Prognostic Value of Preoperative MRI Metrics for Diffuse Lower-Grade Glioma Molecular Subtypes

BACKGROUND AND PURPOSE

Despite the improved prognostic relevance of the 2016 WHO molecular-based classification of lower-grade gliomas, variability in clinical outcome persists within existing molecular subtypes. Our aim was to determine prognostically significant metrics on preoperative MR imaging for lower-grade gliomas within currently defined molecular categories.

MATERIALS AND METHODS

We undertook a retrospective analysis of 306 patients with lower-grade gliomas accrued from an institutional data base and The Cancer Genome Atlas. Two neuroradiologists in consensus analyzed preoperative MRIs of each lower-grade glioma to determine the following: tumor size, tumor location, number of involved lobes, corpus callosum involvement, hydrocephalus, midline shift, eloquent cortex involvement, ependymal extension, margins, contrast enhancement, and necrosis. Adjusted hazard ratios determined the association between MR imaging metrics and overall survival per molecular subtype, after adjustment for patient age, patient sex, World Health Organization grade, and surgical resection status.

RESULTS

For isocitrate dehydrogenase (IDH) wild-type lower-grade gliomas, tumor size (hazard ratio, 3.82; 95% CI, 1.94-7.75; P < .001), number of involved lobes (hazard ratio, 1.70; 95% CI, 1.28-2.27; P < .001), hydrocephalus (hazard ratio, 4.43; 95% CI, 1.12-17.54; P = .034), midline shift (hazard ratio, 1.16; 95% CI, 1.03-1.30; P = .013), margins (P = .031), and contrast enhancement (hazard ratio, 0.34; 95% CI, 0.13-0.90; P = .030) were associated with overall survival. For IDH-mutant 1p/19q-codeleted lower-grade gliomas, tumor size (hazard ratio, 2.85; 95% CI, 1.06-7.70; P = .039) and ependymal extension (hazard ratio, 6.34; 95% CI, 1.07-37.59; P = .042) were associated with overall survival.

CONCLUSIONS

MR imaging metrics offers prognostic information for patients with lower-grade gliomas within molecularly defined classes, with the greatest prognostic value for IDH wild-type lower-grade gliomas.

Molecular Subtype Classification in Lower-Grade Glioma with Accelerated DTI

BACKGROUND AND PURPOSE

Image-based classification of lower-grade glioma molecular subtypes has substantial prognostic value. Diffusion tensor imaging has shown promise in lower-grade glioma subtyping but currently requires lengthy, nonstandard acquisitions. Our goal was to investigate lower-grade glioma classification using a machine learning technique that estimates fractional anisotropy from accelerated diffusion MR imaging scans containing only 3 diffusion-encoding directions.

MATERIALS AND METHODS

Patients with lower-grade gliomas (n = 41) (World Health Organization grades II and III) with known isocitrate dehydrogenase (IDH) mutation and 1p/19q codeletion status were imaged preoperatively with DTI. Whole-tumor volumes were autodelineated using conventional anatomic MR imaging sequences. In addition to conventional ADC and fractional anisotropy reconstructions, fractional anisotropy estimates were computed from 3-direction DTI subsets using DiffNet, a neural network that directly computes fractional anisotropy from raw DTI data. Differences in whole-tumor ADC, fractional anisotropy, and estimated fractional anisotropy were assessed between IDH-wild-type and IDH-mutant lower-grade gliomas with and without 1p/19q codeletion. Multivariate classification models were developed using whole-tumor histogram and texture features from ADC, ADC + fractional anisotropy, and ADC + estimated fractional anisotropy to identify the added value provided by fractional anisotropy and estimated fractional anisotropy.

RESULTS

ADC (P = .008), fractional anisotropy (P < .001), and estimated fractional anisotropy (P < .001) significantly differed between IDH-wild-type and IDH-mutant lower-grade gliomas. ADC (P < .001) significantly differed between IDH-mutant gliomas with and without codeletion. ADC-only multivariate classification predicted IDH mutation status with an area under the curve of 0.81 and codeletion status with an area under the curve of 0.83. Performance improved to area under the curve = 0.90/0.94 for the ADC + fractional anisotropy classification and to area under the curve = 0.89/0.89 for the ADC + estimated fractional anisotropy classification.

CONCLUSIONS

Fractional anisotropy estimates made from accelerated 3-direction DTI scans add value in classifying lower-grade glioma molecular status.

Extent of Surgical Resection in Lower-Grade Gliomas: Differential Impact Based on Molecular Subtype

BACKGROUND AND PURPOSE

Diffuse lower-grade gliomas are classified into prognostically meaningful molecular subtypes. We aimed to determine the impact of surgical resection on overall survival in lower-grade glioma molecular subtypes.

MATERIALS AND METHODS

For 172 patients with lower-grade gliomas (World Health Organization grade II or III), pre- and postsurgical glioma volumes were determined using a semiautomated segmentation software based on FLAIR or T2-weighted MR imaging sequences. The association of pre- and postsurgical glioma volume and the percentage of glioma resection with overall survival was determined for the entire cohort and separately for lower-grade glioma molecular subtypes based on isocitrate dehydrogenase (IDH) and 1p/19q status, after adjustment for age, sex, World Health Organization grade, chemotherapy administration, and radiation therapy administration.

RESULTS

For the entire cohort, postsurgical glioma volume (hazard ratio, 1.80; 95% CI, 1.18-2.75; P = .006) and the percentage of resection (hazard ratio, 3.22; 95% CI, 1.79-5.82; P < .001) were associated with overall survival. For IDH-mutant 1p/19q-codeleted oligodendrogliomas, the percentage of resection (hazard ratio, 6.69; 95% CI, 1.57-28.46; P = .01) was associated with overall survival. For IDH-mutant 1p/19q-noncodeleted astrocytomas, presurgical glioma volume (hazard ratio, 3.20; 95% CI, 1.22-8.39; P = .018), postsurgical glioma volume (hazard ratio, 2.33; 95% CI, 1.32-4.12; P = .004), and percentage of resection (hazard ratio, 4.34; 95% CI, 1.74-10.81; P = .002) were associated with overall survival. For IDH-wild-type lower-grade gliomas, pre-/postsurgical glioma volume and percentage of resection were not associated with overall survival.

CONCLUSIONS

The extent of surgical resection has a differential survival impact in patients with lower-grade gliomas based on their molecular subtype. IDH-mutant lower-grade gliomas benefit from a greater extent of surgical resection, with the strongest impact observed for IDH-mutant 1p/19q-noncodeleted astrocytomas.

Neuroimaging-Based Classification Algorithm for Predicting 1p/19q-Codeletion Status in IDH-Mutant Lower Grade Gliomas

BACKGROUND AND PURPOSE

Isocitrate dehydrogenase (IDH)-mutant lower grade gliomas are classified as oligodendrogliomas or diffuse astrocytomas based on 1p/19q-codeletion status. We aimed to test and validate neuroradiologists' performances in predicting the codeletion status of IDH-mutant lower grade gliomas based on simple neuroimaging metrics.

MATERIALS AND METHODS

One hundred two IDH-mutant lower grade gliomas with preoperative MR imaging and known 1p/19q status from The Cancer Genome Atlas composed a training dataset. Two neuroradiologists in consensus analyzed the training dataset for various imaging features: tumor texture, margins, cortical infiltration, T2-FLAIR mismatch, tumor cyst, T2* susceptibility, hydrocephalus, midline shift, maximum dimension, primary lobe, necrosis, enhancement, edema, and gliomatosis. Statistical analysis of the training data produced a multivariate classification model for codeletion prediction based on a subset of MR imaging features and patient age. To validate the classification model, 2 different independent neuroradiologists analyzed a separate cohort of 106 institutional IDH-mutant lower grade gliomas.

RESULTS

Training dataset analysis produced a 2-step classification algorithm with 86.3% codeletion prediction accuracy, based on the following: 1) the presence of the T2-FLAIR mismatch sign, which was 100% predictive of noncodeleted lower grade gliomas, (n = 21); and 2) a logistic regression model based on texture, patient age, T2* susceptibility, primary lobe, and hydrocephalus. Independent validation of the classification algorithm rendered codeletion prediction accuracies of 81.1% and 79.2% in 2 independent readers. The metrics used in the algorithm were associated with moderate-substantial interreader agreement (κ = 0.56-0.79).

CONCLUSIONS

We have validated a classification algorithm based on simple, reproducible neuroimaging metrics and patient age that demonstrates a moderate prediction accuracy of 1p/19q-codeletion status among IDH-mutant lower grade gliomas.

