Cryo-EM Structure of AAV2 Rep68 bound to integration site AAVS1: Insights into the mechanism of DNA melting

The Rep68 protein from Adeno-Associated Virus (AAV) is a multifunctional SF3 helicase that performs most of the DNA transactions required for the viral life cycle. During AAV DNA replication, Rep68 assembles at the origin and catalyzes the DNA melting and nicking reactions during the hairpin rolling replication process to complete the second-strand synthesis of the AAV genome. Here, we report the Cryo-EM structures of Rep68 bound to double-stranded DNA (dsDNA) containing the sequence of the AAVS1 integration site in different nucleotide-bound states. In the apo state, Rep68 forms a heptameric complex around DNA, with three Origin Binding Domains (OBDs) bound to the Rep Binding Site (RBS) sequence and three other OBDs forming transient dimers with them. The AAA+ domains form an open ring with no interactions between subunits and with DNA. We hypothesize the heptameric quaternary structure is necessary to load onto dsDNA. In the ATPγS-bound state, a subset of three subunits binds the nucleotide, undergoing a large conformational change, inducing the formation of intersubunit interactions interaction and interaction with three consecutive DNA phosphate groups. Moreover, the induced conformational change positions three phenylalanine residues to come in close contact with the DNA backbone, producing a distortion in the DNA. We propose that the phenylalanine residues can potentially act as a hydrophobic wedge in the DNA melting process.

P14.32 Patterns of invasion in Glioblastoma have unique radiological features, varied response to radiotherapy and long term outcomes

BACKGROUND

To assess the correlation of the three patterns of invasion of Glioblastoma (GB) with the respective MRI features, response to radiotherapy and disease free survival

MATERIAL AND METHODS

Histopathology of 62 patients with Glioblastoma who had undergone maximal safe resection (MSR)/ stereotactic biopsy (STB) & referred for adjuvant therapy was reviewed to assess the pattern of invasion. Three patterns were observed- single cell infiltration (pattern 1), perineuronal satellitosis (pattern 2) and vessel cooption (or perivascular spread, pattern 3), majority also had diffuse infiltration pattern in the background. The pre and post operative MRI scans were utilized for RT planning of 3DCRT/ IMRT/ VMAT, the modality decided by the treating oncologist. RT volumes were as per ESTRO-ACROP guidelines. Duration of radiotherapy- the Stupp regimen or a short course of hypofractionated radiotherapy (HFRT) (35Gy/10Fr- planned gap- completion of total dose) was based on the extent of resection (EOR) and KPS at the time of RT. Correlation of the pattern of invasion, MRI characteristics of each on the response to radiotherapy as assessed by RANO criteria and survival was analysed with the help of SPSS V21.

RESULTS

MRI findings after stratification of 62 patients, median age 43 years(18–70), M:F::42:20) into type 1:17, type 2:21 and type 3:24- patterns of invasion, were cortical tumours (subtle enhancement) close to SVZ, solid (+/- cystic) lesion in the eloquent cortex or large mass effect crossing the barriers respectively. OS of entire cohort at 1 year was 75%, with significant differences among groups (82% vs. 85% vs. 50%). Among pattern 1, those patients with IDH mutant (20%) & mean dose to C/L SVZ of 30Gy or more had longer DFS at 1 year (89% Vs. 38% & 85% vs. 0%, p<0.05). In pattern 2, EOR (gross total or near total resection Vs. only STB) showed a better DFS at 1 year (90% vs. 40%, p=0.095). In patients with pattern 3, 40% had post op KPS of <80 and 20% of them underwent HFRT who showed higher CR/PR rates compared to the conventional RT. HFRT in low KPS with m-MGMT showed higher local control at 6 months (100% Vs. 66%, p= 0.02).

CONCLUSION

Glioblastoma has three patterns of invasion with unique MRI features and aggressiveness for each. Identification of this may guide choice of adjuvant therapy, patterns of failure and therapy resistance

P14.94 Mitochondrial DNA copy number in new onset and recurrent glioblastoma and its effect on radiation resistance and patient survival

BACKGROUND

Recent evidence shows that mitochondrial DNA (mtDNA) content is responsible for radiation resistance in various cancers, but not evaluated in glioblastoma(GBM).Hence,we studied the role of mtDNA content in GBM pathogenesis and treatment response.

MATERIAL AND METHODS

Archived FFPE tissues of newly diagnosed GBM(n=130), recurrent GBM (n=32 pairs) and non-neoplastic control brain(n=30) with available clinical details were utilized for the study. Immunohistochemistry, Sanger’s sequencing, methylation specific PCR and fluorescent in-situ hybridization were used to study IDH, ATRX and TERT promoter mutations, MGMT promoter methylation and EGFR amplification. mtDNA content was analyzed using quantitative real time PCR (relative quantification) and was calculated using the formula 2- ΔΔCTx100. Malignant glioma cell lines U87 and LN229 were used to study the difference in mtDNA content following radiation exposure.LN229 cell line was subjected to mtDNA depletion by incubation with ethidium bromide for 4 days.The parent and mtDNA depleted LN229 cell lines were then assessed for sensitivity to radiation and Temozolomide(TMZ) therapy using MTT assay.

