Radiation change versus recurrent astrocytoma: diagnostic utility of the proliferation index?

Differentiation of recurrent glioma from radiation damage can be a challenge to neurologists, neurosurgeons, neuroradiologists, and even neuropathologists. We hypothesized that by evaluating sections of recurrent lesions with proliferation markers we might objectively differentiate between radiation damage gliosis and recurrent astrocytoma. We compared the labeling indices of radiation damage and recurrent neoplasm immunohistochemically, using an antibody to MIB-1, a monoclonal antibody to the Ki-67 proliferation marker. Five of the six recurrent neoplasms were gliomas; four these were astrocytic tumors. In most cases, the MIB-1 LI of radiation damage was < 1% and the LI of recurrent neoplasm was > 3%, with pertinent exceptions. We discuss our findings and their possible interpretation.

Death due to a ruptured berry aneurysm in a 3.5-year-old child

Berry aneurysms in childhood are rare and have certain characteristics that distinguish them from their adult counterparts. A case of death caused by a ruptured berry aneurysm in a child is presented, and the topic is reviewed.

Glial tumors in the MNU rat model: induction of pure and mixed gliomas that do not require typical missense mutations of p53

Gliomas were induced in adult male Sprague-Dawley rats by continuous exposure to 100 ppm of N-nitrosmethylurea (MNU) in drinking water. Latency periods for such tumors were 20 and 50 weeks following completion of exposure intervals of 20, 15, and 10 weeks, respectively. Based on histomorphology and the pattern of GFAP immunoreactivity, a large percentage of MNU-induced tumors (>40%) were anaplastic mixed gliomas, having both neoplastic astrocytic and oligodendroglial components. Typical oligodendrogliomas and astrocytomas also occurred less frequently. Unlike the majority of tumors induced by ethylnitrosourea (ENU), MNU yielded glial tumors that did not express synaptophysin. Anaplastic mixed gliomas and glioblastoma multiforme (GBMs) had no missense p53 mutations in the commonly mutated exons 4 through 8 and did not overexpress wild-type p53, suggesting that MNU-induced oncogenesis in rat brain tumors may not require inactivation/alteration of the p53 tumor suppressor gene. The K-ras gene was also analyzed and found to have no activating mutations in brain tumors. This model is suitable for studying genetic events leading to the majority of gliomas that apparently express functional p53.

Correlation of bcl-2, p53, and MIB-1 expression with ependymoma grade and subtype

In this study, we report our results on the proliferative activity of ependymomas as determined by MIB-1 (also known as Ki-67) immunohistochemical analysis, and we compare our results with those obtained by immunolabeling with monoclonal antibodies to p53 and bcl-2 proteins to assess whether expression correlated with ependymoma subtype or tumor grade. The study included 4 myxopapillary ependymomas (Grade I of the World Health Organization [WHO] scale), 10 subependymomas (WHO Grade I), 17 ependymomas (WHO Grade II), 2 papillary ependymomas (WHO grade II), and 4 anaplastic ependymomas (WHO Grade III). The MIB-1 proliferation index was significantly higher in tumors diagnosed as anaplastic ependymoma (P < .001), with a moderate level of correlation (Kendall's tau-b = 0.557, asymptotic standard error = 108). In addition, one ependymoma (WHO Grade II) not considered overtly anaplastic by routine histologic criteria showed a high MIB-1 labeling index, suggesting that the MIB-1 proliferation index might be a more objective indicator of tumor grade. The remaining WHO Grade I and Grade II ependymomas showed low proliferative activity. bcl-2 oncoprotein expression was identified in all of the four myxopapillary and in both papillary ependymomas. An additional observation was the correlation of p53 expression with increasing WHO grade. These data suggest that high MIB-1 and p53 immunolabeling might be objective indicators of high grade in ependymomas that do not otherwise meet routine histologic criteria for high-grade ependymoma. Subsequent clinicopathologic analyses will be important in assessing whether these markers are useful as independent predictors of survival.

Bad news and good news: what the dentist needs to know about transmissible spongiform encephalopathies

Since reports of the "mad cow disease" epidemic in Great Britain erupted in the international press, sensational and intimidating articles about the risk that bovine spongiform encephalopathy and related diseases may pose to humans have appeared. The bad news is that compelling scientific evidence suggests so-called prion disease can and has infected humans, although the overall risk appears to be low. Furthermore, at present, there is no reliable antemortem diagnosis, specific treatment, or vaccine to prevent the disease. The agent thought to be responsible for this unusual class of disease is a rogue protein (called a prion) that, unlike all other agents known to cause infectious disease, contains neither DNA nor RNA. According to a popular hypothesis, normal membrane-associated prion proteins undergo conformational changes that can cause disease. The "bad" prion forms cause holes or a spongy appearance in the brain in all disease variants, hence the generic designation of spongiform encephalopathy. The good news is that risk for exposure to prion disease is exceedingly remote in the dental practice and that current universal infection control procedures are probably sufficient.