Influência do Antioxidante Resveratrol nas Propriedades Físicas e Mecânicas do Esmalte Clareado

O objetivo deste estudo foi avaliar o efeito do antioxidante resveratrol associado ao peróxido de hidrogênio a 38%. 80 terceiros molares foram divididos em 8 grupos (n10): SC – Sem clareamento em 24h, SC21 – sem clareamento em 21 dias, SCR – Sem clareamento e com resveratrol em 24h, SCR21 – Sem clareamento e com resveratrol em 21dias, C – com clareamento sem resveratrol em 24h, C21 – com clareamento sem resveratrol em 21 dias, CR – com clareamento e com resveratrol em 24h, CR21 – com clareamento e com resveratrol em 21dias. Nos grupos com resveratrol, o mesmo foi aplicado por 1 min após o clareamento. As amostras foram submetidas aos testes de microdureza Knoop, rugosidade, microcisalhamento e avaliação de cor (e). Os dados foram submetidos   a ANOVA e ao teste de Tukey (5%). Foi observada redução (p<0.05) de dureza somente para os grupos com resveratrol (SCR - 256±51, SCR21 - 276±54, CR - 272±42 e CR21 - 258±49). Foi observado diferença (p<0.05) na rugosidade somente no grupo C (0,13±0,05). Os grupos com resveratrol tiveram redução nos valores em MPa (p<0.05) em 24h (SCR – 4,00±1,53, CR – 3,97±4,69), entretanto aumento em 21d (SCR21 – 8,02±2,80, CR – 10,82±4,69) (p>0.05). Houve variação de e (p<0.05) somente para os grupos clareados. Houve uma diminuição nas falhas mistas para os grupos com resveratrol após 21dias e uma diminuição para os demais. O resveratrol apresentou um efetivo potencial antioxidante sem influenciar na alteração de cor gerado pelo clareamento.Palavras-chave: Antioxidantes. Microcisalhamento. Clareamento Dental.

Avaliação in vivo da Rugosidade do Esmalte após Remoção de Braquetes Colados com Diferentes Materiais Cimentantes

O objetivo foi avaliar a rugosidade superficial do esmalte dentário utilizando rugosímetro antes e após polimento com diferentes materiais cimentantes. Quinze pacientes ortodônticos foram selecionados para o estudo e réplicas dos dentes 11 e 21 foram confeccionadas com resina epóxica. Nos dentes de um lado da boca foram colados braquetes com resina composta (Transbond XT [T] n 15). Dentes do outro lado foram colados com cimento de ionômero de vidro modificado por resina (Vitremer [V] n 15). Todos os dentes foram acabados e polidos com discos de óxido de alumínio (Sof-Lex). Na conclusão do tratamento ortodôntico, os braquetes foram removidos e réplicas dentárias após o polimento dos dentes foram obtidas. Três mensurações de rugosidade superficial foram efetuadas, e uma média para cada réplica dental foi calculada. Os dados foram avaliados estatisticamente rugosidade pela análise- medidas repetidas de variância. Após a remoção dos cimentos com os discos de óxido de alumínio, nos dois grupos estudados   com diferentes materiais cimentantes, observou-se que a rugosidade média da superfície do esmalte (T – 0,245 V – 0,248) foi significativamente menor quando comparado com a rugosidade superficial do esmalte antes do início do tratamento (T – 0,370  V – 0,372) não houve diferença estatística entre os materiais cimentantes. O sistema de polimento de disco de óxido de alumínio proporcionou menor rugosidade superficial do esmalte comparado à rugosidade antes do início do tratamento, independentemente do material cimentante utilizado.Palavras-chave: Esmalte Dentário. Polimento Dentário. Descolagem Dentária.

Influência do Primer e Sistema Adesivo Sobre a Resistência de União do Cimento Resinoso Quimicamente Ativado à Liga Dental Co-Cr

O objetivo foi avaliar os efeitos de primers e sistemas adesivos sobre a resistência de união ao microcisalhamento do cimento resinoso quimicamente ativado à liga de Co-Cr. Setenta e dois blocos retangulares de liga metálica Co-Cr foram fabricados e pré-tratados com partículas de dióxido de alumínio (50 µm) por 15 segundos. Aplicaram-se os primers (Alloy Primer - AP ou Clearfil Ceramic Primer - CP), adesivos (Adper Scotchbond Multi-Purpose Adhesive ativado por Adper Scotchbond Multi-Purpose Adhesive Catalyst - SASC ou Primer & Bond 2.1 ativado pelo Self Cure Activator - PBCA) e subsequentemente divididos em seis grupos (SASC AP / SASC CP / SASC PBCAAP / PBCA CP / PBCA), n 12. Em seguida, foi aplicado o cimento de resina (Enforce). Os dados para os valores resistência de união foram estatisticamente avaliados por análise de variância e teste de Tukey. A resistência de união ao microcisalhamento (MPa) foi menor (p<0,001) em grupos com sistema adesivo somente (SASC- 5,02 e PBCA- 13,38) em comparação com os grupos com adição de primers Alloy Primer (AP / SASC- 15,81 e AP / PBCA- 15,36) e Ceramic Primer (CP / SASC- 16,92 e CP / PBCA- 16,30). A aplicação de primers melhora a resistência à união do cimento resinoso à liga de metal Co-Cr.Palavras-chave: Resistência ao Cisalhamento. Cimentos de Resina. Cimentação.

Bone mineral density and inflammatory bowel disease severity

Inflammatory bowel disease (IBD) is associated with low bone mineral density (BMD). In this study, the association between disease severity and BMD in patients with IBD was evaluated. Associations between BMD and the Montreal classification, disease activity and drug therapy were also tested. A cross-sectional prevalence study with a comparison group was conducted. One hundred and twenty-eight patients were evaluated: 68 patients with ulcerative colitis (UC), and 60 with Crohn's disease (CD). The control group consisted of 67 healthy subjects. All patients and controls had BMD measured and in IBD patients, current medications, hospitalization, and disease location, extent and phenotype, according to the Montreal classification, were recorded. Multiple correspondence analysis was applied to evaluate categorical variables. In the CD group, most patients were diagnosed between 17–40 years of age. Ileocolonic and non-stricturing non-penetrating disease were the most frequent disease location and behavior, respectively. In UC patients, extensive colitis was the most frequent disease location. UC and CD patients were more likely to have osteopenia than controls (OR=14.93/OR=24.38, respectively). In the CD group, male patients, perianal disease, penetrating behavior and age at diagnosis >40 years were associated with low BMD. Taking azathioprine and infliximab also seemed to be associated with osteopenia. In the UC group, we observed an association between low BMD and male patients, left colitis, corticosteroid use and hospitalization. Disease activity was not associated with osteopenia or osteoporosis in CD and UC patients. Disease severity seems to be associated with osteopenia in IBD patients.

From pituitary adenoma to pituitary neuroendocrine tumor (PitNET): an International Pituitary Pathology Club proposal

The classification of neoplasms of adenohypophysial cells is misleading because of the simplistic distinction between adenoma and carcinoma, based solely on metastatic spread and the poor reproducibility and predictive value of the definition of atypical adenomas based on the detection of mitoses or expression of Ki-67 or p53. In addition, the current classification of neoplasms of the anterior pituitary does not accurately reflect the clinical spectrum of behavior. Invasion and regrowth of proliferative lesions and persistence of hormone hypersecretion cause significant morbidity and mortality. We propose a new terminology, pituitary neuroendocrine tumor (PitNET), which is consistent with that used for other neuroendocrine neoplasms and which recognizes the highly variable impact of these tumors on patients.

Anaplastic extramedullary cervical ependymoma with leptomeningeal metastasis

We present a rare extramedullary ependymoma with diffuse spinal metastatic disease, and review the previous reports of extramedullary spinal ependymomas. Ependymomas are the most common intramedullary spinal cord tumor in adults. These tumors rarely present as extramedullary masses. We treated a 23-year-old man with a history of progressive neck, shoulder and arm pain, with sensory and motor symptoms in the C7 dermatome. MRI of the cervical spine demonstrated a ventral contrast-enhancing lesion with evidence of enhancement along the dura and spinal cord of the upper cervical spine, thoracic spine, and cauda equina. He underwent a tumor debulking procedure without complications. Following surgery, he received craniospinal radiation to treat the remaining tumor and diffuse leptomeningeal disease. The final pathology of the tumor revealed that is was a World Health Organization Grade III anaplastic ependymoma. At the 1 year follow-up, the patient had stable imaging and had returned to his preoperative functional status. Of the 19 reported patients with primary intradural, extramedullary spinal ependymomas, two had extradural components and seven had anaplastic grades. Only one tumor with an anaplastic grade resulted in metastatic disease, but without spinal recurrence. To our knowledge, this is the first report of an intradural, extramedullary spinal ependymoma with an anaplastic grade, presenting with concomitant diffuse, nodular leptomeningeal metastasis involving the upper cervical spine, thoracic spine, conus medullaris, and cauda equina. Similar to the treatment of intramedullary ependymomas with metastasis, this patient underwent an aggressive debulking procedure followed by radiation therapy to the entire neuroaxis.