RESULTS

mtDNA content was lower than control brain tissue(mean mtDNA content 19.6) in all cases studied,with significantly lower content in older patients(p=0.04).Lower mean mtDNA content was seen in IDH wild type, MGMT unmethylated and EGFR amplified tumors when compared to their counterparts(p=1.06).Survival analysis using Cox regression showed that lower mtDNA copy number is associated with higher risk and hence poorer prognosis(p=0.047).Paired tumor analysis was performed in 32 patients with recurrence of whom only 19 had received radiation therapy (RT).The mean mtDNA content was higher at recurrence as compared to the primary tumor in those who received RT(mean at diagnosis 20.1; mean at recurrence 49.3, p=0.02) while no significant difference was observed in those who did not receive RT. U87 and LN229 cell lines exposed to radiation (0, 2, 4 and 6Gy) showed an increase of 8% and 25% in mtDNA content, respectively, after 6Gy radiation exposure.LN229 parent cells showed a radiation dose dependent decline in cell viability(86% at 2Gy, 68% at 4Gy and 50% at 6Gy).The mtDNA depleted LN229 cells were 100% viable at 0, 2 and 4 Gy and 82% viable at 6Gy.The IC50 of TMZ in parent LN229 cells was 69.3 µM while in the mtDNA depleted cells,it was 100.8 µM. Conclusion:Our study shows that lower mtDNA content is associated with poorer survival in GBM.RT increased the mtDNA content in both patient samples and malignant glioma cell lines.mtDNA depleted LN229 lines are more radio-chemo resistant than parent LN229 lines,thus showing that lower mtDNA content leads to treatment resistance.Hence,we establish the significant role of mtDNA content in the pathogenesis and treatment resistance of GBM.

Stereotactic biopsy of brainstem lesions: Techniques, efficacy, safety, and disease variation between adults and children: A single institutional series and review

BACKGROUND

Stereotactic biopsy of brainstem lesions have been performed with varying indications, with most of the literature reporting on children.

MATERIALS AND METHODS

The present study retrospectively analyzed all cases that underwent stereotactic biopsy for brainstem lesion in both adult and pediatric population between 1994 and 2009 in a single tertiary neurosurgical center. The clinical and radiological features, technique of the procedure, morbidity, diagnostic accuracy, spectrum of diagnosis, and variations in adult and pediatric population were analyzed.

RESULTS

Eighty-two patients were included in the study. Computed tomography (CT) was used as guidance in 73 (38 children and 35 adults) patients and magnetic resonance imaging (MRI) in 9 (3 children and 6 adults). The biopsy was performed in a procedure room under local anesthesia in most adults, while children required sedation. Glioblastoma comprised 29.3% of all pathologies in children, compared with only 4.9% of the pathologies in adult population (P = 0.007). Tuberculosis was the next major diagnosis (9.8%). In 12 patients, initial biopsy was inconclusive. Following a repeat biopsy in 5 of these patients, a diagnosis was possible for 75/82 (91.5%) patients by STB. The location of the target, the choice of entry, the radiological characteristic of the lesion, enhancement pattern, and age group did not significantly correlate with the occurrence of inconclusive biopsy. Permanent complications occurred in two patients (2.4%). There was no mortality in this series.

CONCLUSION

Stereotactic biopsy has an important role in brainstem lesions, more significantly in adults, due to wider pathological spectrum. It can be performed safely under local anesthesia through a twist drill craniostomy in most of the adults.

Implications of MGMT methylation status in pituitary adenoma

BACKGROUND

Very little literature exists on frequency of MGMT methylation status in pituitary adenoma. We assessed the frequency of MGMT methylation and protein expression in pituitary adenoma and correlated with patients' age group and prognosis.

METHODS

Tumor tissues from 30 patients with pituitary adenoma were evaluated for MGMT promoter methylation status by methylation specific PCR method. All tumors were also immunostained with MIB-1, anti-p53 and anti-MGMT antibodies.

RESULTS

MGMT methylation status was noted in 40% of cases (7/20 non-functioning adenomas and 5/10 functioning adenomas). MGMT protein expression on IHC was noted in 72.2% of unmethylated tumors, while only 41.6% of methylated tumors demonstrated protein expression. The mean labeling index of MGMT protein was higher in unmethylated tumors as compared to the methylated group, though the difference was not statistically significant (18.6% vs 8.8%; p=0.131). Tumor regrowth occurred in four unmethylated tumors as compared to none in methylated group. Even though there was no correlation between patient age and MGMT methylation status (p=0.823), we noted that the frequency of methylation in middle age patients (between 30 and 59 yrs) was 64.7%, which was higher compared to other age groups.

CONCLUSION

This is the first study from India showing MGMT promoter methylation status with protein expression in pituitary adenoma. We noted that tumor regrowth was higher in unmethylated tumors.

Rosette-forming glioneuronal tumor -- evidence of stem cell origin with biphenotypic differentiation

Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a new addition to the WHO classification of central nervous system tumors. To date, 72 cases have been described in literature. In the present study, we report the clinical and imaging features, with detailed histopathological and immunohistochemical profile, of eight cases. Confocal microscopic evidence of stem cell origin with biphenotypic, glial and neurocytic differentiation is presented with a comprehensive review of literature.

