INTRAOSSEOUS SPINAL GLOMUS TUMORS

OBJECTIVE

Glomus tumors are rare lesions that can arise intraosseously along the entire spinal axis. Only four cases have been reported, usually manifesting with severe back pain and involving the midthoracic spine or sacrum. The current report describes the largest such lesion reported in the literature to date and summarizes the clinical and pathological characteristics of these rare tumors.

METHODS

A single, recent case arising from the lumbar vertebra of L3 is described, and the literature of intraosseous spinal glomus tumors is reviewed.

RESULTS

The lesion described arose in a 44-year-old man with a 1-year history of neurological symptoms and a large dumbbell-shaped lesion involving the lumbar vertebra, which extended through the neural foramen at L3. The lesion was resected using a two-stage approach. Severe intraoperative hemorrhage necessitated emergent angiographic embolization. Histopathological examination confirmed the presence of a glomus tumor arising from the smooth muscle cells of the glomus body.

CONCLUSION

These rare lesions may extend into the epidural space and through the neural foramina and abdominal compartments; over time, they grow very large. Preoperative embolization may be indicated for large tumors suspected to be glomus tumors.

Are cavernous sinus hemangiomas and cavernous malformations different entities?

Cavernous hemangiomas that occur within the cavernous sinus (CS) are different from cerebral cavernous malformations (CMs) clinically, on imaging studies, and in their response to treatment. Moreover, CMs are true vascular malformations, whereas hemangiomas are benign vascular tumors. Because of these differences, the authors suggest that these two entities be analyzed and grouped separately. Unfortunately, despite these differences, much confusion exists in the literature as to the nature, behavior, and classification of these two distinct lesions. This confusion is exacerbated by subtle histological differences and the inconsistent use of nomenclature. The authors use the term "cavernous malformation" to refer to intraaxial lesions only; they prefer to use the term "cavernous sinus hemangioma" to refer to extraaxial, intradural hemangiomas of the CS.

Electrophysiological properties of human hypothalamic hamartomas

The hypothalamic hamartoma (HH) is a rare developmental malformation often characterized by gelastic seizures, which are usually refractory to medical therapy. The mechanisms of epileptogenesis operative in this subcortical lesion are unknown. In this study, we used standard patch-clamp electrophysiological techniques combined with histochemical approaches to study individual cells from human HH tissue immediately after surgical resection. More than 90% of dissociated HH cells were small (6-9 microm soma) and exhibited immunoreactivity to the neuronal marker NeuN, and to glutamic acid decarboxylase, but not to glial fibrillary acidic protein. Under current-clamp, whole-cell recordings in single dissociated cells or in intact HH slices demonstrated typical neuronal responses to depolarizing and hyperpolarizing current injection. In some cases, HH cells exhibited a "sag-like" membrane potential change during membrane hyperpolarization. Interestingly, most HH cells exhibited robust, spontaneous "pacemaker-like" action potential firing. Under voltage-clamp, dissociated HH cells exhibited functional tetrodotoxin (TTX)-sensitive Na(+) and tetraethylammonium-sensitive K(+) currents. Both GABA and glutamate evoked whole-cell currents, with GABA exhibiting a peak current amplitude 10-fold greater than glutamate. These findings suggest that human HH tissues, associated with gelastic seizures, contained predominantly small GABAergic inhibitory neurons that exhibited intrinsic "pacemaker-like" behavior.

Anterior communicating artery aneurysm following radiation therapy for optic glioma: report of a case and review of the literature

A 42-year-old female presented with subarachnoid hemorrhage (SAH), presumably from a radiation-induced anterior communicating artery aneurysm. Six years earlier, she had undergone radiation treatment for an optic glioma that was diagnosed based on imaging criteria. The aneurysm was successfully clipped, and the optic glioma was biopsied to verify the diagnosis histologically. Radiation-induced cerebral aneurysms often manifest with a fatal SAH. These aneurysms typically develop in the field of radiation and are diagnosed a mean of 8.52 years after radiation. Rarely, the aneurysm sac thromboses spontaneously. Clipping or coiling of the aneurysm can be an effective treatment.

Is gross-total resection sufficient treatment for posterior fossa ependymomas?

Object. The goals of this study were to analyze outcomes in patients with posterior fossa ependymomas, determine whether gross-total resection (GTR) alone is appropriate treatment, and evaluate the role of radiation therapy.