Influence of different photo-activation distances on cytotoxicity of a dental adhesive model resin

AIM

This study evaluated the cytotoxicity of a dental bonding model resin (DBMR) submitted to different photo-activation distances.

METHODS

A monomer mixture based on Bis-GMA and HEMA was used to assess the cytotoxicity in a mouse fibroblast-cell line. To promote different photo-activation distances glass slides were interposed between DBMR surface and halogen light curing unit (LCU) tip. Afterwards, the specimens were immersed in RPMI culture medium for 24 h to obtain extracts. The extracts were incubated in contact with the cells for 24 h. Finally, an MTT colorimetric assay was used to assess the cytotoxicity. The cell viability data (absorbance) were analyzed by one way ANOVA followed by Tukey's test (P<0.05).

RESULTS

The light output decreased according to the increase in the number of glass slides between the halogen LCU tip and DBMR surface. Yet, the distance between the tip of the curing light system and the specimens had significant influence on the cytotoxicity. All extracts produced by groups submitted to different photo-activation distances showed cytotoxic effect after 24h of incubation.

CONCLUSION

The photo-activation distance and the interposition of glass slides between LCU tip and DBMR was shown to play an important role in the cytotoxic effect.

Trilateral retinoblastoma variant indicative of the relevance of the retinoblastoma tumor-suppressor pathway to medulloblastomas in humans

Results of recent studies have led investigators to suggest that the retinoblastoma tumor-suppressor (rb) gene plays an underappreciated role in the genesis of brain tumors. Such tumors cause significant rates of mortality in children suffering from hereditary retinoblastoma. It has been assumed that the pineal gland, which is ontogenetically related to the retina, accounts for the intracranial origin of these trilateral neoplasms. To address this issue, the authors describe an unusual trilateral retinoblastoma variant. The authors provide a detailed clinicopathological correlation by describing the case of a child with bilateral retinoblastoma who died of a medulloblastoma. The intraocular and intracranial neoplasms were characterized by performing detailed imaging, histopathological, and postmortem studies. Karyotype analysis and fluorescence in situ hybridization were used to define the chromosomal defect carried by the patient and members of her family. An insertion of the q12.3q21.3 segment of chromosome 13 into chromosome 18 at band q23 was identified in members of the patient's family. This translocation was unbalanced in the proband. The intraocular and cerebellar neoplasms were found to be separate primary neoplasms. Furthermore, the pineal gland was normal and the cerebellar neoplasm arose within the vermis as a medulloblastoma. Finally, the two neoplasms had different and characteristically identifiable cytolological and immunohistochemical profiles. The findings of the present study, taken together with those of recent molecular and transgenic studies, support the emerging concept that rb inactivation is not restricted to central nervous system regions of photoreceptor lineage and that inactivation of this tumor suppressor pathway may be relevant to the determination of etiological factors leading to medulloblastoma in humans.

Surgical management of GH-secreting pituitary adenomas: an outcome study using modern remission criteria

The results of transsphenoidal surgery as initial therapy for GH-secreting pituitary adenomas in 57 acromegalic patients were analyzed retrospectively. Patients with prior surgery or radiation therapy were excluded from the study. Three different criteria were used to define remission: glucose-suppressed (nadir) GH less than 1.0 microg/liter, a normal sex- and age-adjusted IGF-I level, and postoperative random GH levels of 2.5 microg/liter or less. Additionally, we analyzed the neuropathological data, including immunohistochemistry and ultrastructural categorization, and the surgical complications. The short-term remission rate (6-wk postoperative follow-up visit), as determined by a random GH measurement of 2.5 microg/liter or less, was 48.8%; the remission rate, as determined by nadir GH, was 51.4%. For 57 patients followed for 12 months or more after surgery (mean, 37.7 months), surgical remission was achieved in 70.2%, 66.7%, and 61.1%, respectively, for patients assessed by normal IGF-I, random GH, and nadir GH. One patient (1.1%) developed recurrence of active acromegaly 81 months after initially successful surgical therapy. Extrasellar growth of the tumor (P = 0.04) and dural invasion by the adenoma (P = 0.008) were significant univariate predictors of a poor outcome. Tumor size was significantly greater in patients with persistent or recurrent acromegaly (P = 0.02). Patients with tumors of the ultrastructural categories of mixed GH/PRL cell and mammosomatotroph adenomas had the lowest remission rates (50% and 42.9%, respectively). There were no perioperative deaths, and there was no serious morbidity. The permanent complication rate was 3.3% (1 permanent DI and 2 nasal septal perforations). Surgical management of acromegaly currently provides prompt, effective, and satisfactory initial treatment for the majority of patients. Using stringent criteria for remission, primary transsphenoidal surgery for GH-secreting pituitary adenomas is effective and often definitive therapy for acromegaly. These results provide a benchmark for the contemporary results of surgical management as assessed by modern outcome criteria.

Radiosurgery-induced microvascular alterations precede necrosis of the brain neuropil

OBJECTIVE

Radiosurgery is used as a therapeutic modality for a wide range of cerebral disorders. It is important to understand the underlying causes of deleterious side effects that may accompany gamma-irradiation of brain tissue. In this study, structural alterations in rat cerebral vessels subjected to gamma knife irradiation in vivo were examined, for elucidation of their potential role in necrosis formation.

METHODS

A maximal center dose of 75 Gy was delivered to the rat parietal cortex with a 4-mm collimator, and changes occurring before necrosis formation were assessed 3.5 months after irradiation. Transmission electron microscopy, using horseradish peroxidase as a tracer, and scanning electron microscopy with vascular casting were performed.

RESULTS

The capillary network in the irradiated area exhibited thickening and vacuolation of the basement membrane. The capillary density in the irradiated area was lower and the average capillary diameter was larger, compared with the nonirradiated side. These results indicate that substantial changes in the neuropil do not occur 2 weeks before the time of definite necrosis formation, whereas changes in the basement membrane are prominent.

CONCLUSION

The necrotic response to intermediate doses of focused-beam irradiation appears after a considerable latency period and then progresses rapidly. This contrasts with previously reported responses to fractionated whole-brain irradiation, in which damage occurs slowly and gradually. Alterations in the microvascular basement membrane precede overt cellular changes in neuronal and vascular cells and provide an early index of cerebrovascular dysfunction in regions destined to undergo necrosis.

An introductory overview of orbital tumors

The term "orbital tumors" comprises a wide variety of lesions that often share the same cardinal clinical finding (exophthalmos) and clinical history. Age at presentation, associated ophthalmological findings, and radiological features, however, provide invaluable information as to the possible histological type of tumor. The present article serves as an introductory overview regarding the pathological characteristics, clinical features, radiological characteristics, and principles of treatment of orbital tumors.

Skull base chordomas: overview of disease, management options, and outcome

Cranial base chordomas are locally invasive tumors that, from a midline, clival location, extend in different directions and display various patterns of skull base invasion. Although histologically benign, their invasive nature makes true “oncological” resection virtually impossible to achieve in most cases, despite modern skull base surgical techniques. Moreover, because of the tumor's location and proximity to critical neural and vascular structures, surgery-related morbidity can be significant when an aggressive resection is undertaken. Cytoreductive surgery assumes a critical role in the management of these lesions. The choice of surgical approach and the extent of resection are dependent on several factors: location and extension of the tumor, the surgeon's philosophy and familiarity with a specific approach, and the patient's preexisting clinical status. Proton-beam radiotherapy seems to be effective as an adjunct to surgery in achieving local tumor control. The timing of radiation therapy, however, remains controversial. Gamma knife surgery has been proposed as an adjunctive therapy, but the limited experience and short follow-up periods do not permit formulation of meaningful conclusions at this time. Recurrences are common, although in a subset of patients prolonged disease-free survival is demonstrated.

Absence of mutations in the growth hormone (GH)-releasing hormone receptor gene in GH-secreting pituitary adenomas

OBJECTIVE

GH-releasing hormone (GHRH) is a potent stimulator of somatotroph cell proliferation and GH secretion. GHRH acts via binding to a G-protein coupled receptor (GPCR) (GHRH-R), that activates adenylyl cyclase (AC) and increases growth and function of somatotroph cells. Indeed, a subset (30--40%) of somatotrophic adenomas contain somatic mutations of the GNAS1 gene that encodes the alpha subunit of the G-protein (G(s)alpha) that stimulates AC. As activating mutations of other GPCRs cause development of endocrine tumours, we hypothesized that somatic activating mutations of the GHRH-R might provide the molecular basis for somatotroph cell proliferation in a subset of human GH-secreting pituitary adenomas.