Expression pattern and prognostic significance of IGFBP isoforms in anaplastic astrocytoma

The role of insulin-like growth factors and their regulatory proteins (IGFBP isoforms) in gliomas, particularly glioblastoma, has been a subject of active research in recent years. There is paucity of literature on their expression and impact on clinical outcome in anaplastic astrocytomas. To evaluate the expression patterns of IGFBP isoforms in anaplastic astrocytoma and correlate with clinical outcome, a retrospective study of 53 adult patients operated for supratentorial lobar anaplastic astrocytoma was performed. The protein expression of IGFBP isoforms (IGFBP-2, -3, -5 and -7), was studied by immunohistochemistry on all samples. The patients were followed up and outcome was documented. The median age at presentation in the present study was 35 years. The pattern of staining was intra cytoplasmic, homogenous and diffuse for IGFBP-2, -3 and -5 and granular for IGFBP-7. IGFBP-2 expression was significantly low in anaplastic astrocytoma as compared to other isoforms (P < 0.001). IGFBP-3 expression was higher than the other isoforms. However, its' expression correlated with favorable overall survival and demonstrated a trend towards significance on univariate analysis. The present study is the first of its kind to describe comprehensively the pattern of expression of IGFBP isoforms (IGFBP-2, -3, -5 and -7) in anaplastic astrocytomas. IGFBP-2 and IGFBP-3 expression patterns and correlation to prognosis were distinct in anaplastic astrocytoma patients, contradictory to what has been reported in glioblastoma, thus giving further evidence that anaplastic astrocytomas are molecularly distinct from glioblastoma.

Age-dependent prognostic effects of EGFR/p53 alterations in glioblastoma: study on a prospective cohort of 140 uniformly treated adult patients

AIMS

To assess the prognostic influence of EGFR amplification/overexpression, p53 immunoreactivity and their age-dependent prognostic effects in a large prospective cohort of uniformly treated adult patients with newly diagnosed glioblastoma.

METHODS

Tumours from a uniformly treated prospective cohort of adult patients with newly diagnosed glioblastoma (n=140) were examined for EGFR amplification by fluorescence in situ hybridisation and EGFR/p53 expression by immunohistochemistry. Statistical methods were employed to assess the degree of association between EGFR amplification/overexpression and p53 immunopositivity. Survival analyses were performed by employing Cox proportional hazard models to assess the independent prognostic value of EGFR/p53 alterations and test the propensity for risk with age by assessing their interaction with patient age.

RESULTS

A strong positive correlation between EGFR amplification and EGFR overexpression (rho=0.5157; p<0.0001; CI 0.3783 to 0.6309) and a negative association of EGFR amplification (rho=-0.3417; p<0.0001; CI -0.4842 to -0.1816) and EGFR overexpression (rho=-0.3095; p<0.001; CI -0.4561 to -0.1465) with p53 immunopositivity was observed. Only patient age (HR: 1.029; p=0.004; CI 1.009 to 1.049) was associated with shorter survival by univariate Cox regression analysis. Multivariable Cox proportional hazards models revealed a statistically significant interaction between EGFR overexpression and age to be associated with shorter survival (HR: 1.001; p<0.0001; CI 1.000 to 1.002), thus predicting a higher hazard with increasing age. No age interaction of EGFR amplification status (HR: 1.001; p=0.642; CI 0.995 to 1.008) and p53 immunopositivity (HR: 1.000; p=0.841; CI 0.999 to 1.001) was noted in this cohort.

CONCLUSIONS

The prognostic value of EGFR overexpression is age-dependent, and there is a propensity for a higher hazard with increasing patient age. Identifying such groups of patients with more aggressive disease becomes mandatory, since they would benefit from intense therapeutic protocols targeting EGFR.

Clinical and immunohistochemical prognostic factors in adult glioblastoma patients

OBJECTIVE

Glioblastomas are the commonest and the most malignant of all adult brain tumors, characterized by genetic instability, intratumoral histopathological variability, and unpredictable clinical behavior. The utility of tumor markers that reflect their underlying biology is becoming increasingly important with respect to patient prognostication and their potential role as molecular targets of therapy is being recognized. In this study, we aimed to identify the clinical factors and some immunohistochemical markers that could have an effect on patient survival in supratentorial glioblastomas.

MATERIALS AND METHODS

We evaluated 54 cases of adult supratentorial glioblastomas operated over a span of 1 year, with respect to clinical features such as age, Karnofsky performance score (KPS), extent of resection, adjuvant therapy, and immunohistochemical expression of p53, EGFR (Epidermal Growth Factor Receptor) and PTEN (Phosphatase and Tensin homolog).

RESULTS

Radiotherapy and KPS at presentation were significant predictors of outcome in both univariate and multivariate analyses. Among immunohistochemical variables; loss of PTEN expression in association with over-expression of EGFR showed a trend towards poorer survival, in univariate analysis. Over-expression of EGFR and/or p53 emerged as significant predictors of poor outcome on multivariate analysis, despite failing to prognosticate on univariate analysis.

CONCLUSIONS

Our study shows that EGFR and p53 overexpression along with loss of PTEN expression are important adjuncts to clinical variables in prognosticating glioblastoma patients.