Methods. All patients with newly diagnosed intracranial ependymomas treated at Barrow Neurological Institute between 1983 and 2002 were identified. Those with supratentorial primary lesions, subependymomas, or neuraxis dissemination were excluded. Forty-five patients met the criteria for the study. Gross-total resection was accomplished in 32 patients (71%) and subtotal resection (STR) in 13 (29%). Radiation therapy was given to 25 patients: 13 following GTR and 12 after STR. The radiation fields were craniospinal followed by a posterior fossa boost in six patients and posterior fossa or local only in the remaining patients.

With a median follow-up period of 66 months, the median duration of local control was 73.5 months with GTR alone, but has not yet been reached for patients with both GTR and radiotherapy (p = 0.020). The median duration of local control following STR and radiotherapy was 79.6 months. The 10-year actuarial local control rate was 100% for patients who underwent GTR and radiotherapy, 50% for those who underwent GTR alone, and 36% for those who underwent both STR and radiotherapy, representing significant differences between the GTR-plus-radiotherapy and GTR-alone cohorts (p = 0.018), and between the GTR-plus-radiotherapy and the STR-plus-radiotherapy group (p = 0.003). There was no significant difference in the 10-year actuarial local control rate between the GTR-alone and STR-plus-radiotherapy cohorts (p = 0.370). The 10-year overall survival was numerically superior in patients who underwent both GTR and radiotherapy: 83% compared with 67% in those who underwent GTR alone and 43% in those who underwent both STR and radiotherapy. These differences did not achieve statistical significance. Univariate analyses revealed that radiotherapy, tumor grade, and extent of resection were significant predictors of local control.

Conclusions. Gross-total resection should be the intent of surgery when it can be accomplished with an acceptable degree of morbidity. Even after GTR has been confirmed with postoperative imaging, however, adjuvant radiotherapy significantly improves local control. The authors currently recommend the use of postoperative radiotherapy, regardless of whether the resection is gross total or subtotal.

Diagnosis and Management of Pineocytomas

OBJECTIVE:

Pineocytomas are associated with the most favorable prognosis of all pineal tumors. However, a subset of pineocytomas may have a predilection for recurrence and therefore behave aggressively.

PATIENTS AND METHODS:

Records of nine patients (five men, four women; mean age, 44 yr; range, 24–63 yr) with histologically diagnosed pineocytomas consecutively treated between 1990 and 2003 were reviewed retrospectively to identify factors predictive of aggressiveness. Eight patients presented with hydrocephalus and four with tectal compression. Three patients underwent gross total resection, and six underwent subtotal resection or biopsy.

RESULTS:

Three local recurrences necessitated reoperation. One recurrence involved the obex of the fourth ventricle. The mean time to recurrence was 3.5 years (range, 1–7 yr). There was no correlation between histological features and tumor recurrence. Patients undergoing radiosurgery showed stable or attenuated local disease (mean follow-up, 19.3 mo; range, 6–36 mo). Mean radiographic follow-up was 34 months (range, 6 mo to 10 yr). Mean clinical follow-up was 36 months (range, 1 mo to 10 yr).

CONCLUSION:

A subset of pineocytomas demonstrates the potential for symptomatic recurrence. We advocate an attempt at gross total tumor resection for all symptomatic patients with tectal plate compression, reserving radiosurgery for small, subtotally resected, or recurrent lesions. Patients must be followed closely for recurrence. Radiosurgery seems to be beneficial for local tumor control. Further investigation is needed to identify histological markers for pineocytomas that behave aggressively.

Consistency of Primary Brain Tumor Diagnoses and Codes in Cancer Surveillance Systems

High-quality cancer registry data are essential for assessing trends in incidence rates. This study evaluated the consistency of brain tumor surveillance data using a random sample of cases from the Connecticut Tumor Registry. Three neuropathologists independently and blindly reviewed tumor slides from 204 cases and a nosologist blindly reviewed and assigned International Classification of Diseases for Oncology (ICD-O) codes to 326 cases. For the pathology review, absolute concordance was as high as 81% for all primary brain tumors. Absolute concordance rates were high for nerve sheath (89%), meningioma (95%), and pituitary (95%) tumors. Rates were much lower for malignant tumors. ICD-O coding of malignant brain tumors is of relatively high quality with the exception of mixed gliomas and unspecified tumors. A high level of consistency for nonmalignant brain tumor diagnoses suggests that rates for these tumors, when actively reported to a surveillance system, can be of high quality.