DESIGN

We analysed genomic DNA isolated from 26 somatotrophinomas, 17 of which lacked activating mutations in the GNAS1 gene. We individually amplified via polymerase chain reaction all 13 coding exons and the exon-intron boundaries of the GHRH-R gene. We used denaturing gradient gel electrophoresis to search for abnormalities in exons 1 through 11. Abnormally migrating bands were subjected to direct sequencing. Exons 12 and 13, encoding for the intracellular C-terminal domain, were subjected to direct sequencing.

RESULTS

Mutations were not detected in any of the tumours, but a rare polymorphism in codon 225 corresponding to the third transmembrane domain (V225I) was discovered.

CONCLUSIONS

GHRH-R mutations are absent or rare in somatotrophinomas, and other mechanisms must explain the somatotroph cell proliferation in the adenomas that lack activating mutations in the GNAS1 gene.

Calvarial hemangiomas: report of two cases and review of the literature

BACKGROUND

Primary hemangiomas of the bone are uncommon tumors, accounting for less than 1.0% of all bone neoplasms. These tumors are mostly found in vertebral bodies. Hemangiomas are rarely seen in the calvarium, where their frequency is 0.2% of all bone neoplasms. Because of their infrequent appearance in the skull, vague symptoms, and absence of prototypical radiological findings, these tumors can be missed in many cases or may be misinterpreted as more ominous lesions like multiple myeloma or osteosarcoma.

CASE DESCRIPTION

We report two cases of calvarial hemangiomas: one with a single mass on the right sphenoid wing, and another with two similar lesions on the right occipital and left parietal bones. The diagnoses could be established only by histopathologic analysis.

CONCLUSION

Histopathologic confirmation of the tumor is the definitive method for diagnosis of intraosseous hemangiomas. Radiological findings are not always characteristic for calvarial hemangiomas. Due to possible complications and the possibility of effective treatment, this lesion should always be considered in the differential diagnosis of skull lesions.

Double pituitary lesions in three patients with Cushing's disease

Double pituitary adenomas are rare in surgical specimens and the most common clinical feature in reported patients has been acromegaly. We report 3 cases of double pituitary lesions in patients who presented with Cushing's disease. In a 22-year-old man (case 1) with delayed puberty and low testosterone levels, mild hyperprolactinemia was diagnosed and treated with dopamine agonist therapy that reduced the prolactin (PRL) levels to normal. Over a 1-year period Cushing's disease developed gradually and was confirmed with classical endocrine testing. In a 27-year-old woman (case 2) who initially presented with severe depression and morbid obesity there was a gradual onset of Cushing's disease; initially she had minimally elevated serum PRL. In a 33-year-old woman (case 3) there was a 2-year history of Cushing's disease characterized by hirsutism, hypertension and weight gain; serum PRL was normal. Magnetic resonance imaging in all 3 patients revealed a microadenoma that was successfully removed by transsphenoidal pituitary surgery. Histology and immunocytochemistry in case 1 and case 3 revealed a corticotroph cell adenoma and a PRL cell adenoma in separate areas of the pituitary. In case 3 the PRL cell adenoma was "silent" but in case 1 the PRL cell adenoma may have been the cause of the mild hyperprolactinemia. In case 2 nodular corticotroph hyperplasia was the cause of Cushing's disease and a "silent" PRL cell adenoma was also identified. We conclude from these cases and a literature review that double pituitary lesions may occur in patients with Cushing's disease. The corticotroph part of the double lesion may consist of a corticotroph cell adenoma or, as reported in this study, of corticotroph nodular hyperplasia. The counterpart of the double lesion may consist either of a "silent" PRL cell adenoma or a functional PRL cell adenoma causing hyperprolactinemia.

Electromyographical study of the iliocostalis lumborum, longissimus thoracis and spinalis thoracis muscles in various positions and movements

The iliocostalis lumborum, longissimus thoracis and spinalis thoracis muscles were studied electromyographically in six male individuals between 18 and 23 years old. They were connected to co-axial needle electrodes while in orthostatic, kneeling and sitting positions performing movements of flexing, extending and rotating the trunk. In the total flexing of the trunk the muscles did not present any action potential. The results showed intense potential for action while flexing the trunk 45 degrees, extending the trunk beginning at 45 degrees of flexing and in homolateral rotation for the muscles analyzed in the orthostatic position, emphasizing the iliocostalis lumborum muscle in the extension of the trunk which registered very strong action potentials in all individuals. There were similar results for movements of flexing and extending the trunk in the kneeling position, emphasizing the longissimus thoracis muscle in the movement of hyperextension. In the sitting position the more intense potentials were for the movements of extension, flexing with rotation and homolateral rotation of the trunk, emphasizing the longissimus thoracis muscle with strong potentials.

Results of transsphenoidal surgery for Cushing's disease in patients with no histologically confirmed tumor

OBJECTIVE

Pathological confirmation of surgical resection of an adenoma for Cushing's disease is not always achieved. We reviewed our experience to determine the prognostic significance of this lack of confirmation regarding outcome, and we evaluate explanations for this situation.

METHODS

The records of all patients undergoing transsphenoidal surgery for Cushing's disease from 1992 to 1998 were reviewed, and those with no histological confirmation of tumor were identified. Information regarding preoperative and postoperative hormonal levels and clinical symptoms, preoperative magnetic resonance imaging data, intraoperative findings, and the number of reoperations were recorded.

RESULTS

There were 29 patients with no confirmation of tumor. Nineteen (66%) of these patients were cured with surgery and only one had a recurrence of disease, with an average follow-up of 38 months. An abnormality thought to represent an adenoma at the time of surgery was removed in 26 patients (90%). Preoperative magnetic resonance imaging suggested a discrete lesion in 21 patients (72%). Neither intraoperative impression nor magnetic resonance imaging appearance was correlated with outcome.

CONCLUSION

Patients with no histological confirmation of tumor after transsphenoidal surgery for Cushing's disease are likely to have a good outcome. The results do not differ significantly from reported cure rates in patients with confirmed adenomas. Possible explanations for this situation are discussed.

Bovine type I collagen as an endovascular stent-graft material: biocompatibility study in rabbits

PURPOSE

To study the biocompatibility of a bovine type I collagen preparation as a material for small-vessel stent-grafts in rabbits.

MATERIALS AND METHODS

A composite nitinol-collagen endovascular stent-graft with a 4-mm inner diameter was deployed in the abdominal aorta in nine rabbits. Angiography was performed, and the rabbits were sacrificed at 1, 2, and 7 days and at 1 and 3 months. The portion of the aorta containing the stent-graft was excised and was histologically evaluated.

RESULTS

All stent-grafts were patent at all time points. On days 1, 2, and 7 after implantation, scattered red and white blood cells adhered to the stent-graft. At 1 month, the stent-graft was endothelialized and was infiltrated with fibroblasts that deposited collagen within the interstices of the implanted collagen material. At 3 months, there was additional collagen deposition within the interstices of the stent-graft that did not narrow the lumen of the stent-grafts.

CONCLUSION

Type I collagen as a intravascular stent-graft material is biocompatible for at least 3 months in rabbits. It is rapidly endothelialized and does not cause reactive stenosis. As a versatile and biocompatible polymer, collagen is potentially useful in the construction of endovascular stent-grafts for use in human arteries.

[Bodies scorned: when medicine and caricature meet]

With the advent of the illustrated press, in 1840, the art of caricature initiated an interesting dialogue with historical painting and portraiture. The article shows dr. Oswaldo Cruz as target of this humorous language in the early twentieth century. Caricature -- a line that cries out -- recognizes the pain of its injured subject and, under an unwritten intersubjective pact, uses humor to release the violence of suffered aggression.

