Neuromuscular pathology

In this chapter, we discuss the indications for muscle, nerve, and skin biopsies, the techniques and normal processing of biopsy specimens, normal histological appearance, and the commonest histopathological abnormalities of different myopathies and neuropathies.

Corticotroph hyperplasia and Cushing disease: diagnostic features and surgical management

OBJECTIVE

This study was done to compare corticotroph hyperplasia and histopathologically proven adenomas in patients with Cushing disease by analyzing diagnostic features, surgical management, and clinical outcomes.

METHODS

Patients with suspected pituitary Cushing disease were included in a retrospective cohort study and were excluded if results of pathological analysis of the surgical specimen were nondiagnostic or normal. Cases were reviewed by two experienced neuropathologists. Total lesion removal was used as a dichotomized surgical variable; it was defined as an extracapsular resection (including a rim of normal gland) in patients with an adenoma, and for hyperplasia patients it was defined as removal of the presumed lesion plus a rim of surrounding normal gland. Bivariate and multivariate analyses were performed. Recurrence-free survival was compared between the two groups.

RESULTS

The final cohort consisted of 63 patients (15 with hyperplasia and 48 with adenoma). Normal pituitary acinar architecture was highly variable. Corticotroph hyperplasia was diagnosed based on the presence of expanded acini showing retained reticulin architecture and predominant staining for adrenocorticotropic hormone. Crooke's hyaline change was seen in 46.7% of specimens, and its frequency was equal in nonlesional tissue of both groups. The two groups differed only by MRI findings (equivocal/diffuse lesion in 46% of hyperplasia and 17% of adenoma; p = 0.03). Diagnostic uncertainty in the hyperplasia group resulted in additional confirmatory testing by 24-hour urinary free cortisol. Total lesion removal was infrequent in patients with hyperplasia compared to those with adenoma (33% vs 65%; p = 0.03). Initial biochemical remission was similar (67% in hyperplasia and 85% in adenoma; p = 0.11). There was no difference in hypothalamic-pituitary-adrenal axis recovery or disease recurrence. The median follow-up was 1.9 years (IQR 0.7-7.6 years) for the hyperplasia group and 1.2 years (IQR 0.4-2.4 years) for the adenoma group. Lack of a discrete lesion and diagnostic uncertainty were the only significant predictors of hyperplasia (sensitivity 53.3%, specificity 97.7%, positive predictive value 88.9%, negative predictive value 85.7%). An adjusted Cox proportional hazards model showed similar recurrence-free survival in the two groups.

CONCLUSIONS

This study suggests an association between biochemically proven Cushing disease and histopathologically proven corticotroph hyperplasia. Imaging and operative findings can be ambiguous, and, compared to typical adenomas with a pseudocapsule, the surgical approach is more nuanced. Nevertheless, if treated appropriately, biochemical outcomes may be similar.

Surgical resection of granular cell tumor of the sellar region: three indications

PURPOSE

This case series evaluates the surgical management of granular cell tumor (GCT) of the sellar region. This rare entity presents a unique diagnostic and surgical challenge.

METHODS

Institutional neuropathology databases at Brigham and Women's Hospital and Massachusetts General Hospital were searched for cases with a tissue diagnosis of GCT, and with a location in the sellar region. Patient, treatment, tumor, and follow-up data were extracted.

RESULTS

Three patients had a diagnosis of GCT of the sellar region occurring over an 18-year period. All three patients were followed postoperatively at our multidisciplinary pituitary center (median follow-up = 30 months; range 12-30 months). Hormonal disturbances, an incidental lesion requiring diagnosis, and neurological symptoms were indications for surgery in these patients. Two patients underwent a craniotomy and one underwent endoscopic transsphenoidal surgery. All three patients were free of tumor recurrence at last follow-up. In one case tested, positive thyroid transcription factor-1 (TTF-1) immunohistochemistry was observed.

CONCLUSION

GCT is generally a benign tumor of the sellar region. Surgical resection is the standard treatment, more recently with transsphenoidal surgery when indicated. Surgical resection results in optimal outcome for patients.

Fatal Powassan Encephalitis (Deer Tick Virus, Lineage II) in a Patient With Fever and Orchitis Receiving Rituximab

Importance

Powassan virus is a rare but increasingly recognized cause of severe neurological disease.

Objective

To highlight the diagnostic challenges and neuropathological findings in a fatal case of Powassan encephalitis caused by deer tick virus (lineage II) in a patient with follicular lymphoma receiving rituximab, with nonspecific anti-GAD65 antibodies, who was initially seen with fever and orchiepididymitis.

Design, Setting, and Participants

Comparison of clinical, radiological, histological, and laboratory findings, including immunohistochemistry, real-time polymerase chain reaction, antibody detection, and unbiased sequencing assays, in a single case report (first seen in December 2016) at an academic medical center.

Exposure

Infection with Powassan virus.

Main Outcomes and Measures

Results of individual assays compared retrospectively.

Results

In a 63-year-old man with fatal Powassan encephalitis, serum and cerebrospinal fluid IgM antibodies were not detected via standard methods, likely because of rituximab exposure. Neuropathological findings were extensive, including diffuse leptomeningeal and parenchymal lymphohistiocytic infiltration, microglial proliferation, marked neuronal loss, and white matter microinfarctions most severely involving the cerebellum, thalamus, and basal ganglia. Diagnosis was made after death by 3 independent methods, including demonstration of Powassan virus antigen in brain biopsy and autopsy tissue, detection of viral RNA in serum and cerebrospinal fluid by targeted real-time polymerase chain reaction, and detection of viral RNA in cerebrospinal fluid by unbiased sequencing. Extensive testing for other etiologies yielded negative results, including mumps virus owing to prodromal orchiepididymitis. Low-titer anti-GAD65 antibodies identified in serum, suggestive of limbic encephalitis, were not detected in cerebrospinal fluid.