Supratentorial giant cell ependymoma: a case report

Ependymomas are neoplasms of the central nervous system that are capable of demonstrating remarkably heterogeneous histologic features. These tumors originate from ependymal cells lining the ventricles, the choroid plexus, the central canal of the spinal cord, and the filum terminale, so they are therefore seen throughout the neuraxis. We describe the case of a 26-year-old man who experienced a 3-week history of right-sided numbness and a 1-week history of worsening bifrontal headache. Computed tomographic scanning and magnetic resonance imaging of his head demonstrated an irregularly enhancing mass involving the left medial frontal lobe, with extension across the corpus callosum and expansion into the body and atrium of the left lateral ventricle. Histologic, immunohistochemical, and electron microscopic findings were consistent with an anaplastic ependymoma. Unique to this neoplasm was the presence of multiple tumor giant cells. The presence of pleomorphic tumor giant cells is a characteristic feature of the subependymal giant cell astrocytoma, and it is also commonly seen in pleomorphic xanthoastrocytoma and glioblastoma multiforme. Bizarre giant cells were recently described in two filum terminale ependymomas. This report presents the first case of a supratentorial giant cell ependymoma with anaplastic features.

Primary epithelioid hemangioendothelioma of the clivus

We describe the clinical, radiologic, and pathologic features of a primary intracranial hemangioendothelioma arising in the clivus in a 38-year-old female, emphasizing the importance of including this rare entity in the differential diagnosis of tumors arising at the base of the skull. To our knowledge, this is the first reported case of a clival hemangioendothelioma. Aside from its unusual location, this case is also notable for its apparent rapid growth and mixed epithelioid-spindle cell morphology. Appropriate neuroimaging studies may offer crucial information, ensuring that this uncommon entity is included in the differential diagnosis of a clival mass.

Hormone receptor immunoreactivity in hemangioblastomas and clear cell renal cell carcinomas

Several primary central nervous system (CNS) neoplasms, including meningiomas, spinal cord ependymomas, and acoustic nerve schwannomas, express hormone receptors. In the present study, we investigated hormone receptor immunoreactivity in hemangioblastomas on the basis of recent reports of these tumors complicating pregnancy. We also evaluated cases of renal cell carcinoma (RCC) metastatic to the CNS, hypothesizing that estrogen receptor (ER), progesterone receptor (PR), or androgen receptor (AR) immunoreactivity might help to distinguish between these histologically similar neoplasms. Immunohistochemical analysis for ERs, PRs, and ARs was performed on paraffin-embedded sections of 27 hemangioblastomas, 12 primary clear cell RCCs, and 5 clear cell RCCs metastatic to the CNS. All of the hemangioblastomas demonstrated PR immunoreactivity, whereas 10 of 12 primary RCCs were negative. In addition, four of the five metastatic RCC were PR positive. All but one primary RCC were ER negative. AR immunoreactivity was seen in three hemangioblastomas, five primary RCCs, and one metastatic RCC. Although hormone receptor immunoreactivity was unable to distinguish between hemangioblastoma and clear cell RCC metastatic to the CNS, the identification of PR immunoreactivity in hemangioblastomas is a new finding that might have adjuvant therapy treatment implications.

Frequency of unilateral and bilateral mesial temporal sclerosis in primary and secondary epilepsy: a forensic autopsy study

Controversy exists regarding the pathogenetic relationship of mesial temporal sclerosis (MTS) to epileptogenesis. Some investigators view hippocampal sclerosis as the primary cause of temporal lobe epilepsy, whereas others interpret the changes to be the result of chronic seizure activity. The present autopsy-based study attempts to clarify the etiologic relationship between mesial temporal sclerosis and epilepsy. To investigate the assumption that bilateral MTS is more likely to be the result of chronic seizure activity associated with a seizure focus outside the hippocampus, two subject groups were identified. The first group comprised 43 patients who had no extrahippocampal pathology and were classified as having primary epilepsy. The second group comprised 35 patients who, had identifiable extrahippocampal pathology and were classified as having secondary epilepsy. Fifteen of the 35 cases of secondary epilepsy also had MTS; seven of these were unilateral and eight were bilateral. Of the 43 cases with primary epilepsy, only one had MTS, and it was unilateral. Significantly more cases of primary epilepsy than secondary epilepsy had no MTS (p < 0.001), suggesting that both unilateral and bilateral forms of MTS occur with greater frequency in subjects with seizure foci outside the hippocampus. These results also suggest that unilaterality of MTS does not exclude an extrahippocampal cause.