Insulin-like growth factor-1 content and pattern of expression correlates with histopathologic grade in diffusely infiltrating astrocytomas

Studies of experimental tumorigenesis have strongly implicated signaling of the insulin-like growth factor 1 (IGF-1) as a key component in astrocytic neoplasia; however, its role in the growth of low-grade and malignant human tumors is not well understood. Correlative analyses of IGF-1, p53, and Ki-67 (MIB-1) immunohistochemistry and IGF-1 receptor (IGF-1R) mRNA expression were performed to examine the cellular pattern of IGF-1 signaling in 39 cases of astrocytoma (World Health Organization grades II-IV). Tumor cells expressing IGF-1 and IGF-1R were present in all tumor grades. The proportion of tumor cells that expressed IGF-1 correlated with both histopathologic grade and Ki-67 labeling indices, while expression of IGF-1R mRNA correlated with Ki-67 indices. In cases where stereotactic tissue sampling could be identified with a specific tumor area by neuroimaging features, the numbers of IGF-1 immunoreactive cells correlated with the tumor zones of highest cellularity and Ki-67 labeling. In glioblastomas, the localization of IGF-1 immunoreactivity was notable for several features: frequent accentuation in the perivascular tumor cells surrounding microvascular hyperplasia; increased levels in reactive astrocytes at the margins of tumor infiltration; and selective expression in microvascular cells exhibiting endothelial/pericytic hyperplasia. IGF-1R expression was particularly prominent in tumor cells adjacent to both microvascular hyperplasia and palisading necrosis. These data suggest that IGF-1 signaling occurs early in astroglial tumorigenesis in the setting of cell proliferation. The distinctive correlative patterns of IGF-1 and IGF-1R expression in glioblastomas also suggest that IGF-1 signaling has an association with the development of malignant phenotypes related to aberrant angiogenesis and invasive tumor interactions with reactive brain.

Control of primary angiitis of the CNS associated with cerebral amyloid angiopathy by cyclophosphamide alone

Corticosteroids combined with cyclophosphamide are currently recommended for primary angiitis of the CNS. The authors report a 71-year-old man with primary angiitis of the CNS and amyloid angiopathy who responded to cyclophosphamide without steroids, suggesting that corticosteroids may not be needed in all cases of primary angiitis of the CNS.

Estrogen receptors in prolactinomas: a clinico-pathological study

BACKGROUND

Antiestrogens are effective in the treatment of estrogen receptor (ER) positive breast carcinoma. The use of antiestrogen therapy in pituitary adenomas, however, has not been explored. This study attempted to identify a population who may benefit from antiestrogen therapy.

MATERIALS & METHODS

Prolactinomas from 29 patients (10 men, 19 women) were analyzed for ER and Ki-67 labeling index using immunohistochemistry. Nine of the 19 women were either amenorrheic or had not received exogenous estrogen for at least one year. Ten women were menstruating either spontaneously or as a result of estrogen administration. Factors including age, serum prolactin level, tumor size, evidence of tumor invasiveness and recurrence of tumor were evaluated to determine if they were predictive of ER expression.

RESULTS

Tumors from 6/10 (60%) men were positive for ER. Among women who were having menses, 9/10 (90%) tumors were positive, whereas 6/9 (67%) tumors from amenorrheic women were positive. Statistical analysis revealed that none of the variables: gender, age, menstrual status, Ki-67 proliferative rate, exposure to dopamine agonists, preoperative prolactin level, tumor size, or invasiveness was predictive for the presence of the receptor. The incidence of ER, however, was significantly reduced in recurrent tumors (p = 0.03).

CONCLUSIONS

ER expression is less likely in recurrent tumors. The efficacy of ER antagonists cannot be inferred by gender or estrogen exposure.

Selective expression of estrogen receptor alpha and beta isoforms in human pituitary tumors

The physiological effects of estrogen on the pituitary, including cellular proliferation and regulation of hormone synthesis, are mediated by the nuclear estrogen receptor (ER). The ER acts as a dimer to modulate gene transcription and contains specific functional domains encoded in different exons. Two separate, but related, forms of the receptor (ERalpha and ERbeta) exist, with distinct tissue and cell patterns of expression. Additional ER isoforms, generated by alternative messenger ribonucleic acid (mRNA) exon splicing, have been defined in several tissues and are postulated to play a role in tumorigenesis or in modulating the estrogen response. We examined 71 human pituitary adenomas of varying phenotypes and 6 normal pituitary specimens for ER mRNA forms by RT-PCR and hybridization blotting analysis. All prolactinomas (n = 14) contained ERalpha, and several contained ERbeta (5 of 14) mRNA. In comparison, 6 tumors that expressed PRL and GH expressed ERbeta (4 of 6) more frequently than ERalpha (3 of 6). ERbeta mRNA was also found more frequently in null cell (8 of 24 ERalpha and 14 of 24 ERbeta) and gonadotrope (13 of 21 ERalpha and 18 of 21 ERbeta) tumors. Additionally, ERbeta was found in 4 of 6 tumors that contained only GH, although ERalpha was not observed in this tumor type. Expression of the two ER forms within a tumor type was overlapping, but some tumors contained only 1 isoform. Expression of ERalpha mRNA splice variants also varied with cell type. All normal pituitaries contained ERalpha deletions of exon 4, 5, and 7, whereas only 2 of 6 samples contained the exon 2 deletion variant. Although the same ERalpha mRNA variants were observed among the various tumor types, the proportion of specific splice variants expressed varied. For example, most ER-positive prolactinomas expressed ERalpha variants with deletions of exon 2, 4, or 5, whereas gonadotropin tumors preferentially expressed the ERalpha exon 7 deletion variant. A novel ERbeta mRNA splice variant, missing exon 2, was observed in a majority of all ERbeta-positive tumors. Immunoblotting analysis of ERalpha and ERbeta proteins supported the mRNA results. Because ERalpha and ERbeta have different biological responses to selective ER modulators, and the ER deletion variants have biological effects distinct from those of the full-length ER, expression of these isoforms may influence the biological properties of these tumors and affect their ability to respond to estrogen and antiestrogen therapies.

Determination of growth fraction and cell density to evaluate the potential growth of human oligodendroglial and astrocytic tumours

The object of this work was

PURPOSE

to develop a methodology that enables net tumour growth, a balance between actual tumour growth and tumour cell loss, to be approximately evaluated.

METHODS

The methodology proposed relies on detecting the growth fraction immunohistochemically by means of MIB-1 antibody labelling combined with cell density determination, carried out on 5-microm-thick Feulgen-stained histological sections with computer-assisted microscopy. The series investigated included 25 oligodendrogliomas (OLG-II), 9 anaplastic oligodendrogliomas (OLG-III). 13 astrocytomas (AST), 14 anaplastic astrocytomas (ANA) and 8 mixed oligoastrocytomas (OLG-AST).

RESULTS

The results show that the biological characteristics of some cases were in total accordance with their histopathological diagnoses. This was the case for the "weakly proliferating weakly dense" OLG-II and AST-II tumours, and for the "highly proliferating highly dense" OLG-III and AST-III ones. In contrast, the biological characteristics of some cases seemed to contradict the histopathological case labels. This was the case for the "highly proliferating highly dense" OLG-II and AST-II tumours, the biological aggressiveness of which would be undervalued on the basis of the morphology-based grading system alone, and also for the "weakly proliferating weakly dense" OLG-III and AST-III tumours, the aggressiveness of which would be overvalued.

CONCLUSIONS

Combining the determinations of the MIB-1 and the cell density variables appears to be satisfactory in terms of the cell kinetic characterization of glial tumours as a complement to the prognostic information given by a morphology-based grading system alone.

Primary fibrosarcoma of the sella unrelated to previous radiation therapy

Fibrosarcomas involving the sella turcica are rare lesions and, when encountered, have been associated with previous radiation of a pituitary adenoma. Although primary intracranial fibrosarcomas are well recognized, no case of primary fibrosarcoma of the sella turcica has been reported to date. We describe here a patient who presented with a 2-month history of headache, visual disturbances, and diabetes insipidus. Her past medical history was unremarkable, with no radiation therapy. Magnetic resonance imaging revealed a sellar/suprasellar lesion that at surgery appeared firm in consistency. A radical removal of the mass was performed through a transsphenoidal approach. The patient recovered promptly from the operation and 2 weeks later, given the aggressive histologic appearance of the lesion, underwent gamma knife radiosurgery. Seven months after diagnosis, the patient presented with local tumor recurrence. A subtotal surgical resection was performed, and additional postsurgical treatment is still under consideration. Although most often related to previous radiation of the pituitary gland, primary fibrosarcomas can occur in the sella. This possibility should be suspected in the differential diagnosis of sellar masses that lack the classical characteristics of the much more common pituitary adenomas.

Platinum coil-mediated implantation of growth factor-secreting endovascular tissue grafts: an in vivo study

PURPOSE

To demonstrate in vivo that platinum embolic coils can be used to deliver genetically modified, growth factor-secreting fibroblast grafts into the endovascular space with the long-term goal of improving fibrosis within coil-embolized cerebral aneurysms.

