Infratentorial ependymomas of childhood. Correlation between histological features, immunohistological phenotype, silver nucleolar organizer region staining values and post-operative survival in 16 cases

Immunohistochemical comparative analysis of GFAP, MAP - 2, NOGO - A, OLIG - 2 and WT - 1 expression in WHO 2016 classified neuroepithelial tumours and their prognostic value

Immunohistochemistry is routinely used in differential diagnosis of tumours of the central nervous system (CNS). The latest 2016 WHO 2016 revision now includes molecular data such as IDH mutation and 1p/19q codeletion thus restructuring glioma classification. Direct comparative information between commonly used immunohistochemical markers for glial tumours GFAP, MAP - 2, NOGO - A, OLIG - 2 and WT - 1 concerning quality and quantity of expression and their relation to the new molecular markers are lacking. We therefore compared the immunohistochemical staining results of all five antibodies in 34 oligodendrogliomas, 106 ependymomas and 423 astrocytic tumours. GFAP expression was reduced in cases with higher WHO grade, oligodendroglial differentiation and in IDH wildtype diffuse astrocytomas. By contrast MAP - 2 expression was significantly increased in diffuse astrocytomas with IDH mutation, while NOGO - A expression was not associated with any molecular marker. WT - 1 expression was significantly decreased in tumours with IDH mutation and ATRX loss. OLIG - 2 was increased in IDH-mutant grade II astrocytomas and in cases with higher proliferation rate. In univariate survival analysis high WT - 1 expression was significantly associated with worse outcome in diffuse astrocytic tumours (log rank p < 0.0001; n = 211; median time: 280 days vs 562 days). None of the markers was prognostic in multivariate survival analysis. Among the evaluated markers MAP - 2, OLIG - 2 and WT - 1 showed the best potential to separate between glioma entities and can be recommended for a standardized immunohistochemical panel.

A case of multinodular high-grade neuroepithelial tumor with ependymal differentiation

We describe a rare case of multinodular cerebral neuroepithelial tumor with ependymal differentiation. A 65-year-old man experienced loss of consciousness with an obscure episode of seizure attack. Magnetic resonance images disclosed a lesion located in the left temporal lobe and the insular cortex. The tumor was partially removed. Histologically, the tumor showed infiltrating multinodular tumor nodules in the cerebrum. Each nodule was well demarcated and composed of clear cells with perinuclear halos, intermingled fibrillary cells, and poorly differentiated neuroepithelial cells with mitotic activity. Immunohistochemically, clear cells showed dot-like positivity for epithelial membrane antigen. Fibrillary cells were positive for vimentin and nestin, whereas only a few glial fibrillary acidic protein-immunopositive cells were seen. We conclude that this tumor, being microscopically characterized by multinodular tumor nodules, was a high-grade neuroepithelial tumor with ependymal differentiation.

Demonstration of disturbed activity of the lateral amygdaloid nucleus projection neurons in depressed patients by the AgNOR staining method

BACKGROUND

The aim to find a morphological biomarker of disturbed activity of the lateral amygdaloid nucleus in depression was approached by a karyometric analysis of projection neurons.

METHODS

The study was performed on paraffin-embedded brains from 19 depressed patients from both the major depressive disorder (MDD) and the bipolar disorder (BD) diagnostic groups, including 10 suicides, and 24 matched controls. The karyometric parameters of the lateral amygdaloid nucleus (La) projection neurons bilaterally were evaluated by the argyrophilic nucleolar organiser region (AgNOR) silver staining method.

RESULTS

An increased AgNOR number was found in the right La in suicides compared to controls. The intra-group comparisons between the hemispheres suggest a disturbed amygdaloid lateralisation in depressed patients. The effects were independent from psychotropic medication. There was a strong positive correlation between the nuclear area in La projection neurons and prefrontal limbic areas pyramidal neurons in the right hemisphere specific for suicide and MDD.

LIMITATIONS

A major limitation of this study is the relatively small number of cases. A further limitation is given by the lack of data on drug exposure across the entire lifespan.

CONCLUSION

The results suggest that depressed patients from both the MDD and BD diagnostic groups exhibit an increased activity of the La output neurons specific for suicidal patients. The distinctness of the diagnostic groups of mood disorders was accentuated in the correlation analysis. This putative hyperactivity was specific for the right hemisphere and psychotropic medication most likely did not counteract it.

Stereotactic radiosurgery for pediatric recurrent intracranial ependymomas

OBJECT

To evaluate the role of stereotactic radiosurgery (SRS) in patients with recurrent or residual intracranial ependymomas after resection and fractionated radiation therapy (RT), the authors assessed overall survival, distant tumor relapse, progression-free survival (PFS), and complications.

METHODS

The authors retrospectively reviewed the records of 21 children with ependymomas who underwent SRS for 32 tumors. There were 17 boys and 4 girls with a median age of 6.9 years (range 2.9-17.2 years) in the patient population. All patients underwent resection of an ependymoma followed by cranial or neuraxis (if spinal metastases was confirmed) RT. Eleven patients had adjuvant chemotherapy. Twelve patients had low-grade ependymomas (17 tumors), and 9 patients had anaplastic ependymomas (15 tumors). The median radiosurgical target volume was 2.2 cm(3) (range 0.1-21.4 cm(3)), and the median dose to the tumor margin was 15 Gy (range 9-22 Gy).

RESULTS

Follow-up imaging demonstrated therapeutic control in 23 (72%) of 32 tumors at a mean follow-up period of 27.6 months (range 6.1-72.8 months). Progression-free survival after the initial SRS was 78.4%, 55.5%, and 41.6% at 1, 2, and 3 years, respectively. Factors associated with a longer PFS included patients without spinal metastases (p = 0.033) and tumor volumes < 2.2 cm(3) (median tumor volume 2.2 cm(3), p = 0.029). An interval ≥ 18 months between RT and SRS was also associated with longer survival (p = 0.035). The distant tumor relapse rate despite RT and SRS was 33.6%, 41.0%, and 80.3% at 1, 2, and 3 years, respectively. Factors associated with a higher rate of distant tumor relapse included patients who had spinal metastases before RT (p = 0.037), a fourth ventricle tumor location (p = 0.002), and an RT to SRS interval < 18 months (p = 0.015). The median survival after SRS was 27.6 months (95% CI 19.33-35.87 months). Overall survival after SRS was 85.2%, 53.2%, and 23.0% at 1, 2, and 3 years, respectively. Adverse radiation effects developed in 2 patients (9.5%).

