good outcomes.

Crowned dens syndrome: a manifestation of hydroxy-apatite rheumatism.

SummaryCrowned dens syndrome is defined as an association of acute cervical pain and calcifications in the peri-odontoid space. The authors report one case of this rare localization of hydroxy-apatite rheumatism and review 12 similar cases in the literature. This disease affects only adult females. Patients present with inflammatory signs, can be treated with non-steroid anti-inflammatory drugs and recover without sequela. Calcium pyrophosphate dihydrate deposition can also lead to this syndrome. Other perioodontoid calcifications and ossifications, usually asymptomatic, appear only as a radiologically crowned dens.

Expression of cell adhesion molecules in normal nerves, chronic axonal neuropathies and Schwann cell tumors

Cell adhesion molecules (CAMs) play a role in the normal development and regeneration of tissues as well as in the biological behaviour of tumors. We studied the immunohistochemical expression of various CAMs, such as neural cell adhesion molecule (NCAM), its polysialylated isoform (PSA-NCAM), epithelial (E-) cadherin, and beta1 integrins (alpha2beta1, alpha5beta1, alpha6beta1) in a series of frozen specimens of 10 normal nerves, 5 axonal neuropathies, 26 benign Schwannomas and 2 malignant peripheral nerve sheath tumors (MNST). NCAM was expressed by non-myelinating Schwann cells from normal nerves and overexpressed by Schwann cells from patients with chronic axonal neuropathies and Schwannomas. The expression was lower in MNST. Expression of PSA-NCAM was heterogeneously displayed by Schwann cells from the various tissues studied. Anti E-cadherin immunoreactivity was present in myelin sheath in normal nerves and axonopathies. It was expressed in some Schwannomas especially in vestibular Schwannomas. Integrins VLA alpha2 and VLA alpha6 were widely expressed by Schwann cells from normal nerves, axonal neuropathies and Schwannomas but their expression was low in MNST. VLA alpha5 was not expressed by Schwann cells from normal nerve and Schwannomas but present in chronic axonal neuropathies and MNST. In addition VLA alpha6 was strongly expressed by perineurial cells. These data show that CAMs have a characteristic pattern of expression in normal nerve. Also, some CAMs are always expressed by Schwann cells but the expression of others differs in normal nerves versus axonopathies or tumors, suggesting a role of the microcellular environment in the regulation of CAM expression. Schwannomas have different pattern of expression than MNST.

Cauda equina paraganglioma with subsequent intracranial and intraspinal metastases

SummaryA case of cauda equina paraganglioma is described; subsequent intracranial and intraspinal metastases occurred after partial resection and adjunctive radiotherapy. Cerebrospinal fluid dissemination is a rare complication of spinal paragangliomas. Factors predictive of this unusual biological behaviour are discussed.

High jugular bulb in the translabyrinthine approach to the cerebellopontine angle: anatomical considerations and surgical management

SummaryBackground. Evidence of a high jugular bulb position (HJBP) during the translabyrinthine approach may compromise the surgical removal of cerebellopontine angle (CPA) tumours. We report a simple surgical procedure to safely manage this frequent normal variation and comment on various alternative options.Methods. The translabyrinthine approach included a complete skeletonization of the sigmoid sinus and of the presigmoid dura. A thin eggshell bone was left at the jugular bulb surface. The dome of the jugular bulb was gently dissected from the jugular fossa and gradually retracted downward in a tailored way, allowing the surgeon to drill below the internal auditory meatus. A small piece of bone was wedged over the jugular dome in order to maintain its lowered position.Results. Among 178 consecutive translabyrinthine approaches performed for the removal of large CPA tumors, the use of this procedure was required in 44 cases of HJBP. Excepting minimal venous bleeding easily controlled in several cases, we never observed any complication from this procedure nor failure to expose the inferior compartment of the CPA.Conclusions. The HJBP can be systematically diagnosed with the preoperative CT-scan using bone window imaging. Our results demonstrate that the described procedure is safe and effective to widen the operative corridor that is required for the exposure of the inferior compartment of the CPA in this anatomical situation.