Haemangioma calcificans

Haemangioma calcificans is a relatively rare intracranial tumour, which is characterized by the presence of a calcified nodule in or near the brain. The patient is most often an adult of either sex, who develops seizures. The lesion can be large enough to produce raised intracranial pressure. The location of tumour is subcortical and often in the temporal lobe. It is usually solitary and benign in nature. Microscopically, there are thin-walled blood vessels separated by dense fibrous bands containing deposits of haemosiderin and calcium. On electron microscopy, tubular structures limited by a wall of electrodense material and irregular calcium deposits within them are prominent features. Four cases of haemangioma calcificans are described here with review of literature.

Cestode parasitic infestation: intracranial and spinal hydatid disease--a clinicopathological study of 29 cases from South India

In developing countries hydatidosis is both a medical and economic problem related to environmental hygiene and healthy veterinary practice. This cestode parasitic infestation, uncommonly involving the nervous system, presents with varied clinical manifestation, at times causing diagnostic dilemmas. Multiple intracranial and spinal hydatidosis is rare. A series of 29 histologically confirmed cases of hydatidosis of neuraxis (21 intracranial and 8 spinal) from South India are presented. Among the 21 cases of intracranial hydatidosis, 12 cases were in pediatric age, while only 1 spinal lesion was noted in a 5-year-old child. The clinical presentation of intracranial lesions was predominantly that of raised intracranial pressure and visual symptoms, while spinal hydatidosis manifested with severe back pain, weakness and sphincter disturbances. The cranial cysts were usually single and uniloculated (12 cases), multiple in 7 and single but multiloculated in 2. In spinal hydatidosis, the cysts are usually multiple and extradural, rare ones being intramedullary and intradural. Based on clinical features and imaging, the differential diagnosis for intracranial lesions were cystic tumors and arachnoid cyst while metastasis and tuberculosis were considered in cases of spinal hydatidosis because of vertebral bony involvement. The majority of the cysts could be surgically resected totally and some were aspirated under control suction and resected. None of the cases had anaphylactic reaction, with no significant post-operative morbidity and no mortality. One intracranial and 2 spinal lesions caused by fertile cysts recurred to undergo repeated surgery.

Cerebral zygomycosis

Fifty-six patients with cerebral zygomycosis (mucormycosis) were seen during the period 1971-2001 in two tertiary care hospitals located in south India with tropical climate and catering to neurological diseases. Forty-four patients had rhinocerebral and twelve patients had isolated central nervous system (CNS) zygomycosis. Of these, ten were culture proven (Rhizopus oryzae in eight and Mucor in two); 30 were diagnosed as probable and 16 were diagnosed possible; mixed infections were seen in three patients. Diabetes mellitus was the predisposing condition in a majority (31/44) of patients with the rhinocerebral form of zygomycosis. The tissue obtained at biopsy/autopsy in either form showed necrotic/infarcted tissue with neutrophilic infiltration with broad non-septate hyphae showing irregular branching. The outcome was poor despite surgical excision and antifungal therapy. The high concentration of spores in a mouldy environment, the bird population and improper disposal of hospital waste may facilitate healthy hosts presenting with primary CNS disease.

Expression of p53, EGFR, pRb and bcl-2 proteins in pediatric glioblastoma multiforme: a study of 54 patients

Pediatric glioblastoma multiforme (GBM) tumors, which have been established as 'de novo' neoplasms, are known to differ from their adult counterparts in terms of biology, genetics and ultimately survival of patients. In order to evaluate the utility of markers of tumor biology for refining prognostic assessment, we retrospectively analyzed 54 pediatric GBMs (age range 9 months to 15 years) occurring at different anatomical sites in the brain, operated at our institute between 1995 and 2001. The expression of p53, epidermal growth factor receptor (EGFR), bcl-2 and retinoblastoma proteins (pRb) was analyzed by immunohistochemistry and the results were compared with the clinical profile, MIB-1 labeling index (LI) and patient survival. p53 immunoreactivity was noted in 53.7% of cases, predominantly in thalamic (75%) and cerebral lobar (62.2%), followed by brainstem tumors (30%). It was absent in cerebellar tumors. p53-positive tumors had a higher MIB-1 LI, compared to p53-negative tumors (p=0.003). EGFR and bcl-2 overexpression was observed in 25.9% and 33.3% of cases, respectively, and loss of pRb expression was evident in only 7.4% of cases, indicating that loss of this gene function is not significantly involved in pediatric GBMs. p53 and bcl-2 expression were maximally noted in patients with poorer outcome. Our results indicate that p53 expression status is noted in a significant number of pediatric supratentorial neoplasms. p53 with bcl-2 overexpression is more often associated with ominous prognosis. Further molecular characterization would provide newer insights into the biology of these neoplasms and form a basis for future therapeutic decision making.

Intramedullary glioependymal cyst and tethered cord in an infant

INTRODUCTION

Intramedullary glioependymal cysts are rare congenital lesions of the spinal cord. Their association with another congenital lesion, i.e., tethered cord, is rarer still.