Ectopic intracavernous sinus adrenocorticotropic hormone-secreting microadenoma: could this be a common cause of failed transsphenoidal surgery in Cushing disease? Case report

Despite diagnostic advances, it remains difficult to identify intrasellar and ectopic parasellar adrenocorticotropic hormone (ACTH)-secreting microadenomas. The authors present the case of a 61-year-old woman with Cushing disease in whom a significant central-to-peripheral and lateralized right-sided ACTH gradient was demonstrated on inferior petrosal sinus sampling; no discernible abnormality was seen on magnetic resonance imaging. She underwent transnasal transsphenoidal surgery. No tumor was found on sellar exploration and a total hypophysectomy was performed, yet her hypercortisolemia persisted. The patient died of cardiac events 17 days postsurgery. Autopsy revealed an isolated, right-sided, intracavernous ACTH-secreting adenoma with no intrasellar communication. This case represents the first failed transsphenoidal surgery for Cushing disease in which there is postmortem confirmation of a suspected intracavernous sinus lesion. It supports the hypothesis that Cushing disease associated with nondiagnostic imaging studies, a strong ACTH gradient on venography, and negative findings on sellar exploration may be caused by an ectopic intracavernous ACTH-secreting adenoma. There are no premortem means of confirming the presence of such lesions, but these tumors could underlie similar cases of failed surgery. Radiation therapy targeting the sella turcica and both cavernous sinuses, possibly supplemented with medical treatment, is suggested for similar patients in whom transsphenoidal hypophysectomy has failed. Adrenalectomy may also be appropriate if a rapid reduction in ACTH is necessary.

Pena-Shokier phenotype: case presentation and review

Pena-Shokier phenotype is an early lethal disorder involving multiple joint contractures, facial anomalies, and pulmonary hypoplasia. Alternative terms for this syndrome used in the literature include fetal hypokinesia syndrome, lethal congenital contracture syndrome, and Pena-Shokier syndrome type I. The etiology for the early cases was attributed to neuromuscular disease, with deformations owing to weakness or paralysis of the motor unit. An abnormality of spinal cord motoneurons has been postulated in some cases. Pena-Shokier phenotype can also result from blockade of the neuromuscular junction, as shown by recent observations with women expressing antibodies against the fetal acetylcholine receptor. It has been shown that the Pena-Shokier phenotype may result from intrauterine cerebral dysfunction as well, including acquired brain insults and congenital brain malformations. The ultimate prognosis for children with this disorder is dependent on the underlying etiology and the severity of pulmonary disease. The authors report a fatal case of Pena-Shokier phenotype with congenital polymicrogyria. To our knowledge, the case presented is the first reported Pena-Shokier phenotype associated with this type of brain malformation.

Pathology of cerebral vascular malformations

The gross and microscopic features of cerebral arteriovenous malformations, cavernous malformations, capillary telangiectases, and venous malformations are compared and contrasted. The pathogenesis of these lesions and possible interrelationships suggested by transitional lesions are also reviewed.

Nuclear accumulation of fibroblast growth factor receptors in human glial cells--association with cell proliferation

In this study we describe the presence of high affinity FGF-2 binding sites in the nuclei of U251MG glioma cells (K(d)=7 pM). Immunoprecipitation of total cell extracts with FGF receptor (FGFR) 1-4 antibodies showed that U251MG glioma cells express only FGFR1. [125I]FGF-2 cross linking to nuclear extracts followed by FGFR1 immunoprecipitation showed that FGFR1 may account for the nuclear FGF-2 binding sites. Western blot analysis demonstrated the presence of 103, 118 kDa and small amounts of 145 kDa FGFR1 isoforms in the nuclei of glioma cells. All isoforms contain both the C- and N-terminal domains. Nuclear FGFR1 retains kinase activity. Immunocytochemistry using confocal microscopy showed specific FGFR1 immunoreactivity within the nuclear interior. In continuously proliferating glioma cells, nuclear FGFR1 is constitutively expressed, independent of cell density. In contrast, in nontransformed human astrocytes, nuclear FGFR1 levels fluctuate with the proliferative state of the cell. In quiescent, confluent astrocytes nuclear FGFR1 protein was depleted. An accumulation of nuclear FGFR1 was observed following the transition to a subconfluent, proliferating state. Transfection of a pcDNA3.1-FGFR1 expression vector into glioma cells that do not express FGFR1 resulted in the nuclear accumulation of FGFR1, increased cell proliferation, and stimulated transition from the G0/G1 to the S-phase of the cell cycle. The increased proliferative rate was resistant to inhibition by the cell-impermeable FGF binding antagonist, myoinositol hexakis [dihydrogen phosphate]. Our results suggest that the constitutive nuclear presence of FGFR1 contributes to the increased proliferation of glioma cells while the transient nuclear accumulation of FGFR1 in normal astrocytes may play a role in the transition to a reactive state.