CONCLUSIONS

Stereotactic radiosurgery offers an additional option beyond repeat surgery or RT in pediatric patients with residual or recurrent ependymomas after initial management. Patients with smaller-volume tumors and a later recurrence responded best to radiosurgery.

Demonstration of disturbed activity of external globus pallidus projecting neurons in depressed patients by the AgNOR staining method

BACKGROUND

The external globus pallidus (EGP) is thought to play the most important integrating and conveying role in the striatopallidal system involved in the transfer from motivation to action. The aim to find a morphological biomarker of disturbed EGP activity in depression was approached by the karyometric analysis of large projecting neurons.

METHODS

The study was performed on paraffin-embedded brains from 19 depressed patients from both the major depressive disorder (MDD) and the bipolar disorder (BD) diagnostic groups encompassing 10 suicides and from 24 controls. The karyometric parameters of EGP neurons bilaterally were evaluated by argyrophilic nucleolar organiser (AgNOR) silver staining method.

RESULTS

A significantly decreased AgNOR area was found in the left EGP neurons in depressed patients compared to controls. The distinctness of the diagnostic groups and suicidal vs non-suicidal patients was not shown in the statistical comparisons. The AgNOR parameter which was decreased correlated positively with the mean dose of benzodiazepines in non-suicidal patients.

LIMITATIONS

A major limitation of this study is the relatively small number of cases. A further limitation is given by the lack of data on drug exposure across the whole lifespan of patients.

CONCLUSION

The results suggest disturbed, most likely decreased, activity of the left EGP projecting neurons in depressed patients, a disturbed activity that should hypothetically be counteracted by the applied pharmacotherapy in non-suicidal patients.

Demonstration of disturbed activity of orbitofrontal pyramidal neurons in depressed patients by the AgNOR staining method

BACKGROUND

The aim to find the morphological biomarker of disturbed activity of the orbitofrontal cortex (OFC) in depression was approached by the karyometric analysis of pyramidal neurons.

METHODS

The study was performed on paraffin-embedded brains from 19 depressed patients from both major depressive disorder (MDD) and bipolar disorder (BD) diagnostic groups, including 9 suicides, and 24 matched controls. The karyometric parameters of medial OFC layer III and V pyramidal neurons bilaterally were evaluated by argyrophilic nucleolar organiser region (AgNOR) silver staining method.

RESULTS

The enlarged nuclear area was found in layer V pyramidal neurons in the right OFC in non-suicides compared to suicides and controls, which was most likely the effect of neuroleptics. The intra-group comparisons between the hemispheres suggest the disturbed orbitofrontal lateralisation in depressed patients (predominantly in suicides) with moderate distinctness of the MDD and the BD diagnostic groups.

LIMITATIONS

A major limitation of this study is a relatively small number of cases. A further limitation is given by the lack of data on drug exposure across the whole lifespan.

CONCLUSION

The results suggest disturbed activity of OFC pyramidal neurons in depression, distinct in suicide and the diagnostic groups of mood disorders. The non-suicidal patients seem to benefit from neuroleptics, which most likely increase the activity of the subpopulation of OFC pyramidal neurons.

Pediatric supratentorial ependymomas show more frequent deletions on chromosome 9 than infratentorial ependymomas: a microsatellite analysis

Numerous human malignancies, including brain tumors, have been reported to show aberrations on chromosome 9. In our previous screening study in ependymomas, we used microsatellite analysis to identify frequent aberrations on this chromosome. To refine our preliminary analysis of candidate regions, here we use 15 polymorphic microsatellite markers spanning the entire chromosome 9. A total of 48 pairs of matched normal and tumor specimens from patients with ependymoma, including 28 children (mean age, 4.4 years) and 20 adults (mean age, 44.9 years), were genotyped. Allelic imbalances were found in 30/48 patients (62.5%). Pediatric tumors, which were predominantly anaplastic, showed fewer aberrations (57.1%) than adult tumors (70%), and two common regions of deletions were identified (9p21.1 approximately p22.3 and 9q31.3 approximately q33.2). We found that 9q31.3 approximately q33.2, an approximately 8.5-megabase segment containing the DCR1 gene, exhibited the highest number of aberrations (n=33). Adults with ependymomas harboring aberrations on chromosome 9 (n=14) showed significantly longer overall survival than patients of the same group without this aberration (n=6; P=0.034), irrespective of the extent of resection in multivariate analysis. Aberrations of chromosome 9, and particularly of DCR1, may play a role in the prognostic evaluation for ependymomas in adults in the future. In pediatric patients, genetic aberrations were found significantly more often in supratentorial tumors than in tumors with infratentorial location (P=0.007). This result may underscore differences in the origin of these tumors.

Pediatric ependymoma: biological perspectives

Pediatric ependymomas are enigmatic tumors that continue to present a clinical management challenge despite advances in neurosurgery, neuroimaging techniques, and radiation therapy. Difficulty in predicting tumor behavior from clinical and histological factors has shifted the focus to the molecular and cellular biology of ependymoma in order to identify new correlates of disease outcome and novel therapeutic targets. This article reviews our current understanding of pediatric ependymoma biology and includes a meta-analysis of all comparative genomic hybridization (CGH) studies done on primary ependymomas to date, examining more than 300 tumors. From this meta-analysis and a review of the literature, we show that ependymomas in children exhibit a different genomic profile to those in adults and reinforce the evidence that ependymomas from different locations within the central nervous system (CNS) are distinguishable at a genomic level. Potential biological markers of prognosis in pediatric ependymoma are assessed and the ependymoma cancer stem cell hypothesis is highlighted with respect to tumor resistance and recurrence. We also discuss the shifting paradigm for treatment modalities in ependymoma that target molecular alterations in tumor-initiating cell populations.

Outcomes of malignant CNS ependymomas: an examination of 2408 cases through the Surveillance, Epidemiology, and End Results (SEER) database (1973-2005)

BACKGROUND

Determine the role of surgery and radiation therapy for patients with malignant CNS ependymomas.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database (1973-2005) was queried.