RESULTS AND DISCUSSION

We present a case of intramedullary glioependymal cyst with a filar lipoma in an infant. The clinical features, terminology and pathogenesis are discussed. Many varieties of spinal cysts have been described. It is now believed that simple ciliated or goblet-containing intracranial and intraspinal cysts are endodermal rather than glioependymal in origin. The diagnostic criteria, too, have been defined. Although many of these lesions are developmental in origin their association with other congenital anomalies is rare.

Medulloblastoma with extensive nodularity: a variant occurring in the very young-clinicopathological and immunohistochemical study of four cases

CASE REPORT

Four cases of medulloblastoma with extensive nodularity (MBEN) are described. The patients were 3 years of age or younger at diagnosis. Cranial CT scan disclosed multiple coalescing nodules with peculiar 'grape-like' architecture in three patients. A near total excision of the tumour was performed in all four patients. The patients are currently receiving radiation and chemotherapy. Histologically, the tumours were characterized by extreme nodularity with intranodular uniformity and low proliferative index. The internodular zones were extremely cellular, composed of undifferentiated, mitotically active cells. Bcl-2 protein expression was observed in the cellular zones but was distinctly absent within nodules.

DISCUSSION

MBEN represents a variant that occurs in very young children but has a good prognosis. The favourable outcome is probably related to its spontaneous neurocytic differentiation. The pattern of Bcl-2 immunoreactivity in MBENs indicates that this protein could be a key player in the regulation of neuronal differentiation in medulloblastomas.

Holoprosencephaly with cyclopia--report of a pathological study

A rare case of a lobar holoprosencephaly with cyclopia, associated with non-nervous system anomalies is being reported.

Tuberculous osteitis of clivus

Tuberculous osteitis of clivus is rare. Its diagnosis is difficult because of the rarity of the site and the non-specific nature of the disease. Management consists of confirmation of diagnosis by biopsy and chemotherapy with anti-tubercular drugs. Meningitis may complicate the clinical course, increase morbidity and mortality.

Unusual case of multiple cellular and malignant schwannomas of the cranial and spinal nerves

Schwannomas from cranial nerves and spinal roots are most often benign, malignant schwannomas being uncommon in this location. This report describes a unique case of multiple cellular and malignant schwannomas of the cranial and spinal nerves in a patient with features of neurofibromatosis 2. The tumors were arising from left optic, bilateral oculomotor, trochlear, abducent and vestibular nerves, the left facial and the spinal lumbar nerve roots. The tumor arising from the right trochlear nerve was seen excavating into the hippocampus and the left vestibular nerve into the medulla. In addition, the patient had nodular schwannomas adherent to the inferior surface of the optic chiasm and the cerebellum away from the cranial nerves. Hyperplastic schwannosis was noted in perivascular spaces of thalamus, cerebellum and hippocampus on both sides away from the main lesions. The immunohistochemical and ultrastructural profiles of the tumors suggest that neurofibromas and schwannomas are probably not distinct tumors but lie within a spectrum that differs histologically depending on the predominant cell type.

Glioneuronal migration and development disorders: histological and immunohistochemical study with a comment on evolution

Glioneuronal migration disorders of the brain evolve primarily due to aberration in neuronal migration, maturation and programming in the development of various topographic zones in the brain, following pathological alterations in glial and neuronal interactions. These are broadly referred as cortical dysplastic conditions. While these dysplastic conditions involving cerebral cortex present as drug resistant seizure disorder, those involving cerebellum present as mass lesions or slowly progressing vertigo. We report 17 cases, representing the histological spectrum of dysplastic, glioneuronal migration disorders which include, hemimegalencephaly (1), tuberous sclerosis (4), Sturge Weber Syndrome with focal dysplasia (1), Dysembryoplastic neuroepithelial tumor (7) and Lhermitte Ductos disease of cerebellum (2). The dysplastic neurons in varied stages of maturation showed neuronal cytoskeletal pathology similar to that in neuro degenerative diseases, especially when associated with cytomegaly. Similarly, cells exhibiting dual expression of glial and neuronal markers were noted in the cerebral dysplastic lesions. The dysplastic glial elements probably form the subependymal giant cell astrocytomas. Dysplastic neuronal elements form the nidus for DNT. When localized, surgical resection ameliorate the symptoms in many of these condition. Study of these conditions provide better insight into glioneuronal interaction and maturation of the brain.

Brain biopsy in Creutzfeldt-Jakob disease: evolution of pathological changes by prion protein immunohistochemistry

The formation of protease-resistant prion protein (PrPsc) is considered to be an early event in the pathogenesis of Creutzfeldt-Jakob disease (CJD) and hence its demonstration in brain biopsies by immunohistochemistry is considered diagnostic. We analysed eight brain biopsies from the frontal cortex collected from different parts of India from cases diagnosed as CJD on clinical and pathological grounds for the expression of prion protein (PrP). The duration of illness in these cases varied from 2 months to 1 year. Immunohistochemistry was carried out on paraffin sections using two different clones (KG9 and 3F4) of monoclonal antibodies to PrP. Although all eight cases showed classical features of spongiform encephalopathy of varying severity, only five of the eight cases revealed PrP(sc) in the brain tissue. The immunolabelling was focal and all areas with spongiform change were not labelled. A temporal evolution in the staining pattern was evident - particulate diffuse labelling (synaptic type) in early stages (2 months), perivacuolar deposits in intermediate stages (5-6 months), and dense plaques in late stages (12 months).