Human telomerase RNA expression and MIB-1 (Ki-67) proliferation index distinguish hemangioblastomas from metastatic renal cell carcinomas

Hemangioblastomas are low-grade, capillary rich neoplasms of the cerebellum and spinal cord that can occur sporadically or in the setting of Von Hippel-Lindau syndrome. The present study analyzed the utility of proliferation potential in differentiating hemangioblastoma from RCC metastatic to the central nervous system using a MIB-1 (Ki-67) labeling index and assessment of expression of the RNA component of telomerase. Immunohistochemical analysis for epithelial membrane antigen (EMA) and MIB-1 was performed on paraffin-embedded sections of 27 hemangioblastomas and 5 RCC metastatic to the central nervous system. All but one hemangioblastoma demonstrated low or negative MIB-1 immunoreactivity, while 4 of 5 RCC metastases had moderate or high labeling indices. Telomerase RNA expression was assessed in 10 hemangioblastomas and in all 5 metastatic RCC by in Situ hybridization. All 10 hemangioblastomas demonstrated a lack of expression of telomerase RNA, while all 5 metastatic RCCs showed moderate to strong expression. Our results suggest that the MIB-1 labeling index is useful in differentiating hemangioblastoma from metastatic RCC and assessment of telomerase expression can also provide novel information on the difference in growth potential of these tumors.

Rosenthal fibers and eosinophilic granular bodies in a classic acoustic schwannoma

We describe unique features seen in a case of classic acoustic schwannoma. In the central portion of the tumor, abundant Rosenthal fibers and occasional eosinophilic granular bodies were present. Rosenthal fibers are homogeneous eosinophilic structures commonly seen in central nervous system lesions, such as pilocytic astrocytoma, or in the gliotic tissues adjacent to slowly growing neoplasms and some congenital malformations. Eosinophilic granular bodies are also structural markers of slow-growing, well-differentiated neuroglial neoplasms, such as pleomorphic xanthoastrocytoma, ganglion cell tumors, and pilocytic astrocytoma. To the best of our knowledge, however, these two structures have never before been described in schwannomas.

Expression of telomerase RNA component correlates with the MIB-1 proliferation index in ependymomas

Although there is general agreement that certain morphologic subtypes of ependymoma are benign, the biologic behavior of other ependymal neoplasms is poorly understood and not clearly related to conventional histopathologic criteria. The absence of universally accepted standards has prompted the search for more objective biologic markers. Telomerase is an RNA-containing enzyme associated with immortality in proliferating stem cells and many tumors. We investigated the proliferative activity of 26 ependymomas as determined by MIB-1 immunolabeling and compared the results with the in situ expression of human telomerase RNA (hTR) and WHO tumor grade. The study included 9 WHO grade I ependymomas (6 subependymomas and 3 myxopapillary ependymomas), 13 WHO grade II ependymomas, and 4 anaplastic (WHO grade III) ependymomas. The proliferation index (PI) and telomerase RNA expression were significantly increased in grade III ependymomas (p < 0.0001 for PI and p = 0.0015 for hTR). In these tumors, the PI and hTR expression were highly correlated (p = 0.0001). Of note, a single case designated grade II showed both increased proliferative activity and the highest hTR expression detected in this series of ependymal neoplasms. Our results suggest that the PI and hTR expression may be important biologic markers, independent of other histopathologic criteria of tumor grade. Future studies examining the correlation of MIB-1 cell kinetics and hTR expression with clinical parameters in selected ependymoma subtypes are needed to determine the prognostic relevance of these markers.