RESULTS

Overall, a total of 2408 cases of malignant ependymomas were identified. Of these, 2132 cases (88.5%) were identified as WHO grade II ependymomas and 276 cases (11.5%) as WHO grade III (anaplastic) ependymomas. The annual incidence of ependymomas was approximately 1.97 cases per million in 2005. Overall median survival for all patients was 230 mo, with a significant difference between women and men (262 mo versus196 mo, respectively) (P=0.004). Median age at diagnosis was 37 y among females and 34 y in males. Patients who successfully underwent surgical resection had a considerably longer median survival (237 mo versus 215 mo, P<0.001) as well as a significantly improved five-year survival (72.4% versus 52.6%, P<0.001). Univariate analysis demonstrated that age, gender, ethnicity, primary tumor site, WHO grade and surgical resection were significant predictors of improved survival for ependymoma patients. Multivariate analysis identified that a WHO grade III tumor, male gender, patient age, intracranial tumor locations and failure to undergo surgical resection were independent predictors of poorer outcomes. Multivariate analysis of partially resection cases revealed that lack of radiation was a sign of poor prognosis (HR 1.748, P=0.024).

CONCLUSION

Surgical extirpation of ependymomas is associated with significantly improved patient survival. For partially resected tumors, radiation therapy provides significant survival benefit.

Immunohistochemical prognostic markers in intracranial ependymomas: systematic review and meta-analysis

Distinction between grade II ependymomas and anaplastic ependymomas based on histopathological examination solely is problematic and, therefore, the management of intracranial ependymomas remains controversial. The aim of this study was to conduct a systematic review (SR) and meta-analysis (MA) of data published on immunohistochemical prognostic markers (IPM) in intracranial ependymomas (IE), and to establish an evidence-based perspective on their clinical value. Following the extensive search based on a strictly defined group of key words, 30 studies reporting results on IPM in IE were identified. Due to a pronounced inter-study heterogeneity, only 14 publications fulfilled the criteria for inclusion into SR. From the total of 67 immunohistochemical markers, 18 were found to correlate with prognosis. However, owing to inadequate data publishing, MA could be performed only with data on proliferation marker MIB-1 (Ki-67) from 5 publications, including 337 patients: The pooled hazard ratio for overall survival was 3.16 (95% confidence interval = 1.96-5.09; p < 0.001) implicating that patients suffering from tumors with higher immunohistochemical expression of MIB-1 had a significantly worse outcome. Marked inter-study heterogeneity and incomplete data publishing in primary studies significantly limited extent of the SR, and the possibility of performing MA. Although the prognostic impact of MIB-1 immunoexpression in IE could be confirmed, there remains lack of further reliable IPM that could be used in routine diagnosis. We encourage to search for new, useful markers, as well as to standardize lab-techniques and data interpretation algorithms across laboratories in order to increase data compatibility.

OUTCOME PREDICTORS FOR INTRACRANIAL EPENDYMOMA RADIOSURGERY

OBJECTIVE

To develop outcome predictors after stereotactic radiosurgery (SRS) in patients with intracranial ependymomas who had received previous fractionated radiation therapy, we compared tumor control, survival, and complications with tumor grade, volume, age of patients, and imaging characteristics.

METHODS

We retrospectively reviewed records of 39 consecutive ependymoma patients who underwent SRS for 56 tumors. The median patient age was 22.8 years (range, 2.9–71.1 years). All patients had previous surgical resection of their ependymomas followed by radiotherapy, and 14 patients underwent previous chemotherapy. Twenty-five patients had low-grade ependymomas (34 tumors), and 14 patients had anaplastic ependymomas (22 tumors). The median radiosurgery target volume was 3.6 cm3 (range, 0.1–36.8 cm3), and the median margin dose was 15.0 Gy (range, 10–22 Gy).

RESULTS

At a median of 23.5 months after SRS (range, 6.1–155.2 months), 25 patients died as a result of metastases (12 patients) or disease progression (13 patients). The overall survival rates after SRS were 60.1, 36.1, and 32.1% at 1, 3, and 5 years, respectively. The progression-free survival rates after SRS at 1, 3, and 5 years were 81.6, 45.8, and 45.8%, respectively, for all grades of ependymomas. Lower histological tumor grade was not significantly associated with better progression-free survival (P = 0.725). Factors associated with an improved progression-free survival included smaller tumor volume and homogeneous tumor contrast enhancement in low-grade ependymomas.

CONCLUSION

SRS provides another management option for patients with residual or recurrent ependymomas that have failed surgery and radiation therapy. Predictors of response include smaller volume and homogeneous contrast enhancement.

Demonstration of decreased activity of dorsal raphe nucleus neurons in depressed suicidal patients by the AgNOR staining method

BACKGROUND

Suicide and depression are closely related yet distinct phenomena. In both these phenomena, research has focused on central serotonergic system disturbances. The dorsal raphe nucleus (DRN) is the main source of serotonergic innervation of limbic structures crucial for the regulation of emotionally influenced behaviour.

METHODS

The study was carried out on paraffin-embedded brains from 23 depressed patients (12 suicides and 11 non-suicides) and 26 matched controls without mental disorders. The karyometric parameters of DRN neurons were evaluated by the AgNOR silver staining method.

RESULTS

The significant effect of suicide on the nuclear area was found in the cumulative analysis of all DRN subnuclei (ANOVA, P=0.032). A decreased mean value of this parameter was observed in the suicides group versus controls (t-test, P=0.032). This effect was especially pronounced in the violent suicide victims (t-test, P=0.001), who also demonstrated a decreased AgNOR area versus controls (t-test, P=0.007). No significant effect of depression or polarity on AgNOR parameters was found.

LIMITATIONS

A major limitation of this study is relatively small case number. A further limitation is given by the lack of data on drug exposure across the whole life span.

CONCLUSION

Our findings suggest that hypoactivity of DRN neurons is a distinct phenomenon in depression, specific only for suicidal subgroup of depressed patients.