Intracranial haemorrhage resulting from unsuspected choriocarcinoma metastasis

A retrospective analysis of clinicopathological data of 10 patients with clinically unsuspected cerebral metastatic choriocarcinoma was carried out. All patients were young adult females. History of preceding pregnancy/abortion was forthcoming in 5 cases but none had a prior history of abnormal gestation. Features of raised intracranial tension followed by hemiparesis were the commonest presenting symptoms. A clinicoradiologic diagnosis of intracerebral haemorrhagic mass, either primary or secondary to tumour bleed, cortico-venous thrombosis or arteriovenous malformation, was entertained in 8 out of 10 cases. In other two cases, ring enhancing lesions prompted the diagnosis of granulomatous masses. Eight patients were operated upon, of whom two died after short hospital stay, and were autopsied. All had haemorrhagic masses noted at surgery/autopsy. Accurate diagnosis of metastatic choriocarcinoma was established only by histologic examination of these haemorrhages. This report emphasizes the importance of considering metastatic choriocarcinoma as an important differential diagnosis of haemorrhagic intracerebral lesions in women of child bearing age group. Measurement of serum/CSF level of HCG in suspected cases helps to implement early therapy. The diagnostic value of histopathologic examination of surgically resected blood clots in determining aetiology of intracerebral haemorrhagic masses is highlighted.

Hypothalamic tumour with haemorrhage

Haemorrhage in low-grade glioma is rare. A 4-year-old boy presented with sudden loss of consciousness. CT scan of his head revealed anterior third ventricular tumour with bleeding, intraventricular haemorrhage and hydrocephalus. The boy expired within 26 h of the onset of his illness, and an autopsy revealed a haemorrhagic juvenile pilocytic astrocytoma arising from the lateral hypothalamus with intraventricular haemorrhage. Intracranial tumour as the cause of sudden death and tumour with bleeding are discussed.

Vasculitic neuropathy in HIV infection: a clinicopathological study

Vasculitis causing peripheral neuropathy may be the first sign of HIV infection. We report four such cases in whom the onset of peripheral neuropathy led to the detection of HIV infection. Two patients presented with features of mononeuritis multiplex, while the other two had a lumbosacral polyradiculopathy. A prior history of blood transfusion was forthcoming in one of the patients. Sural nerve biopsies in all the four cases and the muscle biopsy in two, histologically showed evidence of vasculitis. Immunohistochemically, the viral antigen was not demonstrable in any of the biopsies, but on electron microscope, virus-like particles were identifiable in the Schwann cell cytoplasm and the perivascular macrophages in one case. To the best of our knowledge, this is the only report that has documented the virus in the Schwann cells as well as the perivascular macrophages lending credence to the fact that these viruses are neurotropic as well as lymphotropic. Immunoglobulin deposits were not demonstrable in any of the cases, suggesting that direct viral invasion may have a role in the pathogenesis of peripheral nerve vasculitis.

Aneurysmal bone cyst of the temporal bone

Aneurysmal bone cysts are uncommon lesions of the bone, which are benign and non-neoplastic in nature. They are commonly seen in the long bones. Their occurrence in the calvarium is rare. We report the occurrence of an aneurysmal bone cyst in the temporal bone of a young boy, which eroded the posterior part of the orbit to cause proptosis.

Giant orbital and intracranial xanthogranuloma--a short report

Xanthogranuloma are known to arise in the paranasal sinus or orbit. They may also arise primarily in the brain. Those arising from the sinuses or orbit might involve the intracranial cavity to some extent. But an extensive involvement of the cranial compartment is very rare. This report describes one such case.

Stroke in a young man with fibromuscular dysplasia of the cranial vessels with anticardiolipin antibodies: a case report

A case of fibromuscular dysplasia (FMD), presenting with a non-hemorrhagic infarct is reported. Positivity of anticardiolipin antibodies suggested an immune response. A 40-year-old man presented with sudden onset of stroke, preceded by similar ischemic attacks. Computed tomography (CT) of the brain showed a recent non-hemorrhagic infarct in the left middle cerebral artery (MCA) territory and an old right MCA territory infarct. Serum was positive for anticardiolipin antibodies. These above findings were confirmed at autopsy. A portion of the internal carotid artery and the middle cerebral arteries on both sides revealed features of FMD, with thrombosis. This case suggests an immune mechanism for FMD, hitherto unobserved in the cerebral circulation.

Cryptococcosis in the immunocompromised host with special reference to AIDS

Cryptococcosis is increasing because of an ever rising population of immunocompromised individuals especially those with acquired immune deficiency syndrome (AIDS). Cryptococcal infection of the central nervous system (CNS) were diagnosed in 149 cases over a period of 19.5 years (January 1978-June 1998). Culture was positive in all cases except three who were already on antifungal therapy. India ink mounts of cerebrospinal fluid (CSF) revealed encapsulated cryptococci in 134, and cryptococcal antigen was detected in 111 of 114 patients tested. A comparison of laboratory and certain clinical parameters in patients with and without associated HIV infection showed that a poor CSF cell response and culture of cryptococci from extra-neural sites was more often associated with HIV infection and was statistically significant. Further, presence of concomitant infection especially tuberculosis, and mortality were higher in the HIV positive group.

