Florian H. Ebner

Differentiating imaging findings in primary and secondary tumors of the jugular foramen

The preoperative diagnosis of a jugular foramen tumor may be challenging, since a large variety of unusual lesions may be located in this region. These tumors may be classified as primary lesions (which are located in the jugular foramen or extend from the jugular foramen into the surrounding structures) and as secondary lesions (that extend from the surrounding structures into the jugular foramen). Primary tumors include glomus jugulare tumors, schwannomas, meningiomas and peripheral primitive neuroectodermal tumors, while secondary tumors comprise chordomas, chondrosarcomas, chondroblastomas, giant-cell tumors, cholesterol granulomas, giant cholesterol cyst, endolymphatic sac tumors, reactive myofibroblastic tumors, temporal bone carcinomas and metastases. Accurate preoperative radiological suspicion is of great value for preoperative patient counseling and has a direct impact on the surgical planning in these cases. The present study describes and discusses the main differentiating imaging features of lesions involving the jugular foramen, whose accurate preoperative radiological evaluation is essential for proper surgical planning.

Management of skull based meningiomas in the elderly patient

BACKGROUND The demographic evolution of Western society together with availability of modern imaging techniques leads to an increasing diagnosis of meningioma patients over 70 years of age. This raises the question of appropriate management of this histologically benign tumour in a geriatric population. DESIGN Forty-three patients aged over 70 years were analyzed and matched in a retrospective study with a younger group of 89 patients according to tumour size, histology, symptoms, recurrence and presence of neurofibromatosis II. RESULTS Changes in postoperative Karnofsky scores were not statistically different between the two age groups. Neurological outcome was worse among the younger group (12% vs. 7% deterioration). Regarding surgical complications we noted only a statistically significant higher infection rate in the geriatric age group. There was no peri-operative mortality. CONCLUSIONS Age alone is not a criterion to deny a priori skull base surgery, since well selected geriatric patients may benefit from a meningioma operation that may enhance future quality of life.

Pituicytoma in a patient with Cushing's disease: case report and review of the literature

Pituicytoma is an exceptionally rare low-grade glioma (WHO grade I) of the neurohypophysis and infundibulum. We are reporting the case of a 48-year-old man who presented with severe Cushing′s syndrome. Endocrinological evaluation unequivocally confirmed pituitary-dependent Cushing’s syndrome (=Cushing’s disease). Cranial MR-imaging displayed a conspicuous area in the dorsal and basal pituitary gland and a minimal bulging of the pituitary gland paramedian of the pituitary stalk on the right side. Transsphenoidal inspection revealed a small tumor in the basal and dorsal pituitary gland. Surprisingly, the definite postoperative histopathological diagnosis of the removed tumor was pituicytoma and not pituitary adenoma. Hence, the microadenoma responsible for Cushing’s disease was not yet removed and persistent hypercortisolism necessitated transsphenoidal re-operation. During re-operation, hemihypophysectomy was performed on the right side. The non-tumorous specimen of the adeno-hypophysis showed signs of Crooke’s hyalinization consistent with Cushing’s disease. Undetectable postoperative ACTH- and cortisol levels provided clear evidence that the underlying ACTH-source was successfully removed during re-operation. Coincidence of pituicytoma and pituitary-dependent Cushing’s disease has not previously been reported.

Tuberculum sellae meningioma symptomatic during pregnancy: pathophysiological considerations

SummaryA 31 year old woman in her second pregnancy presented in the 31st (+4) week of gestation with progressive visual impairment of the right eye. Magnetic resonance imaging (MRI) demonstrated a tuberculum sellae meningioma that was displaced upward by a markedly enlarged pituitary gland. Neuro-ophthalmological follow-up examinations showed a progressive decrease of visual acuity and right temporal field loss. Therefore, a caesarean section was performed in the 34th (+8) week. The meningioma was removed three days after childbirth via a right-sided pterional approach. Post-operatively, visual function was completely restored. Immunohistochemical examination showed positive staining for progesterone receptors (PR) in approximately 50% of tumour cells. Enlargement of the pituitary gland during late pregnancy in conjunction with a preexisting tuberculum sellae meningioma is the most likely pathophysiological factor responsible for visual loss. Enlargement of the PR-positive meningioma in the hormonal milieu of pregnancy might have contributed additionally to visual loss.

Reduced intercarotid artery distance in acromegaly: pathophysiologic considerations and implications for transsphenoidal surgery.