Conclusions and Relevance

Owing to the rarity of Powassan encephalitis, a high degree of suspicion is required to make the diagnosis, particularly in an immunocompromised patient, in whom antibody-based assays may be falsely negative. Unbiased sequencing assays have the potential to detect uncommon infectious agents and may prove useful in similar scenarios.

Natural history of cranial fibrous dysplasia revealed during long-term follow-up: Case report and literature review

BACKGROUND

Fibrous dysplasia (FD) is a rare developmental disease characterized by the replacement of bone marrow with proliferating fibro-osseous tissue. There exist three forms of FD-monostotic, polyostotic, and that associated with McCune-Albright syndrome. The disease can present in different locations and with a variety of symptoms. One of the more common locations of FD occurrence is the craniofacial region. Treatment of asymptomatic FD often involves conservative management with serial imaging. Medical management with bisphosphonates is an option, though long-term efficacy data are lacking. Surgical resection is usually reserved for very large or symptomatic lesions.

CASE DESCRIPTION

We discuss the most unusual case of a 52-year-old male found to have a left pterional mass while being worked up for sinus headaches. The patient elected to follow this lesion conservatively, and imaging several years later showed obvious growth which accelerated in the last 4 years during an 18-year observational period. He ultimately underwent successful resection of an extradural and intradural FD.

CONCLUSIONS

The significant growth potential of these lesions was revealed in this patient, in whom conservative management had been adopted. Despite optimal surgical resection and outcome in this case, the importance of surveillance imaging and perhaps earlier intervention cannot be underestimated when managing cranial FD.

A Woman in Her 40s With Headache and New-Onset Seizures

A woman in her 40s with a history of plasma cell leukemia presented with 1 month of intermittent headaches followed by a seizure. Results from laboratory studies were notable for a cerebrospinal fluid opening pressure of 28 mm H2O and 8 white blood cells, including 1 atypical plasma cell. Imaging studies revealed confluent bifrontal white matter fluid-attenuated inversion recovery hyperintensities, as well as a contrast-enhancing sellar lesion. The patient underwent a stereotactic biopsy. The differential diagnosis, pathologic findings, and diagnosis are discussed.

Brain and liver pathology, amyloid deposition, and interferon responses among older HIV-positive patients in the late HAART era

Background

HIV+ patients on highly active antiretroviral therapy (HAART) with suppressed viral loads have a low incidence of HIV-associated dementia, but increased prevalence of milder forms of HIV-associated neurocognitive disorders (HAND). These milder forms of HAND are often associated with minimal histological abnormalities, and their pathophysiology is unclear. Comorbidities, altered amyloid metabolism, accelerated brain aging, and activated interferon responses are suspected to play a role in HAND pathogenesis in HAART–treated persons.

Methods

To investigate associations between liver disease, accelerated brain aging, and HAND in HIV+ patients in the late HAART era (2002–2015), we studied liver and brain autopsy tissues from 53 older subjects evaluated at UCLA and BWH using histopathological stains, a sensitive fluorescent amyloid stain (AmyloGlo), and targeted gene expression profiling (NanoString).

Results

The majority of HIV+ subjects (median age 56) were on HAART (89.3%) with last pre-mortem plasma viral load <400 copies/mL (81.5%); 50% had CD4+ counts <200 cells/μL. Compared to HIV- controls (median age 65), HIV+ subjects had more cancer (p = 0.04), illicit drug use (p <0.00001), and HCV co-infection (p = 0.002), less cardiovascular disease (p = 0.03), and similar prevalence of cerebrovascular disease (~40%), hypertension, hyperlipidemia, and diabetes. Deep frontal white matter showed increased gliosis in HIV+ subjects vs. HIV- controls (p = 0.09), but no significant differences in myelin loss, blood vessel thickening, or inflammation. Liver showed more severe fibrosis/cirrhosis (p = 0.02) and less steatosis (p = 0.03) in HIV+ subjects, but no significant differences in inflammation, blood vessel thickness, or pigment deposition. There were no significant associations between liver and brain pathologies. AmyloGlo staining detected large amyloid deposits in only one HIV+ case (age 69 with Alzheimer’s disease pathology) and two HIV- controls (ages 66 and 74). White matter from HIV+ cases vs. HIV- seronegative controls showed a trend (p = 0.06) towards increased interferon response gene expression (ISG15, MX1, IFIT1, IFIT2, and IFITM1).

Conclusions

Gliosis and cerebrovascular disease, but not accelerated amyloid deposition, are common brain pathologies among older HIV+ patients in the late HAART era. Although HIV+ subjects had more cirrhosis, liver pathology was not associated with any consistent pattern of brain pathology. Cerebrovascular disease, interferon responses, and neuroinflammation are likely factors contributing to brain aging and HAND in older HIV+ patients on current HAART regimens.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2246-7) contains supplementary material, which is available to authorized users.

Fatal Eastern Equine Encephalitis in a Patient on Maintenance Rituximab: A Case Report

A 63-year-old woman on rituximab maintenance for follicular lymphoma presented with headaches, vomiting, and fever, and was diagnosed with eastern equine encephalomyelitis by cerebrospinal fluid polymerase chain reaction. Eastern equine encephalomyelitis immunoglobulin (Ig)G/IgM remained negative due to rituximab treatment, and magnetic resonance imaging showed minimal abnormalities, making this a diagnostically challenging case. Despite therapy with intravenous Ig, the patient rapidly declined and died on hospital day 12. Autopsy revealed perivascular and parenchymal chronic inflammation, with an absence of B lymphocytes, and virally infected neurons throughout the central nervous system.

Novel mutation in CNTNAP1 results in congenital hypomyelinating neuropathy

INTRODUCTION

Congenital hypomyelinating neuropathy (CHN) is a rare congenital neuropathy that presents in the neonatal period and has been linked previously to mutations in several genes associated with myelination. A recent study has linked 4 homozygous frameshift mutations in the contactin-associated protein 1 (CNTNAP1) gene with this condition.