Giant central neurocytoma with tetraventricular and extra-axial extension

SummaryThe central neurocytoma is a recently recognized benign intraventricular tumour of young adults. The authors report a unique case of a panventricular neurocytoma with extension to the interpeduncular and prepontique cisterns which developed in a 35-year-old woman with a 7-year history of headaches and amenorrhea. They review the different pathological and topographical patterns of previously published neurocytomas and discuss the histogenesis of this rare tumour.

Two- and three dimensional measures of vestibular schwannomas and posterior fossa--implications for the treatment.

SummaryBackground. There is no uniformly accepted method of reporting the size of vestibular schwannomas (VS) and to evaluate the individual tumour behaviour in the posterior fossa (PF). To help the treatment decision we investigated the VS and PF morphometry using a computerized method. Method. Stereotactic fused CISS MR and CT scan images were obtained from 58 adult patients (31 males and 27 females) harbouring an unilateral VS (25 Koos II, 21 Koos III and 12 Koos IV). Using a Gammaplanworking station we screened for the following measures: anteroposterior (AP), craniocaudal (CC), transverse (T) and maximum (Max) diameters (Diam) of the intracisternal part of the tumour, VS and PF volumes. Findings. The Max Diam was the most accurate way to estimate the tumour volume (Spearman’s rho >0.80). Among several parameters, the T Diam was the best measure to assess the brain shift (ROC analysis) with a cut off value at 14.5 mm (91.7% sensitivity and 93% specificity). VS volume and the ratio VS volume/PF volume were also efficient to predict a brain shift. Conclusions. Max Diam and T Diam are bedside measured simple data of particular interest to respectively estimate the VS volume and predict the brain shift due to the tumour. The determination of cut-off values correlated to brain shift will provide guidelines at the time of the therapeutic decision between radiosurgical and microsurgical strategy.

Mixed meningeal and brain plasma-cell granuloma: an example of an unusual evolution.

SummaryWe report a study of a 22-year-old woman with a plasma-cell granuloma (PCG), a rare intracranial lesion characterized by a non-neoplastic polyclonal proliferation of plasma cells and other mononuclear cells. She presented after a generalized seizure and CT-scan and magnetic resonance images demonstrated a left temporo-basal tumour mass involving both the meningeal layers and the brain parenchyma. Histopathological examination of a biopsy led to the diagnosis of a typical PCG. After a short course of steroid administration, the clinical and radiological features improved and complete regression of the lesion was shown after one year and persisted at four-year follow-up. This dramatic regression of an intracranial PCG shows that neither surgical removal nor radiation therapy is required to treat a broad skull base PCG.

Natural course and prognosis of anaplastic gangliogliomas: a multicenter retrospective study of 43 cases from the French Brain Tumor Database

Background Anaplastic gangliogliomas (GGGs) are rare tumors whose natural history is poorly documented. We aimed to define their clinical and imaging features and to identify prognostic factors. Methods Consecutive cases of anaplastic GGGs in adults prospectively entered into the French Brain Tumor Database between March 2004 and April 2014 were screened. After diagnosis was confirmed by pathological review, clinical, imaging, therapeutic, and outcome data were collected retrospectively. Results Forty-three patients with anaplastic GGG (median age, 49.4 y) from 18 centers were included. Presenting symptoms were neurological deficit (37.2%), epileptic seizure (37.2%), or increased intracranial pressure (25.6%). Typical imaging findings were unifocal location (94.7%), contrast enhancement (88.1%), central necrosis (43.2%), and mass effect (47.6%). Therapeutic strategy included surgical resection (95.3%), adjuvant radiochemotherapy (48.8%), or radiotherapy alone (27.9%). Median progression-free survival (PFS) and overall survival (OS) were 8.0 and 24.7 months, respectively. Three- and 5-year tumor recurrence rates were 69% and 100%, respectively. The 5-year survival rate was 24.9%. Considering unadjusted significant prognostic factors, tumor midline crossing and frontal location were associated with shorter OS. Temporal and parietal locations were associated with longer and shorter PFS, respectively. None of these factors remained statistically significant in multivariate analysis. Conclusions We report a large series providing clinical, imaging, therapeutic, and prognostic features of adult patients treated for an intracerebral anaplastic GGG. Our results show that pathological diagnosis is difficult, that survivals are only slightly better than for glioblastomas, and that complete surgical resection followed with adjuvant chemoradiotherapy offers longer survival.