The changes of AgNOR parameters of anterior cingulate pyramidal neurons are region-specific in suicidal and non-suicidal depressive patients

The anterior cingulate cortex (AC) is consistently implicated in the pathophysiology of depression. While suicide has been shown in previous reports to be closely related to depression, it is still a distinct phenomenon. The aim to differentiate between depression and suicide was approached by the karyometric analysis of AC pyramidal neurons. The study was performed on paraffin-embedded brains from 20 depressive patients (10 of whom had committed suicide) and 24 matched controls. The karyometric parameters of the layer III and V pyramidal neurons of the dorsal and ventral AC were evaluated bilaterally by Argyrophilic Nucleolar Organiser (AgNOR) silver staining method. Control-specific was the increased nuclear area in ontogenetically younger pyramidal neurons layer III in the left dorsal compared with ventral AC (Wilcoxon test, P<0.01). The decreased AgNOR number per nucleus in these cells in the right ventral AC was depression-specific compared with controls (t-test, P=0.047). On the other hand, the diffuse decrease in AgNOR ratio throughout pyramidal neurons on the left side was specific for suicidal depressive patients compared with non-suicidal patients and controls (ANOVA, P=0.028). The results suggest that regionally differentiated depression- and suicide-specific disturbed function of the most important AC output cells exists in depressive patients.

The changes in AgNOR parameters of dorsal raphe nucleus neurons are related to suicide

Depression has been established as the main cause of suicide and the research has concentrated on disturbed central serotonergic system in both disorders. The dorsal raphe nucleus (DRN) of brain stem is the main source of serotonergic innervation of limbic structures fundamental in the regulation of emotionally influenced behavior. The study was carried out on paraffin-embedded brains from 10 depressive patients, among them 5 suicides and 5 non-suicides and 13 matched mentally healthy controls. The karyometric parameters of DRN neurons were evaluated by AgNOR (Argyrophilic Nucleolar Organizer) silver staining method. The significant effect of suicide on nuclear area and AgNOR-ratio found in the cumulative analysis of all DRN subnuclei could be relevant for forensic diagnostic. The results suggest DRN neurons hypoactivity specific for suicide. Whether observed phenomenon is a "common trait" existing also in other diagnostic groups of mental disorders remains an open question.

Épendymomes intracrâniens de l'adulte. Diagnostic histologique et facteurs histopronostiques

BACKGROUND

Intracranial ependymomas are rare in adults and histopathological prognostic factors are poorly determined.

PURPOSE

A retrospective multicentric study was conducted in France in order to assess the prognostic value of histology.

MATERIAL

Between 1990 and 2004, 216 adult patients with newly diagnosed ependymomas were treated in 19 French centers. Eligibility required institutional histopathological confirmation of an ependymoma and available clinical history and MRI features (see comparison paper).

METHODS

Histological preparations and one paraffin embedded block from each patient were sent to Pr D. Figarella-Branger in Marseille. Central review by four neuropathologists (D. Figarella-Branger, A. Maues de Paula, C. Fernandez and A. Jouvet) was performed. Specimens for which all pathologists agreed with the histological diagnosis of ependymomas were included, whereas cases for which all disagree were excluded and reclassified. In the event of doubt and/or discrepancies between pathologists immunostaining was performed in order to reach a consensus diagnosis. Diagnostic of ependymomas was confirmed in 121 cases (56%). In theses cases, ependymomas were classified according to the WHO system (subtype and grade). The potential prognostic value (overall survival OS and disease free survival DFS) of the following histological parameters was examined: perivascular pseudorosettes, ependymal rosettes, hyalinized vessels, mitotic index, microvascular proliferation, necrosis, area of increased cellularity, nuclear atypia, brain invasion and Mib-1 labelling index.

RESULTS

Among the 121 ependymomas, 88 were grade II (47 classic, 17 cellular, 2 papillar, 6 clear cells and 16 tanicytic) and 33 grade III. WHO grading, occurrence of microvascular proliferation, necrosis, nuclear atypia and high proliferative index were correlated with both OS and DFS. Moreover, quantification of certain parameters enabled a reproducible grading system correlated with both OS and DFS.

Prognosis-related histomorphological and immunohistochemical markers in central nervous system tumors of childhood and adolescence

Brain tumors account for approximately 20% of all childhood cancers, and are the leading cause of cancer morbidity and mortality among children. Although numerous demographic, clinical and therapeutic parameters have been identified over the past few years that have significant prognostic bearing for some pediatric brain tumors, predicting the clinical course and outcome among children with central nervous system tumors is still difficult. A survey of publications on prognosis-related histopathological and immunohistochemical features among pediatric brain tumors revealed 172 series, of which 91 presented statistically significant outcome-associated parameters as defined by a P value of less than 0.05. Most investigations revealing significant prognosis-related markers were performed on medulloblastomas (30 publications), ependymomas (25) and astrocytic tumors (18). In total, 16 cohorts consisted of more than 100 cases (5 on ependymomas, 3 each on medulloblastomas and astrocytic tumors). On the other hand, there were also 13 series with fewer than 20 cases (5 on medulloblastomas). Potentially prognostic histopathological markers vary among different entities and consist of assessment of necroses, mitoses, differentiation, vascular proliferation, and growth pattern, whereas immunohistochemical features include proliferation markers (Ki-67, MIB-1), expression of oncogenes/tumor suppressor genes and their proteins (TP53, c-erbB2), growth factor and hormonal receptors (VEGF, EGFR, HER2, HER4, ErbB-2), cell cycle genes (p27, p14ARF) and cell adhesion molecules, as well as factors potentially related to therapeutic resistance (DNA topoisomerase IIalpha, metallothionein, P-glycoprotein, tenascin). This review discusses the prognostic potential of histopathological and immunohistochemical markers that can be investigated by the practicing neuropathologist as part of the routine diagnostic workload, and scrutinizes their benefit for predicting therapy response and patient outcome among children with brain tumors.

Light microscopic demonstration of the microlumen of ependymoma: A study of the usefulness of antigen retrieval for epithelial membrane antigen (EMA) immunostaining

To determine the origin of dotlike epithelial membrane antigen (EMA) immunoreactivity of ependymoma, which is consistent with the eosinophilic globular body in hematoxylin and eosin (H&E) stain, an immunoelectron microscopic study was undertaken. The usefulness of antigen retrieval pretreatment in detecting the dotlike EMA immunoreactivity in ependymomas was also studied. The materials were 29 ependymomas, 7 autopsy brains as a normal control, and 50 brain tumors of various types. The study confirmed that most of the brown dots in EMA immunostain in ependymoma represented microlumina of tumor cells. In ependymomas, plain EMA immunostaining showed dotlike positivity in only six cases (21%), and antigen retrieval pretreatment increased the number of positives up to 26 cases (90%). Antigen retrieved CD99 detected 23 positive cases (80%) in ependymomas. On the basis of the results, although some false positive findings were raised by antigen retrieval pretreatment, the authors positively recommend adoption of the technique, especially when ependymoma remains as one of the differential diagnoses of the tumor.