Nonneoplastic pineal cysts: a clinicopathologic study of twenty-one cases

Twenty-one cases of nonneoplastic pineal cyst are presented. The patients were 13 women and 8 men, with a median age of 33 years. Sixteen patients were symptomatic. Symptomatic cysts had an average size of 16.5 mm. In most cases, symptoms and signs were related to increased intracranial pressure, cerebrospinal fluid obstruction, neuroophthalmologic dysfunction, brainstem and cerebellar compression, and mental status changes. Uncommon clinical presentations in three cases were related to increased cyst size caused by hemorrhage, sudden death, and postural syncope and loss of consciousness. Imaging studies showed a uniform hypodense or hypointense, nonenhancing pineal mass with occasional peripheral calcification and associated with hydrocephalus, aqueductal compression, tectal deformity, and hemorrhage within the cavity, in decreasing order of frequency. Fourteen patients underwent open cyst resection. Histologically, the intact lesions show a unilocular or multilocular cavity, surrounded by a wall comprised of variable amounts of glial tissue, remnants of pineal gland, and an external fibrous capsule. Follow-up information showed 12 patients alive and well without recurrence between 26 and 144 postoperative months. One patient who underwent stereotactic drainage had a recurrence. One symptomatic patient who did not have surgery died suddenly of causes related to the cyst. The present study supports the role of surgical excision for the treatment of symptomatic pineal cysts to obtain adequate tissue for diagnosis and relief of symptoms. The use of histochemical and immunohistochemical studies may prove useful in the distinction of these lesions with astrocytomas and cystic pineal parenchymal tumors.

Congenital central nervous system tumors

Congenital central nervous system (CNS) tumors are a rare and diverse group of tumors with variable biological behavior depending on location and histology. This review summarizes the published literature and describes the definition, epidemiology, diagnosis and evaluation, and treatment of congenital central nervous system tumors.

Mesenchymal chondrosarcoma: a clinicopathologic and flow cytometric study of 13 cases presenting in the central nervous system

BACKGROUND

Mesenchymal chondrosarcomas arising in the central nervous system are extremely rare. Morphologic features have not been found to correlate reliably with prognosis.

METHODS

Eight intracranial and five intraspinal mesenchymal chondrosarcomas were reviewed with regard to location, treatment, and long term follow-up data. The histopathologic and immunohistochemical results, including Ki-67 nuclear staining frequency, were critically reviewed, and deoxyribonucleic acid content was analyzed by flow cytometry.

RESULTS

Microscopically, all 13 cases were remarkably similar. Immunoreactivity in the small cell component included vimentin in 100% and cytokeratin and glial fibrillary acidic protein in 25% of cases. S-100 immunoreactivity was noted in the cartilaginous component of 100% of cases, and in rare cells in the small cell component along the interface. Flow cytometry of the eight tumors studied revealed a diploid pattern in six, aneuploidy in two, and a wide range of S-phase fractions (0-36.5%).

CONCLUSIONS

Review of the literature and the findings of the current series indicates that mesenchymal chondrosarcomas presenting in the brain and spinal cord pursue a progressive course that correlates most reliably with extent of surgical resection. This limited retrospective study also suggests that survival may be shorter for those patients with a high S-phase fraction and a high Ki-67 staining frequency.

Infrequency of p53 gene mutations in ependymomas

Ependymomas, which comprise 5% of central nervous system tumors, have not been extensively characterized genetically. The p53 tumor suppressor gene is frequently mutated in human cancer, and is important in the pathogenesis of other central nervous system (CNS) tumors. Chromosomal DNA corresponding to the p53 tumor suppressor gene was amplified by the polymerase chain reaction (PCR) from 31 archival ependymoma specimens. DNA was screened for the presence of p53 mutations by single strand conformational polymorphism (SSCP) analysis; samples with altered mobility were further tested for the presence of mutation by direct DNA sequence analysis. Of the 31 ependymomas tested, one contained a detectable DNA sequence change in the p53 gene. Sequencing revealed a silent mutation in exon 6, at codon 213, which represents a known p53 sequence polymorphism. These finding suggest that in contrast to many other human cancers, p53 mutation is not important in the pathogenesis or progression of ependymomas.

Mesenchymal chondrosarcoma of the cauda equina

Primary central nervous system mesenchymal chondrosarcomas are extremely rare tumors composed of primitive mesenchymal cells punctuated by islands of cartilage in various stages of differentiation. Although there are isolated reports of tumors arising in the spinal dura, to our knowledge extraskeletal mesenchymal chondrosarcoma localized to the cauda equina has not been reported in the literature. We present an unusual case of a mesenchymal chondrosarcoma involving the nerve roots of the cauda equina. The clinical, pathological and neuroimaging features are reviewed and discussed.