METHODS

We report a neonate with CHN who was found to have absent sensory nerve and compound muscle action potentials and hypomyelination on nerve biopsy.

RESULTS

On whole exome sequencing, we identified a novel CNTNAP1 homozygous missense mutation (p.Arg388Pro) in the proband, and both parents were carriers. Molecular modeling suggests that this variant disrupts a β-strand to cause an unstable structure and likely significant changes in protein function.

CONCLUSIONS

This report links a missense CNTNAP1 variant to the disease phenotype previously associated only with frameshift mutations. Muscle Nerve 55: 761-765, 2017.

Functional Gonadotroph Adenomas: Case Series and Report of Literature

BACKGROUND

Functional gonadotroph adenomas (FGAs) are rare tumors of the pituitary gland that secrete biologically active gonadotropins.

OBJECTIVE

To advance clinical understanding of FGAs.

METHODS

We performed a retrospective review of adult patients who underwent resection of a pituitary lesion between August 1997 and October 2014 and remain under care at our center. We identified patients who had pathologic and biochemical confirmation of FGAs, as defined by a lack of serum follicle-stimulating hormone/luteinizing hormone suppression in the setting of elevated gonadal steroids, associated clinical symptoms, or both.

RESULTS

FGAs were documented in 7 patients (5 men, 2 women) over a 17-year period. Clinical findings at presentation included visual field deficits in 5 patients, headache in 3, sexual dysfunction in 3, and ovarian cysts in both women. Each patient underwent lesion resection (6 via the endonasal transsphenoidal approach and 1 via a craniotomy with transsphenoidal reoperation). Analysis of tumor samples revealed immunopositivity for follicle-stimulating hormone/luteinizing hormone in 5 patients and FSH only in 2 patients. Postoperative follow-up (median, 10 months; range, 4-213 months) indicated remission in 6 of 7 patients.

CONCLUSION

An FGA can pose both a diagnostic and a therapeutic challenge. The tumor is often diagnosed as a nonfunctioning macroadenoma after presenting with nonspecific symptoms and is the cause of significant morbidity. An FGA should be considered in the differential diagnosis of patients harboring pituitary adenomas with reproductive dysfunction. Transsphenoidal resection is the initial treatment of choice and can reduce endocrine dysfunction, resolve headaches, improve visual impairment, and provide tissue for detailed analysis.

ABBREVIATIONS

FGA, functional gonadotroph adenomaFSH, follicle-stimulating hormoneLH, luteinizing hormoneTSH, thyroid-stimulating hormone.

Expanding the phenotype associated with the NEFL mutation: neuromuscular disease in a family with overlapping myopathic and neurogenic findings

IMPORTANCE

Newer sequencing technologies in combination with traditional gene mapping techniques, such as linkage analysis, can help identify the genetic basis of disease for patients with rare disorders of uncertain etiology. This approach may expand the phenotypic spectrum of disease associated with those genetic mutations.

OBJECTIVE

To elucidate the molecular cause of a neuromuscular disease among a family in which 4 members, a mother and her 3 sons, were affected.

DESIGN, SETTING, AND PARTICIPANTS

Two of 4 affected members manifested nemaline myopathy, a common subtype of congenital myopathy, while the other 2 had a nonspecific myopathy. Single-nucleotide polymorphism-based linkage analysis was performed on DNA samples from the 4 affected family members, and whole-genome sequencing was performed in the proband. Real-time quantitative reverse transcription-polymerase chain reaction, immunofluorescence, and Western blot analysis were performed on muscle biopsy specimens.

MAIN OUTCOMES AND MEASURES

Whole-genome sequencing and linkage analysis identified a variant in a gene that explains the phenotype.

RESULTS

We identified a novel neurofilament light polypeptide (NEFL) nonsense mutation in all affected members. NEFL mutations have been previously linked to Charcot-Marie-Tooth disease in humans. This led us to reevaluate the diagnosis, and we recognized that several of the findings, especially those related to the muscle biopsy specimens and electromyography, were consistent with a neurogenic disease.

CONCLUSIONS AND RELEVANCE

NEFL mutations are known to cause Charcot-Marie-Tooth disease in humans and motor neuron disease in mice. We report the identification of an NEFL mutation in a family clinically manifesting congenital myopathy. We also describe potential overlap between myopathic and neurogenic findings in this family. These findings expand the phenotypic spectrum of diseases associated with NEFL mutations. This study is an example of the power of genomic approaches to identify potentially pathogenic mutations in unsuspected genes responsible for heterogeneous neuromuscular diseases.

RYR1 mutations as a cause of ophthalmoplegia, facial weakness, and malignant hyperthermia

IMPORTANCE

Total ophthalmoplegia can result from ryanodine receptor 1 (RYR1) mutations without overt associated skeletal myopathy. Patients carrying RYR1 mutations are at high risk of developing malignant hyperthermia. Ophthalmologists should be familiar with these important clinical associations.

OBJECTIVE

To determine the genetic cause of congenital ptosis, ophthalmoplegia, facial paralysis, and mild hypotonia segregating in 2 pedigrees diagnosed with atypical Moebius syndrome or congenital fibrosis of the extraocular muscles.

DESIGN, SETTING, AND PARTICIPANTS

Clinical data including medical and family histories were collected at research laboratories at Boston Children's Hospital and Jules Stein Eye Institute (Engle and Demer labs) for affected and unaffected family members from 2 pedigrees in which patients presented with total ophthalmoplegia, facial weakness, and myopathy.

INTERVENTION

Homozygosity mapping and whole-exome sequencing were conducted to identify causative mutations in affected family members. Histories, physical examinations, and clinical data were reviewed.

MAIN OUTCOME AND MEASURE

Mutations in RYR1.