Nuclear accumulation of FGF-2 is associated with proliferation of human astrocytes and glioma cells

FGF-2 has been implicated in the neoplastic transformation of glioma cells and in the transition of normal quiescent astrocytes to a proliferating, reactive state. In the present study we have observed that in human glial cells, levels and subcellular localization of FGF-2 are different in quiescent and proliferating cells. FGF-2 was detected in the cytoplasm of non-reactive astrocytes in human brain sections. In contrast FGF-2 was located within the cytoplasm and nuclei of reactive astrocytes in gliotic brain tissue and in neoplastic cells of glioma tumors. In vitro, FGF-2 was found predominantly in the nucleus of subconfluent proliferating astrocytes, but was detected only in the cytoplasm of density arrested quiescent astrocytes. Our results suggest that reduced cell contact stimulates nuclear accumulation of FGF-2, accompanying mitotic activation of reactive human astrocytes. FGF-2 was constitutively localized to the nucleus of continuously proliferating glioma cells independent of cell density. A role for intracellular FGF-2 was further suggested by the observation that glioma cells that are not stimulated to proliferate by extracellular FGF-2 proliferated faster when transfected with FGF-2 expressing vectors. This increased proliferation correlated with nuclear accumulation of FGF-2. Cell proliferation was attenuated by 5'-deoxy-5'-methylthioadenosine, a FGF-2 receptor tyrosine kinase inhibitor that acts within the cell, but was unaffected by myo-inositol hexakis [dihydrogen phosphate] that disrupts FGF-2 binding to plasma membrane receptors. Our results indicate that FGF-2 serves as a nuclear regulator of proliferation in astrocytic cells. In glioma cells, the constitutive presence of FGF-2 in the nucleus may promote proliferation that is insensitive to cell contact inhibition.

Retrospective study of the correlation between the DNA repair protein alkyltransferase and survival of brain tumor patients treated with carmustine

We tested the hypothesis that the level of the DNA repair protein O6-alkylguanine-DNA alkyltransferase in brain tumors was correlated with resistance to carmustine (BCNU) chemotherapy. Alkyltransferase levels in individual cells in sections from 167 primary brain tumors treated with BCNU were quantitated with an immunofluorescence assay using monoclonal antibodies against human alkyltransferase. Patients with high levels of alkyltransferase had shorter time to treatment failure (P = 0.05) and death (P = 0.004) and a death rate 1.7 times greater than patients with low alkyltransferase levels. Furthermore, the size of the subpopulation of cells with high levels of alkyltransferase was correlated directly with drug resistance. For all tumors the variables most closely correlated with survival, in order of importance, were age, tumor grade, and alkyltransferase levels. For glioblastoma multiforme, survival was more strongly correlated with alkyltransferase levels than with age. These results should encourage prospective studies to evaluate alkyltransferase levels as a method, for identifying brain tumor patients with the best likelihood of response to BCNU chemotherapy.

Comparative anatomy of the baboon and the human cervical spine

STUDY DESIGN

The anatomy of baboon and human cervical spines were compared by measuring adult, cadaveric specimens.

OBJECTIVE

The objective of the study was to compare human and baboon cervical motion segments to determine whether the baboon provides a suitable model for spinal research.

SUMMARY OF BACKGROUND DATA

Several studies have examined the quantitative anatomy of the human cervical bones and ligaments. Several animal species have been used for cervical spine research; however, no studies have validated whether the animal models resemble the human cervical spine closely enough to provide generalizable data.

METHODS

Multiple morphologic parameters were measured directly from nine baboon and six human adult cadaveric cervical spine specimens. The bone structure and geometry of each of the seven cervical vertebrae were analyzed; the structure and histology of the ligaments were measured; and histomorphometry of the vertebrae was performed.

RESULTS

The architectural composition and geometry of individual cervical vertebrae of baboons and humans were similar at each level. The proportional relationship of bone and ligament structures in the two species was almost identical. There were, however, several differences: 1) The baboon spine was about half the size of the human spine; 2) its vertebral arteries were encased fully within the C1 lateral mass; 3) its uncovertebral joints were more prominent; 4) its vertebral endplates were more concave; 5) its pedicles were thinner; 6) its transverse processes were longer; and 7) its spinous processes were horizontal and nonbifid.