BACKGROUND The objective of this study is to evaluate the significance of reduced intercarotid artery distance in the C5 segment in acromegalic patients and the implications for transsphenoidal surgery. METHODS The skull base with the carotid canal was examined with a helical CT scan in 45 patients with acromegaly and 45 age group-matched controls. The distances between the inner walls (IWs) of the carotid sulcus (CS), the outer walls (OWs) of the CS, and the diameter of the ICA at the C5 segment were assessed. Preoperative IGF-1 and growth hormone levels and concomitant diseases were evaluated and correlated with the biometric findings. Statistical analysis was performed with JMP (JMP version 7.0.2, SAS, Cary, USA). RESULTS The mean distance between the IW was 1.64 +/- 0.40 cm in the acromegalic patients and 1.90 +/- 0.26 cm in the control group (P = .0005). The distance between the OW measured 3.01 +/- 0.39 and 2.97 +/- 0.33 cm in the acromegalics and in the control group, respectively (P = .6230). The difference in the diameter of the ICA was statistically significant (P < .0001) between patients and control group. Within the patient group, the distance between the IW of both ICA was significantly smaller in the subgroup with arterial hypertension (P = .0256). CONCLUSION Narrowing of the inner borders of the CS between the right and left side is a statistically significant parameter in acromegaly. Attention should be given to an altered vascular course of the ICAs when planning and performing transsphenoidal microsurgery in acromegalic patients. A preoperative skull base CT may furnish important anatomical information and further reduce the risk of vascular injury.

Cystic lesion of the ventriculus terminalis: proposal for a new clinical classification

The ventriculus terminalis is a small cavity inside the conus medullaris that is formed during the embryonic development. Previous reports regarding cystic lesion of the ventriculus terminalis (CLVT) in adults have detailed a broad and diversified distribution in terms of clinical symptoms, clinical evolution, neurological findings, and treatment. Therefore, nonstandardized management has led to unsatisfactory outcomes. Thus, the authors propose a new classification system in which the clinical presentation is taken into account to standardize the cases and facilitate the proper management of these lesions. Two more cases are described. The literature was reviewed, dividing the patients into 3 groups by clinical presentation as follows: CLVT Type I, patients with nonspecific neurological symptoms or nonspecific complaints; CLVT Type II, presence of focal neurological deficit; and CLVT Type III, presence of sphincter disturbances (bowel or bladder dysfunction). Two patients were classified as CLVT Type I, 3 as CLVT Type II, and 12 as CLVT Type III. In Type I, no improvement was observed in clinical evaluation after surgery, and stable symptoms were achieved with clinical management. In Type II, 2 patients had total improvement and 1 had subtotal improvement after surgery. Finally, in Type III, 92% of the patients improved postoperatively; among these 33% presented with total improvement. Only 1 case in this group was handled conservatively and no improvement was documented. This new classification is useful to group the patients into 3 clinical types to provide guidance as to the best management options. Treatment for the Type I lesion seems to be best conducted conservatively, whereas Types II and III seem to be best handled surgically.

WT1 expression increases with malignancy and indicates unfavourable outcome in astrocytoma

Aims The zinc finger transcription factor WT1 is expressed in astrocytic neoplasms and therefore is a potential target of immunotherapy in brain tumours. Our aim was to further elucidate the role of WT1 as a diagnostic and prognostic marker in neuropathology, particularly as to the differentiation of astrocytoma from oligodendroglioma as well as to the dependency of WT1 expression on clinically relevant parameters. Methods 829 evaluable brain tumour samples were investigated by WT1 immunohistochemistry on full tissue routine slides, consisting of 442 glioblastomas, 303 astrocytomas, 41 oligodendrogliomas and 43 oligoastrocytomas. In addition public WT1 gene expression data of 351 gliomas were analysed. Results Our data show that WT1 expression in diffuse astrocytic tumours increases with WHO tumour grade and is associated with older age, absence of IDH1 mutation but not related to O(6)- methyl guanine methyl transferase (MGMT) promoter methylation status. Univariable, but not multivariable survival analysis indicates that WT1 expression is associated with worse outcome in patients with diffuse astrocytoma but not glioblastoma. Conclusions The significant WT1 expression differences between diffuse astrocytomas, oligoastrocytomas and oligodendrogliomas, which are also present in the Repository for Molecular Brain Neoplasia Data, National Cancer Institute (REMBRANDT, 2005, http://rembrandt.nci.nih.gov) gene database set, provide a rationale for use of WT1 as part of a routine immunohistochemistry panel.