RESULTS

Missense mutations resulting in 2 homozygous RYR1 amino acid substitutions (E989G and R3772W) and 2 compound heterozygous RYR1 substitutions (H283R and R3772W) were identified in a consanguineous and a nonconsanguineous pedigree, respectively. Orbital magnetic resonance imaging revealed marked hypoplasia of extraocular muscles and intraorbital cranial nerves. Skeletal muscle biopsy specimens revealed nonspecific myopathic changes. Clinically, the patients' ophthalmoplegia and facial weakness were far more significant than their hypotonia and limb weakness and were accompanied by an unrecognized susceptibility to malignant hyperthermia.

CONCLUSIONS AND RELEVANCE

Affected children presenting with severe congenital ophthalmoplegia and facial weakness in the setting of only mild skeletal myopathy harbored recessive mutations in RYR1, encoding the ryanodine receptor 1, and were susceptible to malignant hyperthermia. While ophthalmoplegia occurs rarely in RYR1-related myopathies, these children were atypical because they lacked significant weakness, respiratory insufficiency, or scoliosis. RYR1-associated myopathies should be included in the differential diagnosis of congenital ophthalmoplegia and facial weakness, even without clinical skeletal myopathy. These patients should also be considered susceptible to malignant hyperthermia, a life-threatening anesthetic complication avoidable if anticipated presurgically.

Molecular classification of low-grade diffuse gliomas

The current World Health Organization classification recognizes three histological types of grade II low-grade diffuse glioma (diffuse astrocytoma, oligoastrocytoma, and oligodendroglioma). However, the diagnostic criteria, in particular for oligoastrocytoma, are highly subjective. The aim of our study was to establish genetic profiles for diffuse gliomas and to estimate their predictive impact. In this study, we screened 360 World Health Organization grade II gliomas for mutations in the IDH1, IDH2, and TP53 genes and for 1p/19q loss and correlated these with clinical outcome. Most tumors (86%) were characterized genetically by TP53 mutation plus IDH1/2 mutation (32%), 1p/19q loss plus IDH1/2 mutation (37%), or IDH1/2 mutation only (17%). TP53 mutations only or 1p/19q loss only was rare (2 and 3%, respectively). The median survival of patients with TP53 mutation ± IDH1/2 mutation was significantly shorter than that of patients with 1p/19q loss ± IDH1/2 mutation (51.8 months vs. 58.7 months, respectively; P = 0.0037). Multivariate analysis with adjustment for age and treatment confirmed these results (P = 0.0087) and also revealed that TP53 mutation is a significant prognostic marker for shorter survival (P = 0.0005) and 1p/19q loss for longer survival (P = 0.0002), while IDH1/2 mutations are not prognostic (P = 0.8737). The molecular classification on the basis of IDH1/2 mutation, TP53 mutation, and 1p/19q loss has power similar to histological classification and avoids the ambiguity inherent to the diagnosis of oligoastrocytoma.

Pixel-based comparison of spinal cord MR diffusion anisotropy with axon packing parameters

Water diffusion in nerve fibers is strongly influenced by axon architecture. In this study, fractional diffusion anisotropy and transverse and longitudinal diffusion coefficients were measured in excised human cervical spinal cord with MR line-scan diffusion imaging, at 625 microm in-plane resolution and 3 mm slice thickness. A pixel-based comparison of fractional diffusion anisotropy, transverse diffusion coefficient, and longitudinal diffusion coefficient data with axon packing parameters derived from corresponding stained histological sections was performed for four slices. The axon packing parameters, axon density, axon area-fraction, and average axon size for entire specimen cross-sections were calculated by computerized segmentation of optical microscopy data obtained at 0.53 microm resolution. Salient features could be recognized on fractional diffusion anisotropy, transverse diffusion coefficient, axon density, axon area fraction, and average axon size maps. For white matter regions only, the average correlation coefficients for fractional diffusion anisotropy compared to histology-based parameters axon density and axon area fraction were 0.37 and 0.21, respectively. For transverse diffusion coefficient compared to axon density and axon area fraction, they were -0.40 and -0.36, and for longitudinal diffusion coefficient compared to axon density and axon area fraction, -0.14 and -0.30. All average correlation coefficients for average axon size were low. Correlation coefficients for collectively analyzed white and gray matter regions were significantly higher than correlation coefficients derived from analysis of white matter regions only.

Cerebrospinal fluid cytology in patients with ependymoma: a bi-institutional retrospective study

BACKGROUND

Ependymoma cells are known to occasionally exfoliate into cerebrospinal fluid (CSF). However, the frequency of CSF involvement in patients with ependymoma is unclear, and to the authors' knowledge the cytomorphologic features of the tumor cells have not been described in detail to date. In this study, the CSF findings in patients with ependymal neoplasms are summarized and the cytomorphologic features of ependymoma, including its variants, are illustrated.

METHODS

A search of the pathology databases of 2 medical centers was performed to identify all patients with a histologic diagnosis of ependymoma in whom CSF samples were examined. Slides from CSF samples originally reported as atypical, suspicious, or positive were reviewed and the cytomorphologic features assessed. Follow-up included a review of the medical records and histologic correlation.

RESULTS

In all, 177 patients with a diagnosis of ependymoma were identified. Of these, 48 had a total of 94 cytologic preparations of CSF. Positive, suspicious, atypical, negative, and nondiagnostic results were noted in 6.4%, 5.3%, 4.3%, 79.7%, and 4.3%, respectively, of the specimens. The detection rate of tumor cells in CSF was 6.7% in 15 adults and 21.2% in 33 children, with an overall rate of 16.7%. Of the 8 patients with positive and/or suspicious diagnoses, 5 ependymomas exhibited anaplastic features and 1 tumor was a myxopapillary ependymoma. The positive samples were usually hypercellular, with cohesive epithelioid cells; long cytoplasmic processes resembling bipolar tanycytes were observed in the tanycytic variant of ependymoma.

CONCLUSIONS

Exfoliated cells from ependymomas are recognizable in CSF samples, especially in patients with myxopapillary tumors and tumors with anaplastic features.

Outcome of pediatric pineoblastoma after surgery, radiation and chemotherapy

INTRODUCTION

Pineoblastomas are a category of supratentorial primitive neuroectodermal tumors (sPNETs) occurring in the pineal gland; some studies support the impression that patients with pineoblastomas have a worse prognosis than those with other sPNETs.