CONCLUSIONS

The geometry and anatomy of the baboon cervical spine closely resemble that of the human cervical spine. It therefore provides an excellent model for in vivo and in vitro research.

Morphology and kinematics of the baboon upper cervical spine. A model of the atlantoaxial complex

STUDY DESIGN

Quantitative and qualitative analyses were performed to compare the anatomy and biomechanics of baboon and human upper cervical spines.

OBJECTIVES

This study examined the baboon as a potential model for in vivo and in vitro atlantoaxial research.

SUMMARY OF BACKGROUND DATA

A variety of animal models have been used for spine research; however, no species have been used for C1-C2 research. Most species have remarkably different C1-C2 morphology compared with that of humans.

METHODS

Twenty baboon and seven human normal adult cadaveric upper cervical spines were studied morphologically. C1-C2 motion segments were analyzed biomechanically using a flexibility method of testing with physiologic range, nondestructive loading. Motion and load-deformation relationships were studied during flexion, extension, bilateral lateral bending, and bilateral axial rotation.

RESULTS

The bones and ligaments of the baboon and human upper cervical vertebrae have similarly proportioned structures, identical individual components, and similar geometric configurations. The average size of the baboon vertebrae was 50% to 60% of the human specimens. There were several minor anatomical differences. Baboons had more horizontal C2-C3 facet joints and more vertical C1-C2 articular surfaces; the vertebral arteries were encased in a continuous bony canal in C1. Biomechanical testing demonstrated that baboons and humans had similarly proportioned neutral zones and elastic zones. Compared with humans, baboons had a 2 degrees to 9 degrees wider range of motion in all directions.

CONCLUSIONS

The baboon and human upper cervical anatomy and biomechanics are similar. The baboon may be useful to study atlantoaxial biomechanics and pathology.

MR characteristics of meningioma subtypes at 1.5 tesla

Analysis of MR signal characteristics and histopathologic findings confirms the strong correlation between meningioma subtype and observed signal intensity (SI) changes in 24 patients imaged at 1.5 T. On T2-weighted images, 90% of fibroblastic and transitional tumors were hypointense relative to cerebral cortex (SI intermediate greater than SI T2-weighted images); conversely, 66% of meningothelial subtypes displayed persistent hyperintensity (SI intermediate less than or equal to SI T2-weighted images), and the remaining one-third demonstrated mixed high-signal changes. Subtype specific differences in collagen distribution and cellularity, i.e., tumor geometry, appeared to account for these signal trends. Based solely on SI characteristics, correct histologic subgrouping of tumors as either fibroblastic/transitional or meningothelial/angioblastic was possible in 80% (19 of 24) of patients. Utilization of adjunctive imaging features (i.e., mass effect, peritumoral edema, intratumoral cyst formation) in conjunction with signal changes permitted a correct histologic pattern in 96% (23 of 24) of patients.

Choroid plexus carcinoma in siblings: a study by light and electron microscopy with Ki-67 immunocytochemistry

Choroid plexus carcinomas in siblings aged 11 months and 10 years were examined by light microscopy and immunocytochemistry. One case was studied by electron microscopy. Choroid plexus carcinoma is rare, with approximately 24 reported cases in children. Predicting the behavior of choroid plexus tumors from the histology can be difficult. Neither mitoses nor necrosis were seen in one case, but evaluation of proliferation using Ki-67 monoclonal antibody showed 9% of the cells to be in proliferative phases of the cell cycle, a high value for a glial-derived neoplasm. Ki-67 activity may be a more sensitive measure of proliferation in malignant choroid plexus tumors than the presence of mitoses and necrosis, and additional studies may establish its role in distinguishing between choroid plexus carcinoma and papilloma when histologic classification is equivocal. Both tumors were immunoreactive for keratin, which confirmed previous studies. Both were nonreactive for glial fibrillary acidic protein, S-100, and carcinoembryonic antigen (CEA), unlike a previous study which reported that choroid plexus carcinoma, compared to papilloma, was uniquely S-100-negative and CEA-positive. Choroid plexus carcinoma in siblings has not been reported. Chance occurrence in siblings is extremely unlikely; thus a genetic basis for the neoplasms is likely, although environmental influences cannot be excluded.