Immunohistochemical markers for prognosis of ependymal neoplasms

Intracranial ependymomas are the third most common primary brain tumor in children. Although clinical and histological criteria for ependymoma prognosis are recognized, studies have reported contradictory results. Prognostic significance based on immunohistochemistry of ependymomas has been reported in a few studies. One-hundred and twelve patients with intracranial ependymomas were examined retrospectively for immunoexpression of various tumor-associated antigens and apoptosis. The results demonstrated significant preponderance of expression of the tenascin, vascular endothelial growth factor protein (VEGF), epidermal growth factor (EGFR) and p53 protein in high-grade tumors. Also high-grade ependymomas revealed more prominent labeling indices (LI) for proliferative marker Ki-S1 and apoptotic index (AI), and lower LI for cyclin-dependent kinase inhibitors p27/Kipl and pl4ARF. For low-grade ependymomas the progression-free survival time (PFS) was found to be significantly shorter for Ki-S1 LI > 5%, and for tenascin, VEGF and EGFR positivity. For high-grade ependymomas PFS was found to be significantly reduced for p27 LI < 20%, p14ARF LI < 10%, for p53 positivity, and for AI < 1%. The CART modeling process exhibited five final groups of ependymoma patients (1) low-grade and tenascin-negative; (2) low-grade and tenascin-positive; (3) high-grade and p53-negative with p14 LI > 0%; (4) high-grade with combination of either p53 positivity and p14 LI > 10% or p53 negativity and p14 LI < 10%; (5) high-grade and p53-positive with pl4 LI < 10%. In summary, some immunohistochemical variables were found to be the strong predictors of ependymoma recurrence and they seem to be useful for assessing individual tumor prognosis in routinely processed biopsy specimens together with tumor grade. For histologically benign ependymomas immunohistochemical study should be focused on Ki-S1, tenascin, EGFR and VEGF evaluation, whereas p53 expression and number of p27, p14 and ISEL-positive nuclei will be of value in determining PFS from high-grade ependymomas.

Antineuronal nuclei immunohistochemical staining patterns in childhood ependymomas

NeuN, the mouse-derived monoclonal antibody to the reportedly neuron-specific nuclear protein, has been observed to react with many different types of normal, postmitotic neurons throughout the central and peripheral nervous systems. We retrospectively examined 23 surgical specimens (collected from 20 patients) originally diagnosed at our institution between 1983 and 1999 as ependymoma (9), myxopapillary ependymoma (1), anaplastic/malignant ependymoma (10), and primitive neuroectodermal tumor with ependymal differentiation (3). The ependymomas included lesions from the spine (3), cerebrum (5), and posterior fossa (15). Representative formalin-fixed, paraffin-embedded sections from each tumor were subjected to immunohistochemical staining with antibody against NeuN (Chemicon International, Inc, Temecula, CA). Five astrocytomas, four primitive neuroectodermal tumors, and normal cerebral cortex and ependyma from autopsy brains of premature newborns, term infants, and older children served as controls. Thirteen ependymal tumors had positive nuclear staining ranging from rare tumor cells to numerous groups of cells; of these, 9 were anaplastic ependymomas and had the most staining. These studies suggest that some ependymomas arise from a pluripotential neuroglial cell.

A clinicopathologic study of 81 patients with ependymomas and proposal of diagnostic criteria for anaplastic ependymoma

Optimal histologic criteria for the classification of and grading of ependymomas, including their anaplastic forms, remain elusive. This is especially true because of the poor correlation of these criteria with clinical outcome. The aim of this study was to identify the histopathologic parameters that could distinguish different prognostic groups of patients with ependymomas. Eighty-one patients with ependymal tumors, including those originally diagnosed ependymomas, anaplastic ependymomas and myxopapillary ependymomas, were enrolled in this study. Thirteen histologic parameters, including hypercellularity, nuclear pleomorphism, mitoses, endothelial proliferation, necrosis, clear cell, thrombi, dystrophic calcification, psammoma bodies, bone, cartilage, Rosenthal fibers and MIB-1 labeling index (LI), were evaluated in each patient and correlated with clinical outcome. We assigned one score for each histopathologic parameter evaluated and used a stepwise selection method with entry model based on the significance of the log-rank statistic to formulate a scoring model. Four parameters were chosen in this process, including mitoses > or = 4/10 hpf (1.7/mm2), hypercellularity, endothelial proliferation and necrosis. The sum of these four parameters (scores) was the histopathologic score of the tumor. The progression-free survival (PFS) and overall survival (OS) of patients with histopathologic scores 0 and 1 were significantly better than those with histopathologic scores 2, 3 and 4 (p < 0.001 and p = 0.005, respectively). Because of the latter finding, we proposed that anaplastic ependymoma could be diagnosed by the presence of any two of the aforementioned four parameters. Multivariate analyses including clinical and histopathologic variables showed that histopathologic score > or = 2 and subtotal resection were the factors related to increased risk of recurrence, while histopathologic score > or = 2 was the only factor related to overall survival. Based on the above findings, we concluded that histopathology is an important prognostic indicator for patients with ependymomas.

Prognostic factors in intracranial ependymomas in children

OBJECT

The occurrence of intracranial ependymomas in children is relatively infrequent, and their prognostic factors are still controversial, especially regarding histological composition.