METHODS

We reviewed the medical records and tissue sections of all patients with the diagnosis of pineoblastoma that were treated at the Dana-Farber Cancer Institute/Children's Hospital Boston Pediatric Brain Tumor Program between 1986 and 2005.

RESULTS

Thirteen patients with the pathologic diagnosis of pineoblastoma were treated at our Hospital; 11 of these cases had complete records suitable for study. The median age was 8 years 8 months (5 F, 6 M). Surgical, radiation and chemotherapeutic regimens varied from case to case. Three patients had gross total resection and are alive and free of disease, versus four of eight with subtotal resection or biopsy only. Patients who received CSI and multi-agent chemotherapy had improved overall survival.

CONCLUSIONS

Seven of eleven patients with pineoblastoma are currently alive and free of disease, reflecting an improved outcome and longer survival than previously appreciated. Gross total surgical resection appeared to correlate with improved survival, as did treatment with craniospinal irradiation and multi-agent chemotherapy. Further study of this group of patients as a distinct diagnostic entity will be necessary to determine optimal therapy.

The 1p-encoded protein stathmin and resistance of malignant gliomas to nitrosoureas

BACKGROUND

Malignant gliomas are generally resistant to all conventional therapies. Notable exceptions are anaplastic oligodendrogliomas with loss of heterozygosity on chromosome 1p (1p+/-). Patients with 1p+/- anaplastic oligodendroglioma frequently respond to procarbazine, 1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea, and vincristine. Because the underlying biologic basis for this clinical finding is unclear, we evaluated differentially expressed 1p-encoded proteins in 1p+/- and 1p+/+ malignant glioma cell lines and then examined whether their expression was associated with outcome of patients with anaplastic oligodendroglioma.

METHODS

We used a comparative proteomic screen of A172 (1p+/-) and U251 (1p+/+) malignant glioma cell lines to identify differentially expressed 1p-encoded proteins, including stathmin, a microtubule-associated protein. 1p+/- and 1p+/+ anaplastic oligodendroglioma specimens from 24 patients were assessed for stathmin expression by immunohistochemistry. The relationship between stathmin expression and clinical outcome was assessed with Kaplan-Meier analyses. RNA inhibition and cDNA transfection experiments tested effects of stathmin under- and overexpression, respectively, on the in vitro and in vivo resistance of malignant glioma cells to treatment with nitrosourea. For in vivo resistance studies, 36 mice with intracranial and 16 mice with subcutaneous xenograft tumor implants were used (one tumor per mouse). Flow cytometry was used for cell cycle analysis. Immunoblotting was used to assess protein expression. All statistical tests were two-sided.

RESULTS

Decreased stathmin expression in tumors was statistically significantly associated with loss of heterozygosity in 1p (P<.001) and increased recurrence-free survival (P<.001). The median recurrence-free survival times for patients with tumors expressing low, intermediate, or high stathmin levels were 45 months (95% confidence interval [CI] = 0 to 90 months), 17 months (95% CI = 10.6 to 23.4 months), and 6 months (95% CI = 1.7 to 10.3 months), respectively. Expression of stathmin was inversely associated with overall survival of nitrosourea-treated mice carrying xenograft tumors. Median survival of mice with stathmin+/- tumors was 95 days (95% CI = 68.7 to 121.3 days) and that of mice with stathmin+/+ tumors was 64 days (95% CI = 58.2 to 69.8 days) (difference = 31 days, 95% CI = 4.1 to 57.9 days; P<.001, log-rank test). Nitrosoureas induced mitotic arrest in malignant glioma cells, and this effect was greater in cells with decreased stathmin expression.

CONCLUSIONS

Loss of heterozygosity for the stathmin gene may be associated with improved outcomes of patients with 1p+/- anaplastic oligodendroglioma tumors.

Predicting survival of children with CNS tumors using proton magnetic resonance spectroscopic imaging biomarkers

Using brain proton magnetic resonance spectroscopic imaging (MRSI) in children with central nervous system (CNS) tumors, we tested the hypothesis that combining information from biologically important metabolites, at diagnosis and prior to treatment, would improve prediction of survival. We evaluated brain proton MRSI exams in 76 children (median age at diagnosis: 74 months) with brain tumors. Important biomarkers, choline-containing compounds (Cho), N-acetylaspartate (NAA), total creatine (tCr), lipids and/or lactate (L), were measured at the "highest Cho region" and normalized to the tCr of surrounding healthy tissue. Neuropathological grading was performed using World Health Organization (WHO) criteria. Fifty-eight of 76 (76%) patients were alive at the end of the study period. The mean survival time for all subjects was 52 months. Univariate analysis demonstrated that Cho, L, Cho/NAA and tumor grade differed significantly between survivors and non-survivors (P< or =0.05). Multiple logistic regression and stepwise multivariate Cox regression indicated that Cho + 0.1L was the only independent predictor of survival (likelihood ratio test = 10.27, P<0.001; Cox regression, P=0.004). The combined index Cho + 0.1L was more accurate and more specific predictor than Cho or Cho/NAA. Accuracy and specificity for Cho + 0.1L were 80% and 86%, respectively. We conclude that brain proton MRSI biomarkers predict survival of children with CNS tumors better than does standard histopathology. More accurate prediction using this non-invasive technique represents an important advance and may suggest more appropriate therapy, especially when diagnostic biopsy is not feasible.