MATERIALS AND METHODS

Murine fibroblasts that contained multiple inserts of the DNA for human basic fibroblast growth factor were grown in culture onto 10-mm-long segments of Guglielmi detachable coils. Control (n = 4) and fibroblast-bearing (n = 4) coils were implanted into the common carotid artery in nude rats. The arterial segments that contained the coil were harvested after 14 or 35 days. Cellular content and collagen formation in the treated vessels were assessed histologically.

RESULTS

At both 14 and 35 days, samples with control coils showed primarily involuting blood elements with minimal fibroblast proliferation or collagen formation. At 14 days, samples with fibroblast-bearing coils showed extensive fibroblast proliferation. At 35 days, samples with fibroblast-bearing coils showed marked interval fibroblast proliferation and collagen formation.

CONCLUSION

Platinum coils can be used as a cell delivery device. Direct intravascular implantation of growth factor-secreting fibroblast grafts leads to improved intravascular scar formation, therefore theoretically reducing the potential for aneurysm regrowth or coil compaction.

Sulfonylurea receptor mRNA expression in pituitary macroadenomas

ATP-sensitive K+ (KATP) channels modulated by sulfonylurea compounds have been previously identified in the anterior pituitary of the rat and have been demonstrated to influence GH release. Recently, a sulfonylurea receptor (SUR) has been cloned from an islet cell tumor and identified as a member of the ATP binding cassette superfamily capable to coupling with inwardly rectifying potassium channels. To determine if the same receptor is expressed in pituitary tumors, SUR mRNA levels were measured in 28 human macroadenoma specimens using an RNase protection assay. All immunonegative, corticotrophin (ACTH), growth hormone (GH), and GH/prolactin (GH/Prl) immunostaining tumors expressed detectable amounts of SUR message. Among these tumors, only the GH and GH/ Prl adenomas were functional. Of the tumors immunostaining for luteinizing hormone (LH), follicle-stimulating hormone (FSH), or both, SUR mRNA was present in small amounts in 5/11. Only 1/3 Prl immunostaining tumors contained SUR mRNA. In summary, we have demonstrated that SUR mRNA expression is common in several types of silent pituitary adenomas and in functional tumors that secrete GH. Lower levels are seen in some gonadotrophin immunostaining tumors.

Mature pulmonary lobar transplants grow in an immature environment

OBJECTIVE

Mature lobar transplantation will increase the pediatric donor organ pool, but it remains unknown whether such grafts will grow in a developing recipient and provide adequate long-term support. We hypothesized that a mature pulmonary lobar allograft implanted in an immature recipient would grow.

METHODS

We investigated our hypothesis in a porcine orthotopic left lung transplant model using animals matched by the major histocompatibility complex to minimize the effects of chronic rejection. Twenty-three immature animals (< 12 weeks of age and < 10 kg total body weight) received either sham left thoracotomy (SH control, n = 4), left upper lobectomy to study compensatory growth (UL control, n = 4), age-matched immature whole left lung transplants (IWL TXP, n = 6), mature (donor > 1 yr in age and > 40 kg in total body weight) left lower lobe transplants (MLL TXP, n = 5), or mature left upper lobe transplants (MUL TXP, n = 4). Twelve weeks after implantation, functional residual capacity of the left lung was measured and arterial blood gas samples were obtained after the native right lung had been excluded. The graft was excised and weighed, and samples for microscopy and wet/dry ratios were collected.

RESULTS

Initial and final graft weights were as follows: IWL TXP group (34.6 +/- 1.5 and 107.8 +/- 5.9 gm, p < 0.0001), MLL TXP group (72.4 +/- 6.8 and 111.4 +/- 8.7, p < 0.001), and MUL TXP group (32.8 +/- 1.3 and 92.8 +/- 7.1 gm, respectively, p < 0.004). No significant differences between groups were demonstrated when functional residual capacity, wet/dry ratios, or oxygenation were compared. Immunohistochemical staining for the nuclear antigen Ki-67 demonstrated dividing pneumocytes.

CONCLUSIONS

We conclude that a mature lobar graft implanted into an immature recipient grows by pneumocyte division in this model. Mature lobar transplants can be expected to grow and provide adequate long-term function in developing recipients.

Growth hormone-releasing hormone receptor mRNA in acromegalic pituitary tumors

The growth hormone (GH)-releasing hormone receptor (GHRH-R) has been recently cloned and found to be a member of a new family of seven transmembrane receptors that includes secretin, vasoactive intestinal peptide, calcitonin, and corticotropin-releasing factor. GHRH-R mRNA has been demonstrated by Northern blot analyses to be present specifically in the anterior pituitary gland. To determine the precise cellular localization of this receptor in normal anterior pituitary and pituitary adenomas, GHRH-R mRNA was analyzed in 2 normal human pituitary glands and 16 human pituitary adenomas using in situ hybridization. GHRH-R was specifically localized in somatotroph cells in the normal pituitary. In the adenomas, all GH-producing adenomas originating from acromegalic patients demonstrated up-regulation of GHRH-R mRNA when compared with levels in the normal pituitary. Only one of five clinically nonfunctioning adenomas, a gonadotroph luteinizing hormone/follicle-stimulating hormone-positive adenoma, exhibited up-regulation of this receptor message. Adrenocorticotrophic hormone-secreting and prolactin-secreting adenomas did not express GHRH-R message. In summary, GHRH-R is specifically expressed in somatotrophs and GH-producing adenomas, suggesting that GHRH-R may influence GH release in adenomas similar to this receptor's actions in the normal somatotrophs and may be involved in the growth of GH-secreting adenomas.

Ganglioglioma: an ultrastructural and immunohistochemical study

BACKGROUND

Ganglioglioma is a rare, mixed neuronal-glial neoplasm of the central nervous system that occurs in young patients and has a benign clinical course.

METHODS

To define the immunophenotypic and morphologic features of ganglioglioma precisely, 27 specimens were studied by routine histochemistry, 21 specimens by immunochemistry, and 14 specimens were examined at the ultrastructural level.

RESULTS

The age of the 27 patients, 14 males and 13 females, ranged from 3 to 52 years (mean, 22 years). The most commonly affected site was the temporal lobe (13 patients). Three patients experienced a local recurrence. Microscopically, the tumors were comprised of well differentiated, somewhat abnormal neurons as well as glial cells, the latter including astrocytes of fibrillary (59%) and pilocytic (41%) type. Scant mitotic activity was observed in 2 tumors (7%). Glial cells of all tumors were immunoreactive for glial fibrillary acidic protein, S-100 protein, and vimentin. Ki-67 labeling indices (LI) ranged from 0.6 to 10.5% (mean, 2.7%) and p53 LI from 1.1 to 42.4% (mean, 15.6%). Ki-67 and p53 LI in recurrent tumors were significantly higher than those of nonrecurrent ones (P = 0.036 and 0.026, respectively). No examples of anaplastic transformation were encountered. Immunohistochemically, many neuronal cells were positive for synaptophysin (100%), Class 3 beta-tubulin (100%), neurofilament protein (90%), and chromogranin A (86%), in addition to S-100 protein (71%) and, occasionally, vimentin (24%). Ultrastructural characteristics of neuronal cells included the presence of numerous, 100-230-nanometer dense core granules within both perikarya and cell processes, well developed rough endoplasmic reticulum, microtubules within cell processes, and synapses associated with clear vesicles. Astrocytic cells usually contained abundant intermediate filaments; their cell membranes, when abutting the stroma, were covered by basal lamina.

CONCLUSIONS

Gangliogliomas are comprised of well differentiated neuronal cells and glial cells that are very often of pilocytic type. No cells with features intermediate between neurons and glia were observed. Neuronal cells are characterized by prominent neurosecretory features distinct from those of normal neurons in the central nervous system. Higher Ki-67 and p53 LI may indicate more aggressive behavior.

Maturation of intracranial immature teratomas. Report of two cases

Immature teratomas arising within the central neuraxis are rare neoplasms. These tumors contain diverse cell lineages that retain an embryonal character and display phenotypic differentiation attributed to the three classic germ layers. The clinical management of these lesions is unclear, due in part to their low incidence and to an incomplete understanding of their natural history. Although the potential for phenotypic differentiation and cellular maturation within immature teratomas arising in the gonads is well documented, this has not been described in the intracranial tumors. In the present report, the authors describe two cases of intracranial immature teratomas, one involving the pineal region and the other involving the left frontotemporal lobes, which underwent cellular differentiation and maturation. At initial resection, the tumors from both cases were composed predominantly of primitive neuroepithelial tissue that was admixed with immature and differentiating mesenchymal and epithelial structures. No foci of germinoma, endodermal sinus, choriocarcinoma, or embryonal carcinoma tissue were present. Subsequent resections in both cases revealed an absence of immature tissue. The tumor in Case 1 contained only differentiated epithelial and mesenchymal tissue with no neuroepithelial component, whereas the tumor in Case 2 demonstrated abundant mature neuronal and glial tissue. These two cases from different intracranial sites suggest that spontaneous maturation may be a significant aspect of the natural history of intracranial immature teratomas.