METHODS

A retrospective study was conducted of 37 children treated during the last 20 years for intracranial ependymomas at the Hôpital de la Timone. Both univariate and multivariate statistical analyses were performed to assess the prognostic relevance of patient age and sex, extent of tumor removal, location of the tumor (supratentorial compared with infratentorial, median compared with lateral), tumor histological composition, and adjuvant therapies in affecting the 5-year progression-free survival (PFS) rate and overall survival (OS) rate. The following histopathological features, either alone or in combination, were analyzed: endothelial proliferation, necrosis, loss of differentiating structures (present compared with absent), the number of mitotic figures per 10 hpf, and cellularity (number of nuclei/5 hpf). In addition, immunohistochemical detection of Ki-67 antigen was performed and the Ki-67 labeling index (LI) evaluated in all cases. The 5-year OS and PFS rates were 45% and 25%, respectively (median follow up 34 months). Four patients died of disease without remission (median 163 days) and disease in 21 patients relapsed: 18 in situ and three both in situ and distantly. On univariate analysis total surgical resection and median infratentorial location were associated with a better outcome (p < 0.002) for both OS and PFS. Loss of differentiating structures was associated with poor prognosis (p < 0.008) and the combination of necrosis, endothelial proliferation, and mitotic index greater than 5 was also a negative predictive factor for both OS (p < 0.002) and PFS (p = 0.02). The PFS time was shorter in patients younger than 4 years of age and in patients in whom a Ki-67 LI greater than 1 was found (p = 0.03 and 0.006, respectively). Adjuvant radiotherapy and chemotherapy were not relevant to prognosis. Moreover, among the 15 patients in whom total excision was achieved, OS was better in those who did not receive adjuvant therapies. In contrast, adjuvant therapies significantly enhanced PFS time in patients in whom tumor excision was incomplete.

CONCLUSIONS

This study and analysis of the literature further highlight that total tumor removal is the treatment of choice for ependymomas in children. Postoperative measurement of residual tumor is required, especially because a subgroup of patients might be treated by surgery alone. Median infratentorial ependymomas have to be distinguished from the lateral type. Appropriate and reproducible histological parameters and Ki-67 LI are of interest as predictors of outcome.

Prognostic relevance of AgNORs in tumor pathology

The importance of the analysis of the silver-stained nucleolar organizer regions (AgNORs) for prognostic purposes in tumor pathology has been reviewed. Current available data from the literature demonstrate that the evaluation of the quantity of interphase AgNORs is an independent prognostic factor in several types of human tumors. Results of our investigations indicate that AgNORs are the most powerful variable predicting survival in patients with pharyngeal carcinoma, multiple myeloma, male breast and prostate carcinoma. The combination of AgNOR counts and histologic pattern allows the stratification of patients with multiple myeloma, pharyngeal and prostate carcinoma into low- and high-risk groups, which could benefit from different therapy. Moreover, AgNOR analysis predicts response to treatment in adult patients with acute myelogenous leukemia, and appears as an independent prognostic factor in a prospective study on renal cell carcinoma. Therefore, AgNOR analysis is a really important prognostic factor for several human neoplasias. The experimental and theoretical justifications for AgNORs as a prognostic factor are also reviewed, in particular the strict correlation between AgNOR quantity and tumor cell doubling time. Lastly, the lack of prognostic significance of AgNOR analysis in some circumstances is critically discussed.

The immunophenotype of ependymomas

The morphologic distinction of ependymomas with epithelial cytology from metastatic carcinoma may pose a significant problem in differential diagnosis. The known presence of keratin in glioma cells further complicates the issue. Using the labeled streptavidin-biotin method with automated staining, we studied epithelial and glial marker expression in 52 ependymomas of varying type and grade, including 20 epithelial-appearing, 14 glial-appearing, eight mixed pattern, and 10 myxopapillary tumors; 38 were low grade and 14 anaplastic. All tumors were immunoreactive for glial fibrillary acidic protein (GFAP), and S-100 protein. Diffuse staining for GFAP was noted in glial-appearing ependymomas featuring perivascular pseudorosettes. Diffuse immunostaining for S-100 protein was seen in cellular lesions exhibiting epithelial-like features. Staining was more diffuse for GFAP than S-100 protein in anaplastic ependymomas. Keratin (AE1/AE3) reactivity was seen in 98% of cases, the pattern being similar to that of GFAP. The frequency of staining for other keratins varied: wide-spectrum keratin (35%), cytokeratin (CK)7 (20%), CAM 5.2 (19%), CK903 (14%), and CK20 (8%); as a rule, it was scant and limited to occasional cells and processes. epithelial membrane antigen (EMA) staining was seen in 36% of all cases and in 67% of epithelial-appearing tumors wherein it often high-lighted microlumina. Aside from AE1/AE3 staining and very infrequent wide-spectrum keratin and EMA reactivity, expression of epithelial markers was not seen in anaplastic ependymomas. No carcinoembryonic antigen (CEA) positivity was noted in any case. Collagen IV reactivity was limited to tumor cell-stroma interfaces. Although variable, S-100 protein and GFAP staining is seen in all ependymomas, particularly in true and perivascular pseudorosettes. Widespread reactivity for keratin AE1/AE3 corresponds closely to the pattern of GFAP staining. Significant staining for other keratins or for CEA is inconsistent with a diagnosis of ependymoma. EMA reactivity is largely limited to luminal staining of rosettes and tubules.

Clinicopathologic study of 61 patients with ependymoma including MIB-1 immunohistochemistry

Predicting behavior based on histologic appearance has been problematic in ependymomas. Sixty-one patients with ependymoma (excluding subependymoma and myxopapillary ependymoma) were studied. The patients included 36 men and ranged in age from 1.5 to 74 years (median, 33 years). The most common clinical presentations included headache (n = 19), weakness (n = 18), nausea/vomiting (n = 12), and gait disturbance (n = 10). Location included spinal cord (n = 24), fourth ventricle (n = 21), lateral ventricle (n = 8), and third ventricle (n = 5). Initial surgery included a gross total resection of tumor in 22 patients and subtotal resection or biopsy in the remaining patients. Thirty-five patients were known to have been treated with adjuvant radiation therapy and 13 patients received adjuvant chemotherapy. At last known follow-up, 20 patients were alive with no evidence of tumor (median, 66.5 months), 17 patients were alive with residual tumor (median, 14 months), and 12 patients died of tumor (median, 27.5 months). Two additional patients are alive with tumor status not known, two cases are current, and two patients were lost to follow-up. The additional six patients died either shortly after surgery or of surgical complications. Sixteen of 18 patients had at least one tumor recurrence at median 28.5 months. Fifty-one tumors had a predominantly glial pattern and 10 had a mixed glial-epithelial pattern. Of histologic features examined, patients with tumor recurrence or who died of tumor more frequently had observable mitotic figures, vascular proliferation, necrosis, and foci of increased cellularity. Eight of 18 recurrent tumors were classified as high grade ependymomas (anaplastic/malignant). Of patients who died of tumor, 4 of 12 had histologically high grade tumors versus 5 of 39 of the remaining tumors. MIB-1 immunostaining (marker of cell proliferation) was performed on 50 tumors. MIB-1 labeling indices (% positive tumor cell nuclei) ranged from 0.1 to 34.0 (median, 1.1). A higher percentage of patients with recurrent tumor (6 of 13, 46%) or who died of tumor (3 of 10, 30%) had MIB-1 indices >/= 4.0 versus the remaining patients (8 of 33, 24%). The conclusions are as follows: (1) histologic appearance and MIB-1 indices were not reliably predictive of tumor behavior, probably due in part to tumor heterogeneity; (2) tumors with two or more of the following features: identifiable mitotic figures, hypercellularity, vascular proliferation, and necrosis were more likely to behave in an aggressive manner; and (3) elevated MIB-1 labeling indices (>/=4.0 in this study) were encountered in a higher percentage of fatal and recurrent tumors than in nonfatal or nonrecurrent tumors.