Intramedullary neuroma of the cervicomedullary junction. Case report

Neuromas typically arise in the peripheral nervous system in response to traumatic injury at the site of partial or complete nerve transection as new axons from the proximal nerve stump sprout to reinnervate the distal segment. In rare cases neuromas have also been described as intramedullary spinal cord lesions. These lesions have been identified as incidental autopsy findings in association with prior trauma and cervical spondylosis, multiple sclerosis, spinal tumors, and syringomyelia. The authors report the case of a 50-year-old man who had been involved in a motor vehicle accident, during which his car was struck from behind as it was stationary at an intersection, more than 5 years before presentation. A workup for syncopal and presyncopal episodes involved magnetic resonance imaging that revealed a 1.1-cm lesion at the cervicomedullary junction (CMJ). The imaging features of the lesion raised the question of an ependymoma or subependymoma. The lesion was excised, and examination of the tissue demonstrated a neuroma with haphazardly arranged interlacing bundles of axons ensheathed by Schwann cells with interfascicular regions of reactive glial cells and Rosenthal fibers, consistent with those present after traumatic injury. This case may represent the first true traumatic intramedullary neuroma of the CMJ diagnosed in a living patient and treated surgically.

XRCC4 suppresses medulloblastomas with recurrent translocations in p53-deficient mice

Inactivation of the XRCC4 nonhomologous end-joining factor in the mouse germ line leads to embryonic lethality, in association with apoptosis of newly generated, postmitotic neurons. We now show that conditional inactivation of the XRCC4 in nestin-expressing neuronal progenitor cells, although leading to no obvious phenotype in a WT background, leads to early onset of neuronally differentiated medulloblastomas (MBs) in a p53-deficient background. A substantial proportion of the XRCC4/p53-deficient MBs have high-level N-myc gene amplification, often intrachromosomally in the context of complex translocations or other alterations of chromosome 12, on which N-myc resides, or extrachromosomally within double minutes. In addition, most XRCC4/p53-deficient MBs harbor clonal translocations of chromosome 13, which frequently involve chromosome 6 as a partner. One copy of the patched gene (Ptc), which lies on chromosome 13, was deleted in all tested XRCC4/p53-deficient MBs in the context of translocations or interstitial deletions. In addition, Cyclin D2, a chromosome 6 gene, was amplified in a subset of tumors. Notably, amplification of Myc-family or Cyclin D2 genes and deletion of Ptc also have been observed in human MBs. We therefore conclude that, in neuronal cells of mice, the nonhomologous end-joining pathway plays a critical role in suppressing genomic instability that, in a p53-deficient background, routinely contributes to genesis of MBs with recurrent chromosomal alterations.

Collateral nerve fibers in human spinal cord: Visualization with magnetic resonance diffusion tensor imaging

Diffusion tensor magnetic resonance imaging provides structural information about nerve fiber tissue. The first eigenvector of the diffusion tensor is aligned with the nerve fibers, i.e., longitudinally in the spinal cord. The underlying hypothesis of this study is that the presence of collateral nerve fibers running orthogonal to the longitudinal fibers results in an orderly arrangement of the second eigenvectors. Magnetic resonance diffusion tensor scans were performed with line scan diffusion imaging on a clinical MR scanner. Axial sections were scanned in a human cervical spinal cord specimen at 625 microm resolution and the cervical spinal cord of four normal volunteers at 1250 microm resolution. The spinal cord specimen was fixed and stained for later light microscopy of the collateral fiber architecture at 0.53 microm resolution. Diffusion measured by MR was found to be anisotropic for both white and gray matter areas of the spinal cord specimen; the average fractional anisotropy (FA) was 0.63 +/- 0.09 (diffusion eigenvalues lambda1 0.38 +/- 0.05 micros/mm2, lambda2 0.14 +/- 0.03 micros/mm2, lambda3 0.10 +/- 0.03 micros/mm2) in white matter and 0.27 +/- 0.04 (lambda1 0.36 +/- 0.04 micros/mm2, lambda2 0.28 +/- 0.03 micros/mm2, lambda3 0.21 +/- 0.04 micros/mm2 in gray matter. The normal-volunteer FA values were similar, i.e., 0.66 +/- 0.04 (lambda1 1.66 +/- 0.14 micros/mm2, lambda2 0.55 +/- 0.02 micros/mm2, lambda3 0.40 +/- 0.01 micros/mm2) in white matter and 0.35 +/- 0.03 (lambda1 1.14 +/- 0.07 micros/mm2, lambda2 0.70 +/- 0.03 micros/mm2, lambda3 0.58 +/- 0.02 micros/mm2) in gray matter. The first eigenvector pointed, as expected, in the longitudinal direction. The second eigenvector directions exhibited a striking arrangement, consistent with the distribution of interconnecting collateral nerve fibers discerned on the histology section. This finding was confirmed for the specimen by quantitative pixel-wise comparison of second eigenvector directions and collateral fiber directions assessed on light microscopy image data. Diffusion tensor MRI can reveal non-invasively and in great detail the intricate fiber architecture of the human spinal cord.

Characterization of lymphocytic infiltrates in progressive multifocal leukoencephalopathy: Co-localization of CD8+T cells with JCV-infected glial cells

We characterized inflammatory infiltrates in archival brain biopsy and autopsy samples from 26 HIV(+) and 20 HIV(-) patients with progressive multifocal leukoencephalopathy (PML). The predominant inflammatory cells were CD8(+) T lymphocytes. We defined CD8(+) T cell distribution with regard to JCV-infected glial cells, PML lesions and the extent of demyelination. In most samples from either HIV(+) and HIV(-) patients, we found positive correlations between the parenchymal CD8(+) T cells and JCV-infected glial cells and conversely, negative correlations between the perivascular CD8(+) T cells and JCV-infected glial cells in the surrounding brain. Most of these correlations remained significant after accounting for the degree of demyelination and location of the cells relative to lesions. Moreover, high numbers of CD8(+) T cells were found within and at the border of active PML lesions. These results suggest that CD8(+) T cells are primarily associated with JCV-infected glial cells in most PML cases and that an active ongoing recruitment of CD8(+) T cells and possibly viral antigen-specific retention could occur. These observations are discussed in the context of the recent evidence of PML in multiple sclerosis and Crohn's patients treated with natalizumab, underscoring the role of CD8(+) T lymphocytes in continued immunosurveillance of the CNS.