Infantile neuroaxonal dystrophy and giant axonal neuropathy--overlap diseases of neuronal cytoskeletal elements in childhood?

Giant axonal neuropathy (GAN) and infantile neuroaxonal dystrophy (INAD) are two progressive neurodegenerative disorders of childhood that have considerable clinical as well as histological overlap but are believed to be ultrastructurally distinct. The clinicopathological and ultrastructural features of three cases of INAD, two of whom are siblings and one case of GAN are described. The sural nerve biopsies in all four cases were essentially similar on light microscopy revealing giant axons. On electron microscopy, the findings in the case of GAN were typical with dense accumulation of neurofilaments within the giant axons. In the three cases of INAD, too, in addition to accumulation of mitochondria and organelles with vesiculotubular profiles, a similar increase in neurofilaments was evident. We, therefore, believe that these two disorders may represent a spectrum in evolution of intermediate filament pathology with various organelles participating in the temporal evolution of the disease process.

Giant intramedullary teratoma in an infant

Teratomas are uncommon tumors of the nervous system, the commonest site being the pineal region. Spinal teratomas are very rare apart from the sacrococcygeal variety. The authors report the occurrence of an intramedullary teratoma in an infant. The clinical features, imaging studies and the pathology are discussed. In addition the literature is also reviewed.

Primary angiitis of CNS : neuropathological study of three autopsied cases with brief review of literature

Primary angiitis of CNS(PACNS) or granulomatous angiitis of CNS is a rare inflammatory disease of small blood vessels mostly confined to the CNS. The clinical and pathological features of 3 autopsied cases are described. Clinically all the three PACNS patients were young males, age ranging from 19 to 31 years. All presented with varied neurological manifestations. There was no evidence of systemic disease in any of the cases. The ESR was normal and CSF analysis showed chronic meningitic pattern. The cerebral angiogram in one case was normal and the CT scan done in another case showed multiple intracerebral haematoma due to vasculitis. Brain biopsy was not done. Diagnosis was made at post-mortem examination. Histology showed characteristic but variable degree of granulomatous and non-granulomatous angiitis of small vessels. Venulitis with parenchymal haemorrhages was the predominant feature and in one case phlebitis with thrombosis was noted. Since the disease responds to steroids and immunosuppressive therapy, establishing antemortem diagnosis is important. In view of the association of angiitis of CNS with bacteria and viral infections, their role in the evolution of the disease needs to be investigated.

Medulloepithelioma of the optic nerve with intradural extension--report of two cases and a review of the literature

Medulloepithelioma is an uncommon tumour. Among the various sites of origin the optic nerve is rare. We report here two cases of medulloepithelioma of the optic nerve that had extended intradurally into the cranial cavity. A review of the published cases is also given.

Pathology of Madras type of motor neuron disease (MMND)--a histological and immunohistochemical study

A neuropathological report of Madras type of motor neuron disease (MMND) is presented and the differences from other forms of MND are discussed. An 18-year-old girl presented with nerve deafness and slowly progressive bulbo-spinal muscular atrophy, characteristic of MMND. Post-mortem examination of the spinal cord showed a severe loss of anterior horn cells, prominent dilatation of vessels, diffuse, but sparse sprinkling of microglial cells and lymphocytes, and demyelination and sclerosis of the ventrolateral columns. Neuronal depletion and marked gliosis was noted in the cochlear nucleus on both sides, while other bulbar motor nuclei were also involved. The cochlear nerve showed demyelination and axonal loss. Trigeminal and vestibular ganglia revealed features of ganglionitis. The possibility of an inflammatory aetiology for MMND needs to be considered.

Centronuclear myopathy--morphological relation to developing human skeletal muscle: a clinicopathological evaluation

Centronuclear myopathy (CNM), an uncommon condition, is one of the congenital myopathies. It is believed to arise as a result of maturational arrest, with persistence of myotubes postnatally. However, denervation being the basic disease process and its possible influence on central nervous system causing defect in nuclear migration has also been postulated. Keeping in view these existing controversies, we have studied 17 cases of CNM (neonatal - 1, childhood - 13, adulthood - 3) during the last twelve and a half years. Diagnosis was based on histological and enzyme histochemical findings of muscle biopsy along with clinical data. Ultrastructural characterstics of muscle have been studied in 10 cases. The affected muscle fibres showed a central nucleus (40-99%) with perinuclear halo. Type I fibre predominance with hypoplasia was consistently seen. Fibre type disproportion was noticed in 7 cases. The neonatal form revealed dense oxidative enzyme reaction product in the centre. The morphological features of CNM were compared with foetal skeletal muscles obtained at gestational ages ranging from 9 weeks - 36 weeks (n = 18). In the severe neonatal form th myofibres resembled the foetal myotubes. In the less severe childhood and adult form of CNM, aberrant organization of cytoskeletal network might have played a pathogenetic role in causing the disease.