Giant extra-axial cerebellopontine angle/cavernous sinus ependymoma: case report

OBJECTIVE AND IMPORTANCE

The presentation, diagnosis, and treatment are described for a patient with a giant ependymoma involving the right cerebellopontine angle extending into the cavernous sinus. This case presents the unusual occurrence of a large extra-axial intracranial ependymoma and is the first reported case of cavernous sinus extension of this tumor.

CLINICAL PRESENTATION

The patient was a 22-year-old woman who presented with a 3-day history of generalized headache and right-sided facial droop. Magnetic resonance imaging revealed a nonhomogeneously enhancing cystic mass that was primarily in the posterior fossa with significant supratentorial extension and no apparent intra-axial or intraventricular involvement.

INTERVENTION

Gross total resection of this mass was achieved via two-staged resections using an initial presigmoid transpetrous, transtentorial approach and a subsequent pterional craniotomy. Pathological evaluation confirmed the diagnosis of ependymoma, and adjuvant radiation therapy to the resection bed was administered.

CONCLUSION

Ependymomas can present as entirely extra-axial intracranial masses and rarely may involve the confines of the cavernous sinus.

Ependymomas: MIB-1 proliferation index and survival

The biologic behavior of ependymomas is highly variable, and its correlation with histologic features is at best imprecise. This retrospective study attempted to correlate the malignant histologic characteristics of ependymomas with MIB-1 proliferation index and survival. Biopsy and resection specimens taken from 34 patients who received treatment 1972 to 1996 were histologically examined. The patients' ages range was 1 to 59 years. The histologic specimens were assessed for anaplastic features (necrosis, mitosis, vascular proliferation, cellular pleomorphism, and overlapping of nuclei) and an MIB-1 (Ki-67 antigen) proliferation index was also determined. The overall median MIB-1 proliferation index was 7.8% (range 0.1 - 62.5%). An MIB-1 of 20% was significant for a decrease in survival (RR = 5.7) (p = 0.0013). The median MIB-1 for patients < 20 years old was 20.6% with range (0.1, 43%), while that for patients > 20 years was 5.1% (range 0.2, 9.4%) (KW p = 0.055). Three of 5 histological features evaluated were significantly associated with outcome: > 5 mitotic figures per high-power field, necrosis, and vascular proliferation, but not nuclear overlap or pleomorphism. All pathologic factors except pleomorphism were significantly related to the MIB-1 proliferation index. In brief, our data support the association of poor prognoses in ependymomas with young age, the presence of three to four anaplastic histologic features, and an MIB-1 proliferation index > 20%.

Expression of vascular endothelial growth factor and its receptors in the anaplastic progression of astrocytoma, oligodendroglioma, and ependymoma

Vascular endothelial growth factor (VEGF) is a hypoxia-inducible angiogenic factor, which is known to be upregulated in most cases of glioblastoma multiforme (GBM). The expression of VEGF and its receptors in ependymomas, oligodendrogliomas, and particularly the expression during anaplastic progression of these three types of gliomas has not been studied extensively. Fifty-six gliomas, consisting of 10 ependymomas, 12 oligodendrogliomas, 3 anaplastic oligodendrogliomas, 6 astrocytomas grade II, 5 anaplastic astrocytomas, and 20 glioblastoma multiformes, were investigated for VEGF and receptor expression using in situ hybridization (ISH) and reverse transcription polymerase chain reaction (RT-PCR). Results showed that VEGF was moderately to strongly expressed in 8 of 10 ependymomas and in all anaplastic oligodendrogliomas and glioblastoma multiforme cases. These tumors displayed similar degrees of extensive necrosis and vascular proliferation, with VEGF expression consistently seen in tumor cells around necrotic areas. The VEGF expression, although present at a lower level, also was shown in 4 of 12 oligodendrogliomas, in 3 of 6 astrocytomas grade II, and in 2 of 5 anaplastic astrocytomas, with a regional rather than diffuse pattern of positive result. The findings from the in situ hybridization study correlated with the expression index, as determined by reverse transcription polymerase chain reaction. Expression of VEGF was correlated significantly with vascular proliferation (p < 10(-5)) and necrosis (p < 10(-5)), as well as with microvessel density (p = 0.002, rs = 0.41). The VEGF receptors, kinase domain region (KDR) and Fms-like-tyrosine kinase (Flt-1), also were upregulated in the tumor vasculature of glioblastoma multiforme, anaplastic oligodendrogliomas, and ependymomas with necrosis, whereas the astrocytomas grade II, anaplastic astrocytomas, and oligodendroglioma tumors tended to express a weak to nondetectable signal. Anaplastic progression in all three types of gliomas is heralded by the occurrence of small zones of VEGF-expressing cells and early vascular proliferation, followed by an accelerated phase of angiogenesis closely associated with VEGF induction around areas of necrosis and with the expression of VEGF receptors in the tumor vasculature.

Intracranial ependymomas in children: a critical review of prognostic factors and a plea for cooperation

BACKGROUND

Current controversies in pediatric intracranial ependymoma include histologic categorization and management. Most of our knowledge of this disease comes from single-institution reports.

METHODS

A literature search was done, covering the period 1976-1996. The aim of this review is to analyze the prognostic factors reported in the literature over the last 20 years.