Occlusion of the anterior cerebral artery after Gamma Knife irradiation in a rat

The anterior cerebral artery of rats was irradiated at the level of the circle of Willis by Gamma Knife with a maximum dose of 25, 50, or 100 Gy. Occlusion of the anterior cerebral artery was observed in one rat which was followed for 20 months after irradiation of 100 Gy. Cerebral infarction was found at the midline-frontal region and the cingulate gyrus. Arterial wall thickening with fibrosis, splitting of the internal elastic membrane, luminal organized thrombus, and migration of smooth muscle cells into the thrombus were observed. In the anterior cerebral artery, thrombus formation seemed to occur after the endothelial injury and this may play a prominent role for occlusion. In small arteries, various changes were observed in the irradiated tissue. These included fibrosis and thrombus, thickened smooth muscle layer, lymphocytic infiltration, and thickening of vessel wall with fibrosis and fibrinous thrombosis with leakage of fibrin into the surrounding tissue after different doses of radiation and at different observation times. These changes were comparable to the ordinary vascular response to injury including healing vasculitis and arteriosclerosis.

Histological changes in the normal rat brain after gamma irradiation

Radiation-induced changes in the parietal cortex of Wistar rats were observed at various time points after gamma surgery. Maximum dosages of 50, 75, and 120 Gy were given at the iso-center of the radiation using a 4-mm collimator. Conventional histochemical and immunocytochemical analyses, and computer-assisted videomicroscopy were utilized to examine perfusion-fixed brain tissue. Irradiation at a dosage of 50 Gy elicited morphological changes of astrocytes in the parietal cortex at 3 months. Vasodilatation became obvious at 12 months; fibrin deposition was observed in the dilated capillary wall. Neither leakage of Evans Blue from the vasculature into the tissue nor necrosis was observed across the 12 month observation period. Irradiation at a dosage of 75 Gy resulted in morphological changes of astrocytes within 1 month. Dilatation of vessels and capillary thickening were observed at 3 months. Evans Blue leakage and necrosis were observed at 4 months after 75 Gy irradiation. At this time, the walls of arterioles became thickened by subintimal accumulation of fibrin and hyaline substance; this sometimes resulted in occlusion of the lumen. Significant hemispheric swelling was observed at 4 months. Irradiation at a dosage of 120 Gy elicited changes in astrocytic morphology within 3 days. Evans Blue leakage into the tissue was observed by 3 weeks. Vasodilation became marked at this time point and rarefaction was observed in the irradiated cortex. Necrosis was observed at 4 weeks, however, no significant swelling was observed. Taken together, these findings demonstrate time-dependent and dosage-dependent changes in normal cerebral tissue after Gamma Knife irradiation. These results provide a basis for gauging the impact of gamma surgery in regions of eloquent tissue. An enhanced understanding of the cellular responses to radiosurgery will contribute to developing and evaluating future applications for gamma surgery.

Immunohistochemical characterization of subependymal giant cell astrocytomas

Subependymal giant cell astrocytoma (SEGA) is the most common neoplastic process involving the brain in patients with tuberous sclerosis complex (TSC). Morphologically, these tumors exhibit a wide range of cytoarchitecture with spindle and epithelioid cells resembling astrocytes, and also large, occasionally giant cells, some of which have a distinctly ganglion-like appearance. Unresolved questions regarding SEGAs center on: (a) their cytogenesis, i.e., whether they are derived from single or multiple precursors; and (b) their differentiating capacity along glial or neuronal lines. We sought to determine whether SEGAs represent truly mixed tumors or whether they consist of a single population of cells with a capacity for divergent differentiation. Twenty SEGAs were assessed for immunophenotypic features of either neuronal or glial differentiation or both. Only tumors from patients with a clinically confirmed diagnosis of TSC were included. Immunoreactivity for glial fibrillary acidic protein (GFAP) and/or S-100 protein was considered indicative of a glial phenotype, whereas the presence of neuronal differentiation was assessed by staining for cytoskeletal proteins [neurofilament epitopes, class III Beta-tubulin, microtubule-associated protein 2 (MAP2), synaptophysin], neurosecretory substances [serotonin, cholecystokinin, Beta-endorphin, substance P, somatostatin, metenkephalin, neuropeptide Y, vasoactive intestinal polypeptide (VIP), and for the 28-kDa neuron-associated calcium binding protein calbindin. Of the tumors examined, 18 exhibited both glial and neuronal epitopes, the staining pattern being variable. In 19 tumors, the constituent spindle, polygonal and giant or ganglion-like cells showed variable immunoreactivity for GFAP and S-100 proteins both within the cell body and processes. Neuron-associated cytoskeletal proteins were present in 18 cases. Class III Beta-tubulin immunoreactivity was demonstrated in 17 tumors, both within the bodies of all three cell types and to varying degrees within their processes. Neurofilament protein and calbindin staining was present in 8 tumors, with reactivity for the former being distributed in a phosphorylation-dependent manner. MAP2 was detected in a few cells of two tumors. Immunoreactivity for neuropeptides was observed in 17 lesions. Somatostatin and metenkephalin staining was noted in 10 tumors (50%) being present particularly within polygonal cells. Neuropeptide Y, serotonin and Beta-endorphin reactivity was found in 6 (30%), 5 (25%), and 4 tumors (20%), respectively; Beta-endorphin was lacking in giant cells, whereas neuropeptide Y and serotonin were seen within their cell bodies. Substance P and VIP were evident in only occasional polygonal cells of 2 (10%) and 1 tumor (5%), respectively. Stains for cholecystokinin were negative. The observation of immunoreactivity for both glial- and neuron-associated epitopes within tumor cells of the same morphology suggests that SEGAs represent proliferations of cell lineages with the capacity to undergo divergent glioneuronal as well as neuroendocrine differentiation to a greater extent than do other mixed glial-neuronal neoplasms.

Alzheimer's disease in a case of cortical basal ganglionic degeneration with severe dementia

Images

1995 AUR Memorial Award. Gamma knife irradiation-induced changes in the normal rat brain studied with 1H magnetic resonance spectroscopy and imaging

RATIONALE AND OBJECTIVES

The pathogenesis of brain injury following radiosurgery is poorly understood. To better elucidate the relationship between blood-brain barrier disruption and metabolic derangements, we used magnetic resonance (MR) imaging and 1H MR spectroscopy to detect early changes from focused single-fraction, high-dose irradiation injury in rat brains.

METHODS

Using the Leksell gamma knife, we irradiated the frontoparietal cortex of 11 male Wistar rats with a single dose of 120 Gy. Four weeks later, we sequentially performed water-suppressed 1H MR spectroscopy and gadopentetate dimeglumine-enhanced T1-weighted MR imaging. Metabolic maps were created of n-acetylaspartate (NAA), creatine and choline (Cr/Cho), and lactate from the MR spectroscopy data set. Detection of irradiation injury among the tested modalities was assessed by receiver operating characteristic analysis and by quantitative signal intensity changes. Pathologic confirmation of irradiation damage was obtained in all rats.

RESULTS

Gadopentetate dimeglumine-enhanced T1-weighted MR imaging was the only imaging modality that detected statistically significant signal intensity changes (p < .05). No reproducible changes in the metabolites of interest could be detected by 1H MR spectroscopy.

CONCLUSION

In our animal model, blood-brain barrier disruption was a reproducible, integral finding of single-fraction, high-dose irradiation injury. No reproducible metabolic derangements of ischemia or necrosis were detected by 1H MR spectroscopy, possibly because of dose-latency effects or sensitivity issues.