Expression of p67 (Munc-18) in adult human brain and neuroectodermal tumors of human central nervous system

p67 (Munc-18), is a neuron-specific protein of 67 kDa, known for its ability to bind with syntaxin and also to copurify with neuronal cdc2-like kinase. Earlier, in situ hybridization and immunocytochemical analysis of rat trigeminal ganglion and hippocampal cells demonstrated the specific localization of p67 in nerve cells and its rich distribution in axons. In the present study, we have looked for p67 expression in normal human brain and various neuroectodermal tumors. Immunohistochemical and Western immunoblot analysis of normal human brain tissue using antibodies against the N- and C-termini of p67 demonstrated the specific localization of this protein in postmitotic neurons but not in glia. Among neuroectodermal tumors, expression of p67 was observed in 100% of the tumors of neuronal origin studied, especially in the mature neuronal cell population of these tumors. Western immunoblot analysis of non-neuronal neuroectodermal tumors failed to reveal the expression of this protein in majority of cases. However, in gliomas and meningiomas, mild cytoplasmic immunohistochemical staining of neoplastic cells was noted in 64.7% and 25% of cases, respectively. Observed mild immunohistochemical staining of these tumors could be due to immunoreactivity to low molecular weight degraded products of p67, as seen on Western blot. The findings suggest that p67, by virtue of its ability to be expressed in postmitotic neurons of adult human brain and in tumors of neuronal origin, may serve as a molecular tool to understand the growth and differentiation of the nervous system in general.

Inclusion body myositis (IBM)

Clinical, histological, immunohistochemical and ultrastructural features of 5 cases of inclusion body myositis -4 sporadic (s-IBM) and one hereditary (h-IBM) form are described. These patients (3 men, 2 women) had chronic progressive weakness of varying severity in all 4 extremities with sparing of cranial muscles. Elevation of CPK was noted in 2 patients. Electromyography revealed features of myopathy in 4 and additional neurogenic changes in 2 subjects. Clinical diagnosis was often other than inclusion body myositis. Presence of characteristic eosinophilic inclusions within the vacuoles established the diagnosis. The inclusions were congophilic and showed positivity to ubiquitin, beta-amyloid and SMI-31 in the sporadic cases while congophila was absent in the hereditary form. Immunostaining to hyperphosphorylated-tau was negative in both s-IBM and h-IBM. Membraneous whorls were observed at ultrastructural level. None of the patients improved with steroids and trial with other immunosuppressants was unsuccessful.

Profile of neurologic disorders associated with HIV/AIDS from Bangalore, south India (1989-96)

One hundred patients (95 males, 5 females, mean age at presentation 31.6 +/- 9.4 yr) with various neurological disorders associated with HIV infection during 1989-1996 were evaluated at NIMHANS, Bangalore. Eighty patients belonged to group I associated with opportunistic neuroinfections and 20 to group II--non infectious neurological disorders. Cryptococcal meningitis either alone (n = 31) or associated with tuberculous meningitis (n = 6) was the most common (46.3%) followed by neurotuberculosis either alone (n = 24) or with cerebral toxoplasmosis (n = 4) accounting for 35 per cent. Other opportunistic neuroinfections included cerebral toxoplasmosis, herpes zoster, fulminant pyogenic meningitis and neurosyphilis. Clinical characteristics, diagnostic clues, their laboratory and radiological profiles and problems encountered in diagnosis and management of these opportunistic infections are highlighted. In group II (19 males and one female; mean age of 32.6 +/- 9.4 yr), two patients had cortical dementia, three acute brain stem involvement, two epilepsy and one had features suggestive of progressive multifocal leukoencephalopathy. Two patients of group I during follow up developed cortical dementia. Six had peripheral nervous system involvement similar to Guillain-Barre syndrome. Sixty six patients (63 of group I and 3 of group II) progressed to AIDS, 33 patients from group I and one patient from group II succumbed to the disease. With the rapid increase in the incidence of HIV/AIDS and an increase in the neurological manifestations of HIV/AIDS it is important to recognise the magnitude of the problem for health planning in India.

Intraventricular tuberculous abscess: a case report

Ventricles can be involved in different ways in neurotuberculosis, however, the occurrence of intraventricular abscess has been rarely reported. We report a young woman who had intraventricular tubercular abscess. Cranial computed tomographic scan showed hypodense ring enhancing lesion in the right lateral ventricle with unilateral hydrocephalus. She underwent parasagittal craniotomy with total excision of the lesion. The pus obtained from the lesion was teeming with acid fast bacilli.

Pseudo-aneurysm of the carotid bifurcation secondary to radiation

Pseudoaneurysms of the extracranial carotid vessels have a varied etiopathogenesis. Cases have been attributed to spontaneous rupture, following tonsillectomy or peritonsillar abscesses, trauma, postanastamotic and, rarely, postirradiation, and ECMO. The authors present a case of a pseudoaneurysm involving the carotid artery bifurcation following radiation therapy. A saphenous vein graft was used to establish continuity between the common and the internal carotid arteries. A vascular shunt was used to maintain cerebral perfusion during surgery. This case highlights the technical difficulties encountered in correcting this condition. This case exemplifies the technical difficulties that are encountered in a complicated case such as this. Numerous previous operations and radiotherapy compounded the hazards of the surgical procedure. Although technically challenging, every attempt must be made to resect pseudoaneurysms caused by radiation induced vascular damage.