RESULTS

Forty-five series were reviewed, including more than 1,400 children. The largest series reported on 92 patients, and the accrual rate ranged from 0.32-12 patients per year. None of the prognostic factors reported achieved a consensus throughout the different series. Histology remains a major issue, and the range in the incidence of anaplastic ependymo mas (7-89%) highlights the difficulty in agreeing on a histological grading system. The role of surgery on the outcome seems to be determinant. Recent series based on homogeneous imaging-documented extents of resection strongly support the benefit of postoperative radiotherapy. The lack of a proven, effective chemotherapy regimen precludes its use except in prospective pilot studies.

CONCLUSIONS

Limited information is available from single-institution reports in ependymoma. Only large national or international studies can provide enough information to allow a multivariate analysis of the prognostic factors, and thus lead to new therapeutic proposals.

The molecular biology of ependymomas

Intracranial ependymomas are the third most common primary brain tumor in the pediatric population. Although an anaplastic variant is recognized, numerous studies examining the prognostic implications of histological features, such as necrosis, endothelial proliferation and mitoses, have yielded contradictory results. In order to improve outcome prediction in affected patients and to refine therapeutic decision-making, there is a strong need for identifying relevant biological correlates of tumor behavior. The molecular biology of tumors is a rapidly expanding field and includes investigations into cytogenetics, oncogenes, growth factors, growth factor receptors, hormonal receptors, proliferation markers, apoptosis, cell cycle genes and cell adhesion molecules, as well as factors potentially related to therapeutic resistance, such as the multidrug resistance gene. The molecular biology of astrocytic tumors in adults has been the subject of many studies; however, relatively few studies have been focused on ependymomas. Herein we review potential oncological markers in ependymomas that have been identified to date and highlight the limitations of our current knowledge as a basis for defining areas for future investigation.

[Ectopic intraspinal extradural anaplastic ependymoma in an infant]

BACKGROUND

Ependymomas represent about 10% of the spinal tumors in children. Some of them may be unusually located.

CASE REPORT

A 10-month-old boy was admitted for an abdominal mass syndrome with dehydration asthenia and acute bladder dysfunction. A few hours later, he developed a flaccid paraplegia. Ultrasonic and magnetic resonance spinal imaging showed a giant intraspinal tumor extending from T9 to IA level, posteriorly located to the dural compartment, widening the spinal cord. Ultrasonography also showed right ureterohydronephrosis due to the neurological bladder dysfunction. A conservative laminotomy-laminoplasty was performed in emergency. Total removal of the tumor that was attached to the right dorsal root was achieved extradurally, requiring resection of the proximal part of the root. Histological features were typical of malignant ependymoma. Chemotherapy was initiated 2 weeks later. The severe renal destruction and the persistent bladder dysfunction led to a heminephrectomy and a cystostomy, 3 weeks later. The neurological recovery was only partial with a follow-up of 18 months.

CONCLUSION

Ectopic intraspinal extradural localization of ependymomas is rare and their development from a nerve root is exceptional.

Intracranial ependymomas of childhood. Lack of correlation of histopathology and clinical outcome

The histopathology of 66 children with the diagnosis of ependymoma who were operated on at our institution between 1954 and 1994 were reviewed. We performed an initial analysis using the entire study cohort to determine which histopathological features associated with each other in a statistically significant fashion in an attempt to identify combinations of features that together might be useful in predicting outcome. A detailed outcome analysis was then performed on the 37 most recent cases who survived the postoperative period, in whom pre- and post-imaging studies as well as long term follow-up were obtained, in order to identify the histopathological features and combinations of features that were predictive of overall and progression-free survival. Five- and ten-year progression-free survivals were 45.1% and 36.1%, respectively. Overall survivals were 57.1% and 45.0%, respectively. Of the eight individual histopathological features, only the presence of necrosis was found to correlate with a less favorable overall and progression-free survival (PFS) (p = 0.06 and 0.03, respectively). In addition, the combination of necrosis with vascular proliferation or nuclear pleomorphism was associated with a worse PFS (p = 0.01 and 0.02, respectively). However, when other clinical predictive factors were included in a multivariate regression analysis, none of the histological features or combinations of features were independently associated with outcome. In addition, no relationship was found between the pattern of rosettes (true rosette, pseudorosette, or perivascular pseudorosette) and clinical outcome. In conclusion, although this study found an association between certain histopathological features and clinical outcome in children with ependymomas, these relationships did not reach statistical significance on multivariate analysis and, thus, do not provide sufficient evidence for modifying therapy based on histopathology alone.

Differential expression of cell adhesion molecules (CAM), neural CAM and epithelial cadherin in ependymomas and choroid plexus tumors

A series of frozen specimens of 18 ependymomas and 7 choroid plexus tumors were examined for their expression of cell adhesion molecules, such as neural cell adhesion molecule (NCAM), its polysialylated isoforms (PSA NCAM), and epithelial (E-) cadherin, and of intermediate filament proteins, such as glial fibrillary acidic protein (GFAP) and cytokeratin, using various monoclonal and polyclonal antibodies. Normal choroid plexus and ependyma were taken as controls. Anti-E-cadherin immunoreactivity was observed on the basolateral part of most adult choroid plexus and benign choroid plexus papilloma cells. However, a small number of atypical papillomas and carcinoma cells showed anti- E-cadherin immunoreactivity throughout their cell surface membrane. NCAM were not expressed by adult choroid plexus and benign papilloma cells. Only a few cells expressed NCAM and PSA NCAM in developing choroid plexus, atypical papillomas and carcinomas. Cytokeratin expression was always observed in choroid plexus and their tumors; GFAP expression was variable from case to case. In contrast, ependymal cells and their tumors never expressed E-cadherin but strongly expressed NCAM. PSA NCAM was found in ependymomas exhibiting anaplastic features. All ependymomas strongly expressed GFAP and a few demonstrated slight expression of cytokeratin. These data suggest that, besides GFAP and cytokeratin, NCAM and E-cadherin are of potential diagnostic value in distinguishing choroid plexus tumors from ependymomas. E-cadherin and NCAM may play a role in the functional organization of normal choroid plexus and ependyma, respectively. In particular, incomplete or irregular anti-E-cadherin expression in choroid plexus tumors and PSA NCAM immunoreativity in ependymomas and choroid plexus tumors correlates with the emergence of anaplastic histological features.

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

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