Lyme Meningoradiculitis and Myositis after Allogeneic Hematopoietic Stem Cell Transplantation

We describe a patient with a history of allogeneic hematopoietic stem cell transplantation complicated by chronic graft-versus-host disease who developed painful meningoradiculitis and myositis due to Lyme borreliosis. To our knowledge, this is the first report of such an infection occurring after allogeneic hematopoietic stem cell transplantation in the United States.

Noninvasive magnetic resonance spectroscopic imaging biomarkers to predict the clinical grade of pediatric brain tumors

The diagnosis and therapy of childhood brain tumors, most of which are low grade, can be complicated because of their frequent adjacent location to crucial structures, which limits diagnostic biopsy. Also, although new prognostic biomarkers identified by molecular analysis or DNA microarray gene profiling are promising, they too depend on invasive biopsy. Here, we test the hypothesis that combining information from biologically important intracellular molecules (biomarkers), noninvasively obtained by proton magnetic resonance spectroscopic imaging, will increase the diagnostic accuracy in determining the clinical grade of pediatric brain tumors. We evaluate the proton magnetic resonance spectroscopic imaging exams for 66 children with brain tumors. The intracellular biomarkers for choline-containing compounds (Cho), N-acetylaspartate, total creatine, and lipids and/or lactate were measured at the highest Cho region and normalized to the surrounding healthy tissue total creatine. Neuropathological grading was done with WHO criteria. Normalized Cho and lipids and/or lactate were elevated in high-grade (n = 23) versus low-grade (n = 43) tumors, which multiple logistic regression confirmed are independent predictors of tumor grade (for Cho, odds ratio 24.8, P < 0.001; and for lipids and/or lactate, odds ratio 4.4, P < 0.001). A linear combination of normalized Cho and lipids and/or lactate that maximizes diagnostic accuracy was calculated by maximizing the area under the receiver operating characteristic curve. Proton magnetic resonance spectroscopic imaging, although not a proxy for histology, provides noninvasive, in vivo biomarkers for predicting clinical grades of pediatric brain tumors.

Adverse cerebrovascular effects of intraarterial CO2 injections: development of an in vitro/in vivo model for assessment of gas-based toxicity

PURPOSE

To assess whether and how CO(2) can cause ischemic injury in the central nervous system after internal carotid artery injection.

MATERIALS AND METHODS

In 14 adult pigs, both internal carotid arteries were catheterized via a transfemoral approach. One carotid artery served as control and the other was injected via a prototype gas injector with defined volumes and pressures of gas. Effects were assessed by clinical observation, repeated magnetic resonance (MR) imaging, histopathology, and vital staining. An in vitro flow circuit was used to model injection parameters.

RESULTS

Single injections of CO(2) did not produce persistent clinical symptomatology. In vitro conditions were created in which bubbles adhered to the tubing of the circuit, creating functional stenoses, or coalesced into larger bubbles that became trapped, thereby reducing flow and augmenting potential embologenic effects of subsequent injections. With in vitro-derived dual injection parameters, seven pigs underwent two sequential injections of CO(2). All did well after the first injections, but all had adverse effects after the second injections, including involuntary tonic-clonic muscular movements, cardiopulmonary arrest, recurrent intractable seizure activity during recovery, hemorrhagic venous infarcts on gross and histopathologic examination, and blood-brain barrier breakdown on vital staining. MR imaging was not sensitive even after symptomatic intraarterial air injection.

CONCLUSIONS

Absence of adverse effects after single bolus injections in pigs does not prove the safety of intracranial CO(2) injections in human patients. Considering the possible deleterious effects of repeat intravascular injections in the highly sensitive system of the brain, it may be prudent for clinical application at other approved sites to let time pass between boluses sufficient to permit absorption of wall-adherent and coalescent bubbles that could cause gas embolic events.

Transcriptional therapy with the histone deacetylase inhibitor trichostatin A ameliorates experimental autoimmune encephalomyelitis

We demonstrate that the histone deacetylase (HDAC) inhibitor drug trichostatin A (TSA) reduces spinal cord inflammation, demyelination, neuronal and axonal loss and ameliorates disability in the relapsing phase of experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS). TSA up-regulates antioxidant, anti-excitotoxicity and pro-neuronal growth and differentiation mRNAs. TSA also inhibits caspase activation and down-regulates gene targets of the pro-apoptotic E2F transcription factor pathway. In splenocytes, TSA reduces chemotactic, pro-Th1 and pro-proliferative mRNAs. A transcriptional imbalance in MS may contribute to immune dysregulation and neurodegeneration, and we identify HDAC inhibition as a transcriptional intervention to ameliorate this imbalance.

Proliferative Potential of Human Astrocytes

Although a number of studies have demonstrated proliferation of nonneoplastic astrocytes in experimental animal models, the proliferative potential of human astrocytes has not been well defined. Using double-label immunohistochemistry, we identified proliferating cells with the proliferation marker MIB-1 and astrocytes with glial fibrillary acidic protein staining in human biopsy and autopsy tissue. MIB-1 labeling of astrocytes was monitored in a variety of conditions containing significant numbers of reactive astrocytes, including infections, arteriovenous malformations, demyelinating lesions, metastatic tumors, and long-standing gliosis. Twenty-nine of a total of 54 cases showed no evidence of astrocyte-specific MIB-1 labeling despite prominent reactive changes. An average proliferation rate of 0.9% was present in the remaining 25 cases. Labeling indices were highest in infectious conditions and acute demyelinating lesions. We also examined astrocyte proliferation in 5 cases of progressive multifocal leukoencephalopathy. Astrocytic labeling indices were notably elevated in these cases, with an average labeling index of 5.8%. We conclude that low, but appreciable, astrocytic proliferation may occur in nonneoplastic human astrocytes. These findings have implications for astrocyte function in the normal and disease states and for the diagnostic distinction between reactive lesions and low-grade astrocytic neoplasms.