Tumors of pineal parenchymal cells: a correlation of histological features, including nucleolar organizer regions, with survival in 35 cases

We studied 35 parenchymal neoplasms arising in the pineal gland, including 11 pineoblastomas, 21 pineocytomas, and three mixed pineocytoma-pineoblastomas. Pineoblastomas were most commonly found in children (mean age, 12.6 years). The median postsurgical length of survival for seven patients, including five with remote metastases, with fatal outcome was 24 months. The 21 pineocytomas were found in older individuals (mean age, 26.8 years). Four patients with pineocytoma died; two before surgery and two in the immediate postoperative period. The remaining 17 patients survived for intervals between 6 and 118 months after surgery. Two mixed pineocytoma-pineoblastomas were found in infants who died a few months after biopsy, whereas a third patient, an adult, was alive at 46 months after excision and irradiation. Both pineoblastoma and pineocytoma exhibited variable immunoreactivity to neurofilament proteins, synaptophysin, glial fibrillary acidic protein, S-100 protein, retinal-S antigen, and rhodopsin; the highest percentages of positive cells stained with synaptophysin. Three pineocytomas exhibited ganglionic differentiation and two of them also showed a glial component. Prognosis could not be correlated with the degree of divergent differentiation. Comparison of silver-stained nucleolar organizer region (AgNOR) counts between pineoblastomas and pineocytomas suggests that the former are more actively proliferative than the latter, with mixed pineocytoma-pineoblastoma showing intermediate activity. There was no correlation between AgNOR score and prognosis within the three tumor groups.

Optic pathway glioma infiltrating into somatostatinergic pathways in a young boy with gigantism. Case report

The authors report gigantism in a 16-month-old boy with an extensive optic pathway glioma infiltrating into somatostatinergic pathways, as revealed by magnetic resonance imaging and immunocytochemical studies. Stereotactic biopsies of areas showing hyperintense signal abnormalities on T2-weighted images in and adjacent to the involved visual pathways provided rarely obtained histological correlation of such areas. The patient received chemotherapy, which resulted in reduction of size and signal intensity of the tumor and stabilization of vision and growth velocity.

Cerebellopontine angle masses: radiologic-pathologic correlation

The cerebellopontine angle cistern is a cerebrospinal fluid-filled space bound by the pons, cerebellum, and petrous temporal bone. Masses in this region are readily identified on cross-sectional images. Differential diagnosis of masses in this region can be simplified by using an algorithmic approach that combines morphologic and enhancement characteristics with established demographic data. Schwannomas are enhancing, round masses, most commonly arising from the vestibular nerve near the porus acusticus and associated with enlargement of the internal auditory canal. Meningiomas are enhancing, oval or hemispheric lesions with a broad attachment to the tentorium or petrous dura mater. Congenital epidermoid inclusion cysts are nonenhancing masses that have undulating margins, molding their shape to conform to the adjacent structures. Aneurysms without significant internal thrombus have prominent flow voids on magnetic resonance images.

Problems in the nosology of desmoplastic tumors of childhood

Several types of central nervous system tumors primarily consisting of a combination of astrocytes and fibrocollagen and occurring most commonly in infancy have been separately introduced as new diagnostic entities. The names applied to these tumors have included 'gliofibroma', 'desmoplastic cerebral astrocytoma', and 'desmoplastic infantile ganglioglioma', a group containing ganglion cells as well as the astrocytes and mesenchymal tissue. We studied a gliofibroma arising in the fourth ventricle of a 6-month-old infant and three examples of desmoplastic cerebral astrocytoma in infants utilizing routine histological and immunocytochemical methods, and at the ultrastructural level in two tumors. In view that the desmoplastic cerebral astrocytomas contain poorly differentiated neuroepithelial cells and rarely, a ganglion cell, we suggest that gliofibroma and desmoplastic astrocytoma are basically the same entity and that the desmoplastic infantile ganglioglioma is a variant containing primitive or mature ganglion cells.

Pineal region masses: differential diagnosis

Most pineal region masses are malignant germ cell neoplasms that occur in young male patients. The most common is a germinoma, which is a homogeneous mass with signal intensity and attenuation similar to those of gray matter; the mass engulfs a densely calcified pineal gland. Teratomas are multilocular heterogeneous masses containing lipid areas. Other types of pineal region masses include choriocarcinoma, endodermal sinus tumor, and embryonal carcinoma. Pineal parenchymal neoplasms are usually either pineocytomas or pineoblastomas, which may "explode" preexisting pineal calcifications. Unlike the germinomas, they have no sexual predilection and may be seen in patients who are 20 years of age or older. Although the correct histologic diagnosis may be suggested with a careful evaluation of the morphologic features, attenuation, and signal intensity characteristics, very few of these tumors have a truly pathognomonic imaging pattern. Thus, histologic verification is necessary for most pineal region masses that appear to be neoplastic.