Tuber and subependymal giant cell astrocytoma associated with tuberous sclerosis: an immunohistochemical, ultrastructural, and immunoelectron and microscopic study

The cellular nature of the giant eosinophilic cells of tuber and of the cells comprising subependymal giant cell astrocytoma (SEGA) in tuberous sclerosis (TS) remains unclear. To assess the characteristics of these lesions, 13 tubers and 6 SEGA were immunohistochemically studied with glial and neuron-associated antigens. In addition to conventional ultrastructure, 6 tubers and 8 SEGA were subjected to immunoelectron microscopic study for glial fibrillary acidic protein (GFAP) and somatostatin. Eosinophilic giant cells of tubers were positive for vimentin (100%), GFAP (77%) and S-100 protein (92%); such cells were also found to a various extent to be reactive for neuron-associated antigens, including neurofilament (NF) proteins (38%) or class III beta-tubulin (77%). SEGA also showed variable immunoreactivity for GFAP (50%) or for S-100 protein (100%); NF epitopes, class III beta-tubulin, and calbindin 28-kD were expressed in 2 (33%), 5 (83%) and 4 (67%) cases, respectively. Cytoplasmic staining for somatostatin (50%), met-enkephalin (50%), 5-hydroxytryptamine (33%), beta-endorphin (33%) and neuropeptide Y (17%) was noted in SEGA, but not in tubers. Ultrastructurally, the giant cells of tubers and the cells of SEGA contained numerous intermediate filaments, frequent lysosomes and occasional rectangular or rhomboid membrane-bound crystalloids exhibiting lamellar periodicity and structural transition to lysosomes. Some SEGA cells showed features suggestive of neuronal differentiation, including stacks of rough endoplasmic reticulum, occasional microtubules and a few dense-core granules. Furthermore, in one case of tuber, a process of a single large cell was seen to be engaged in synapse formation. Intermediate filaments within a few cells of both lesions were decorated by gold particle-labeled GFAP antiserum. Within the tumor cells of SEGA, irregular, non-membrane-bound, electron-lucent areas often contained somatostatin-immunoreactive particles, whereas the latter could not be detected in tuber. The present study provides further evidence of divergent glioneuronal differentiation, both in the giant cells of tubers and the cells of SEGA. The findings of similar cells at different sites, including the subependymal zone, white matter ("heterotopias"), and cortex indirectly supports the idea that these lesions of TS result from a migration abnormality.

Failure in management of pituitary tumors discussion of 3 cases

Three patients with pituitary adenomas (ACTH-secreting, non-secretory, and multi-secretory) with unfavorable course, in spite of repeated microsurgery, drug therapy, as well as radiotherapy and radiosurgery, are presented. Each case was re-evaluated for possible flaws in management. Two of the invasive tumors continued to grow, in spite of correct management. The third patient with a pituitary adenoma underwent microsurgical resection, and later following a false positive finding of recurrence, received radiotherapy and underwent radiosurgery. The lesion actually was chronic inflammatory tissue.

Olfactory neuroblastoma. An immunohistochemical, ultrastructural, and flow cytometric study

BACKGROUND

Olfactory neuroblastoma is an uncommon neuroectodermal tumor of the upper nasal cavity, microscopic features of which are not always homogeneous. No morphologic features have been found to correlate reliably with prognosis.

METHODS

Twenty-six olfactory neuroblastomas occurring in 14 females and 12 males, ages 18-78 years, were studied by immunohistochemistry, electron microscopy, and DNA flow cytometry. Survival rates were statistically analyzed relative to several variables.

RESULTS

Microscopically, 22 tumors formed a morphologic spectrum intermediate between paraganglioma (PG) and neuroblastoma (NB). Others included two ganglioneuroblastomas (GNB), one lesion exhibited biphasic (neuronal and epithelial) differentiation, and one tumor showed predominantly epithelial features. Immunoreactivity for neuronal and neuroendocrine markers included synaptophysin in 77%, neurofilament protein in 38%, class III beta-tubulin in 81%, and chromogranin A in 77%. In 88% of cases, elongated S-100 protein-positive cells surrounded tumor lobules. Cytokeratin and epithelial membrane antigen immunoreactivity were noted in six (23%) and two (8%) tumors, respectively. Aberrant p53 expression was detected in 16 tumors (62%). The Ki-67 labeling index (LI) varied from 0%-43.8% (mean, 7.4%). Ultrastructurally, 80-230 nm dense core granules were noted within perikarya and as in microtubule-containing processes in all of the 11 tumors studied by electromicroscopy. Lobules of seven tumors were surrounded by electron-dense sustentacular cells. Epithelial tumors exhibited obviously epithelial features in addition to neuronal differentiation. DNA flow cytometry demonstrated a high incidence of polyploidy and aneuploidy (78%) and a wide range of percent S phase fractions (1.5%-21.8%; mean, 9.0%). The study showed that longer survival rates are related significantly to (1) the occurrence of metastases which was linked to tumor subtype, (2) to a higher incidence of S-100 protein-positive cells, and (3) to a low (< 10%) Ki-67 labeling index.

CONCLUSIONS

The present study indicates that (1) although typical olfactory neuroblastomas exhibit PG/NB differentiation, they more closely resemble PG, (2) occasional tumors show GNB and/or epithelial differentiation, and (3) survival rates may correlate with S-100 protein immunoreactivity and Ki-67 LI. Cancer 1995; 76:4-19.

Estrogen receptor expression in human pituitary: correlation with immunohistochemistry in normal tissue, and immunohistochemistry and morphology in macroadenomas

Forty-one human pituitary adenoma specimens were examined for the presence of estrogen receptor (ER) messenger ribonucleic acid and protein using a combination of ribonuclease protection assay, [3H] estradiol ([3H]E2) binding, and ER immunohistochemistry. ER messenger ribonucleic acid prevalence was high in PRL-immunoreactive tumors (2 of 2), moderate in GH/PRL tumors (2 of 5), and low or absent (0 of 4) in GH tumors. In the GH/PRL-immunostaining tumors, the presence of the ER was uniformly associated with elevated serum PRL levels. Among the gonadotropin-immunostaining tumors, 10 of 17 were ER positive; within this group, those with gonadotroph adenoma characteristics were ER positive, whereas those with null cell/oncocytic characteristics were ER negative. Of the tumors that did not immunostain for any known anterior pituitary hormones, 3 of 11 were ER positive. ER immunohistochemistry in 14 tumors revealed a 100% correlation with ribonuclease protection assay results, whereas [3H]E2 binding, determined in 9 tumors, showed an 87% correlation. In summary, it appears that PRL and a specific class of gonadotropin-immunostaining tumors (identifiable by specific characteristics on electron microscope) contain ER, whereas GH-immunostaining tumors are ER negative. ER expression in normal pituitary paralleled that in macroadenomas (GH, 2.3%; PRL, 50%; FSH, 70%; LH, 83%; TSH, 4%; ACTH, 1%). The ER-positive tumors represent a subset whose growth and secretory profiles may be influenced by the gonadal steroidal milieu or by pharmacological agents that affect E2 levels or ER function.

Dysembryoplastic neuroeptihelial tumor (DNT): an immunohistochemical and ultrastructural study

To assess the range of differentiation of the cells comprising dysembryoplastic neuroepithelial tumor (DNT), particularly the oligodendrocyte-like cells (OLC), 14 DNT were immunochemically studied with a spectrum of neuronal and glial markers. Eight tumors were also studied ultrastructurally. Neurofilament protein, class III beta-tubulin, and synaptophysin preparations stained a few OLC in two, six and one lesion, respectively. In addition, many OLC within a single cortical nodule were reactive for class III beta-tubulin. The vast majority of OLC were strongly S-100 protein positive. Glial fibrillary acidic protein labeled a fair number of OLC in two cases and one nodule consisted almost entirely of immunoreactive astrocytes. Ultrastructurally, many OLC resembled oligodendrocytes in exhibiting microtubules, prominent Golgi and short cell processes; pericellular lamination of cell processes, a characteristic of oligodendroglia, was noted in only one tumor. In two cases, OLC with astrocytic features were seen to contain small numbers of intermediate filaments. In four cases, a few OLC resembled immature neurons with scant dense-core granules or synapses. This study confirms the glioneuronal nature of DNT, a lesion composed of heterogeneous cells, many resembling oligodendrocytes and a few showing early astrocytic and neuronal differentiation. Although their relation to OLC is unclear, the presence and peculiar distribution of mature neurons is nonetheless an integral diagnostic feature of the lesion.

Expression of alpha 2-macroglobulin receptor/low density lipoprotein receptor-related protein is increased in reactive and neoplastic glial cells

alpha 2-Macroglobulin receptor/low density lipoprotein receptor-related protein (alpha 2M-R/LRP) is a multi-functional cell-surface receptor that has been implicated in diverse physiologic processes. In normal human brain, alpha 2M-R/LRP is expressed principally by pyramidal neurons with localization to cell bodies and proximal processes. By contrast, alpha 2M-R/LRP is not present in either the cell bodies or processes of most normal macroglia (including astrocytes). In this investigation, we studied the expression of alpha 2M-R/LRP in the brain, following tissue injury or neoplastic transformation, by immunohistochemistry. Significantly increased alpha 2M-R/LRP immunoreactivity was identified in reactive astrocytes, indicating the expression of this receptor is regulated in vivo in response to brain injury. alpha 2M-R/LRP immunoreactivity was also detected in glial cell tumors; this finding is novel since malignant transformation is typically thought to turn off expression of this receptor.