Craniometric changes in patients with acromegaly from a surgical perspective

OBJECT The objective of this study was to evaluate and analyze morphometric and volumetric changes of the skull due to acromegaly in areas relevant for neurosurgical practice, focusing on the surgical implications. METHODS On preoperatively acquired CT scans, cephalometric and volumetric measurements were performed on 45 patients with acromegaly (Group A) and 45 control patients (Group B). The authors determined thickness of the cranial vault, inner and outer diameters of the skull, and the diameter of sphenoidal and maxillary sinus, as well as frontal and maxillary sinus volumetry. The morphometric and volumetric CT data of the patients with acromegaly were compared with the data of a control group and correlated with clinical parameters. RESULTS Cranial vault thickness differed significantly (p < 0.0001) between the 2 groups. A correlation of the vault thickness with preoperative human growth hormone, insulin-like growth factor-I levels, and duration of clinical history in acromegaly could not be established. The outer anterior-posterior skull diameter of Group A (18.47 ± 0.94 cm) differed significantly (p = 0.0146) from Group B (17.98 ± 0.93 cm) and correlated significantly with preoperative human growth hormone (r = 0.3277; p = 0.0299) and insulin-like growth factor-–I serum levels (r = 0.3756; p = 0.0120). Measurements of the anterior-posterior diameter of the sphenoidal sinus differed significantly (p = 0.0074) between patients with acromegaly and controls. Volumetric analysis of the frontal sinus resulted in a statistically significant difference (p = 0.0382) between patients with acromegaly (14.89 ± 10.85 cm3) and controls (10.06 ± 6.93 cm3). CONCLUSIONS Significant craniometric changes and volumetric remodelling of the paranasal sinus occur in acromegaly. The bone alterations are of surgical importance for using the transsphenoidal approach. Detailed preoperative diagnostic examination and planning as well as selection of appropriate instruments are mandatory for safe and successful pituitary adenoma removal in patients with acromegaly.

Intramedullary lesions of the conus medullaris: differential diagnosis and surgical management

The medullary conus represents a distinct entity of the spinal cord regarding its anatomical, clinical and microsurgical features. An overview of the pathologic processes of this region is provided. Epidemiological, clinical and neuroradiological characteristics of neoplastic (glial tumors, non-glial tumors, metastasis, primary melanomas) and non-neoplastic lesions (granulomatous lesions, abscess, parasitic infections, vascular, demyelinating and dysembryogenetic lesions) are discussed. Main MR imaging characteristics used to differentiate neoplastic from non-neoplastic lesions consist in pathological spinal cord expansion, gadolinium-enhancement and tumoural cyst formation. Management strategies differ substantially, depending on the kind of lesion. According to the suspected pathological entity radical resection, biopsy or conservative treatments are reasonable options. Intraoperative electrophysiological monitoring is a fundamental part of the surgical setting.

A new concept in the electrophysiological evaluation of syringomyelia

OBJECT The current neurophysiological assessment of syringomyelia is inadequate. Early-stage syringomyelia is anatomically predisposed to affect decussating spinothalamic fibers that convey pain and sensation primarily. Silent periods have been proven to be a sensitive tool for detecting alterations in this pathway. METHODS Thirty-seven patients with syringomyelia were included in this prospective study. Routine electrophysiological measurements were applied including somatosensory evoked potential (SSEP) and motor evoked potential (MEP) recordings for all extremities. The silent periods were recorded from the pollicis brevis muscle, and electrical stimuli were applied to the ipsilateral digiti II. To establish baseline values, the authors had 28 healthy controls undergo monitoring. Sensitivity and specificity values were statistically evaluated according to the main clinical symptoms (paresis, dissociative syndrome, and pain). RESULTS All control individuals had normal silent periods in voluntarily activated muscle. In syringomyelia patients, the affected limb showed pathological silent periods with all symptoms (sensitivity 30-50%). Pain was the most specific symptom (90%), despite SSEP and MEP values that were within the normal range. CONCLUSIONS Silent period testing is a sensitive neurophysiological technique and an invaluable tool for preoperative assessment of syringomyelia. Silent periods are associated with early dysfunction of thin myelinated spinothalamic tract fibers, even when routine electrophysiological measurements still reveal normal values. Conduction abnormalities that selectively abolish the silent periods can distinguish between hydromyelia (a physiologically dilated central canal) and space-occupying syringomyelia.