Neurologic and histopathologic evaluation after high-volume intrathecal amitriptyline

BACKGROUND AND OBJECTIVES

Accumulating evidence indicates that amitriptyline decreases pain sensation when administered orally, intraperitoneally, or for sciatic nerve block. Previous reports of intrathecal administration of amitriptyline have yielded inconsistent results. The failure of amitriptyline to provide antinociception may partly be related to its high logP (octanol-water partition coefficient) and consequent poor spread within the cerebrospinal fluid. We evaluated spinal block after various concentrations of amitriptyline administered intrathecally in a fixed high volume.

METHODS

We administered 100 microL of 5, 10, 15.9 (0.5%), 25, 50, or 100 mmol/L amitriptyline hydrochloride solution or 100 microL of 15.4 mmol/L (0.5%) bupivacaine hydrochloride solution intrathecally to rats. The neurologic deficit was evaluated by antinociceptive, motor, and proprioceptive responses, and the spinal cord was examined for histopathologic changes.

RESULTS

Doses of 100 microL amitriptyline at 15.9 mmol/L (0.5%) and 25 mmol/L produced longer complete nerve block than did bupivacaine at 15.4 mmol/L (0.5%); 5 and 10 mmol/L amitriptyline produced only partial nerve block. However, with 100 microL intrathecal amitriptyline at 50 and 100 mmol/L, many rats did not fully recover from spinal block. Severe axonal degeneration, myelin breakdown, and replacement of neuronal structures by vacuoles were seen in the spinal root section of animals injected with concentrations higher than 25 mmol/L amitriptyline.

CONCLUSIONS

At lower doses, intrathecal injection of high volumes of amitriptyline results in long-acting spinal block. At higher doses, intrathecal amitriptyline results in irreversible neurologic deficit. Therefore, we do not recommend the use of intrathecal amitriptyline because of a very low therapeutic index.

Local Anesthetic Properties of a Novel Derivative, N-Methyl Doxepin, Versus Doxepin and Bupivacaine

Among various tricyclic antidepressants, doxepin and amitriptyline are also long-acting local anesthetics. We synthesized a new compound, N-methyl doxepin, and investigated whether this derivative possesses local anesthetic properties. N-methyl doxepin and doxepin were tested in a rat sciatic nerve model at 2.5, 5.0, and 10 mM. Proprioceptive, motor, and nociceptive blockade were evaluated and compared with those induced by 0.5% bupivacaine. Block of Na(+) channels by N-methyl doxepin and doxepin was assessed in cultured pituitary tumor cells under voltage clamp conditions. N-methyl doxepin elicited complete nociceptive blockade that generally lasted longer than that caused by doxepin (e.g., approximately 7.4 h versus 5.3 h at 10 mM). Significant differences were observed for full recovery of function at all concentrations and for the duration of complete blockade except at 2.5 mM. Bupivacaine at 0.5% (15.4 mM) was less effective in producing complete blockade (approximately 1.5 h) than N-methyl doxepin and doxepin. Both doxepin and N-methyl doxepin were potent Na(+) channel blockers, although N-methyl doxepin displayed a slower wash-in rate. No morphological alterations were detected in cross-sectioned sciatic nerve specimens with these three drugs. We conclude that N-methyl doxepin is a potent Na(+) channel blocker and a long-acting local anesthetic for rat sciatic nerve blockade.

IMPLICATIONS

N-methyl doxepin and doxepin are both potent Na(+) channel blockers; they elicit rat sciatic nerve block lasting longer than that induced by bupivacaine and seem to be nontoxic to peripheral nerves at concentrations up to 10 mM.

Cytologic features of pilocytic astrocytoma in cerebrospinal fluid specimens

OBJECTIVE

To illustrate the cytomorphologic features of pilocytic astrocytoma (PA) in cerebrospinal fluid (CSF) samples.

STUDY DESIGN

A search of records from 1965 to 2001 was performed to identify all patients with a diagnosis of PA in whom CSF samples were examined. Slides from CSF samples originally reported as atypical, suspicious or positive were reviewed and the cytomorphologic features assessed.

RESULTS

Two hundred ninety-three patients with a diagnosis of PA were identified. Of these, 44 had a total of 65 cytologic preparations of CSF. In 34 patients (77.2%) the CSF cytology was negative, in 5 (11.4%) either atypical or suspicious, and in 5 (11.4%) positive for neoplastic cells. The tumors in the 5 positive cases arose in the cerebellar hemispheres (2), cerebellar vermis (1), thalamus (1) and tectum with extension into the fourth ventricle (1). All positive samples were hypercellular, with an average of 5 cell clusters per case (range, 3-11). The clusters were composed of cohesive epithelioid cells with a mean of 8 cells per cluster. In addition, some cases had scattered, isolated, single cells. These single neoplastic cells had prominent, hairlike cytoplasmic processes. The cells in clusters appeared epithelioid, with oval nuclei, mild nuclear pleomorphism, finely or slightly coarsely granular chromatin and cobweblike cytoplasm.

CONCLUSION

The cytomorphologic features of PAs recapitulate their histologic characteristics. The tumor cells are recognizable in CSF samples and readily distinguishable from histiocytes and ependymal cells.

Paediatric mononeuritis multiplex: a report of three cases and review of the literature

Mononeuritis multiplex results from disease processes causing multifocal injury to the peripheral nerves, with or without involvement of one or more cranial nerves. Most reported cases of paediatric mononeuritis multiplex have been related to autoimmune disorders. We present clinical and neurophysiologic findings in three cases of multiple mononeuropathy occurring in adolescence, with onset at ages 16, 17 and 13 years. Two of these cases were related to systemic vasculitis, one possibly representing a paediatric case of non-systemic vasculitis. Sural nerve biopsy confirmed the diagnosis of vasculitis in one patient with systemic lupus erythematosus, but was non-diagnostic in another case. Mononeuritis multiplex is an extremely uncommon form of acquired peripheral neuropathy in childhood. We discuss the differential diagnosis and review previous descriptions of this rare condition.