Rosette-forming glioneuronal tumor of the fourth ventricle. Two cases report and literature review. / Tumor glioneuronal formador de rosetas del IV ventrículo. Presentación de 2casos y revisión de la literatura.

Rosette-forming glioneuronal tumor of the fourth ventricle is a primary central nervous system tumor introduced in the group of glioneuronal tumors in the WHO classification of 2007. Initially it was described around the fourth ventricle, but recently have been published cases in different locations. We present 2cases of this rare tumor, both surgically treated. The first in a 41 year old man with typical symptoms of posterior fossa injury. The second in an 18 year old woman, with incidental finding of posterior fossa injury that was also surgically treated. We present pre- and post-surgical magnetic resonance images, histological pictures of this tumor and we make a review of the literature.

Chordoid Glioma of Third Ventricle With an Epidermoid Cyst: Coexistence or Common Histogenesis?

Chordoid glioma (CG) is a World Health Organization classified grade II tumor located exclusively in the region of anterior third ventricle. Association of CG with other lesions is extremely rare. We report a case of CG in a 45-year-old male coexisting with an epidermoid cyst in the third ventricle. Ultrastructural examination of the CG revealed microvilli, junctional complexes, and intermediate filaments within the cytoplasm suggesting origin from specialized ependyma. The association of the 2 lesions appears coincidental as convincing evidence for a common histogenesis was not found.

Three-dimensional reconstructive analysis of intracytoplasmic lumina found in ependymomas.

Three-dimensional reconstructive analyses revealed that the intracytoplasmic lumina found in ependymomas were actually formed by subsidence of an extracellular membrane, resembling a volcano. This finding was compatible with cytologic and electron microscopic findings. In addition, there were many tiny thorns resembling a holly leaf on the extracellular membrane, such that cilia and microvilli on the cellular membrane discontinued cell-to-cell tight junctions.

Ultrastructural evidence of ependymal differentiation in a genetically proven atypical teratoid/rhabdoid tumor.

INTRODUCTION: We describe a case of genetically proven atypical teratoid/rhabdoid tumor (ATRT), showing ultrastructural evidence of ependymal differentiation. Such differentiation has not been reported so far in ATRT. CONCLUSION: This finding supports the concept that ATRTs as the majority of central nervous system embryonal tumors may derive from an immature and pluripotent neuroectodermal cell capable of differentiating along multiple lineages.

Chordoid glioma of the third ventricle: a report of two cases, one with ultrastructural findings.

Chordoid glioma, which generally occurs in adults, is a rare CNS tumor arising in the anterior part of the third ventricle. We report two cases of chordoid glioma of the third ventricle in a 42-year-old woman and a 51-year-old man, respectively. Both tumors showed essentially the same histological and immunohistochemical features; the tumors were composed of cords and nests of epithelioid, GFAP-immunoreactive cells in a mucinous stroma with lymphoplasmacytic infiltrates at the tumor periphery. Ultrastructural examination in one case revealed that the tumor cells were characterized by the presence of hemidesmosomes and associated focal basal lamina formation, intermediate junctions, microvilli and cilia, and intercellular microrosettes with microvilli. Of interest was that small blood vessels with fenestrated endothelial cells were present in the stroma. In the brain, the presence of fenestrated endothelial cells is a feature of the circumventricular organs (except the subcommissural organ), among which the organum vasculosum of the lamina terminalis is located in the anterior part of the third ventricular floor that is lined by specialized ependymal cells known as tanycytes. These findings further strengthen the hypothesis that chordoid glioma may represent a peculiar clinicopathological subtype of ependymoma (chordoid ependymoma) originating from the lamina terminalis area.

Subependymal giant cell astrocytoma (SEGA): Is it an astrocytoma? Morphological, immunohistochemical and ultrastructural study.

Subependymal giant-cell astrocytoma (SEGA) is a rare intra-ventricular low-grade tumor which frequently occurs as a manifestation of tuberous sclerosis complex. The histogenesis of SEGA is controversial and its astrocytic nature has been doubted. First studies suggested the astrocytic nature of SEGA while several recent reports demonstrate its glio-neuronal nature. In spite of this, in the recently revised WHO classification of the CNS tumors, SEGA has been still included in the group of astrocytomas. We studied nine tuberous sclerosis complex-associated SEGAs. Patients were 1-18 years old. Eight patients (89%) had a solitary lesion located in the lateral ventricle close to of the head of the caudate nucleus, the remaining patient (11%) had two tumors, one located close to the head of the left caudate nucleus and the other in the central part of the right lateral ventricle. Histologically, tumors were composed of three types of cells: spindle, gemistocytic and ganglion-like. Four tumors (44%) had a prominent vascularization and three (33%) showed an angiocentric pattern. Calcifications were observed in six cases (66%). By immunohistochemistry, the majority of the tumors were GFAP- (9; 100%), neurofilament- (8, 89%), neuron-specific enolase- (9, 100%), and synaptophysin- (8; 89%) positive. Ultrastructural studies were performed on four cases. In all four there were glial cell processes filled with intermediate filaments. In one case dense core putative neurosecretory granules were appreciable. Our results emphasize the glio-neuronal nature of SEGA. We suggest moving it into the group of mixed glio-neuronal tumors under the denomination of subependymal giant cell tumor.

Ultrastructural study of neuronal and related tumors in the ventricles.

Intraventricular tumors may arise from a variety of cells in the region. There are some difficulties in diagnosing these tumors because of their histologically similar appearance. We analyzed intraventricular tumors, including central neurocytoma, oligodendroglioma, cerebral neuroblastoma, and cerebellar neuroblastoma, the neuronal characters of which were established based on their ultrastructural findings, except for oligodendroglioma. Central neurocytoma and cerebellar neuroblastoma showed synaptic formation, and cerebral neuroblastoma possessed immature neurites. Oligodendroglioma showed similar structures to that of a normal oligodendrocyte. Furthermore, we review the literature and evaluate the usefulness of analyzing ultrastructures.

Medulloblastoma demonstrating multipotent differentiation: case report.

We report a 6-year-old boy who presented with a medulloblastoma demonstrating classic, myoblastic, neuronal, glial, and melanotic differentiation and manifesting as severe morning headache. Magnetic resonance imaging revealed a mass lesion with cystic components in the cerebellar vermis. He underwent suboccipital craniotomy and total resection of the tumor. The specimen consisted of three morphologically distinct components. The first component consisted of densely packed cells with round-to-oval highly hyperchromatic nuclei surrounded by scanty cytoplasm. Immunohistochemical staining revealed diffuse expression of neurofilament protein and focal expression of desmin and myoglobin. The second component consisted of long spindle-shaped cells with elongated nuclei and eosinophilic cytoplasm. Immunohistochemical staining revealed diffuse expression of neurofilament protein, desmin, and myoglobin. The third component consisted of cells with small, densely hyperchromatic nuclei and scanty cytoplasm in a fine fibrillary background. Mature ganglion cells and melanotic tumor cells were also observed. Immunohistochemical staining revealed diffuse expression of synaptophysin and neurofilament protein, and focal expression of glial fibrillary acidic protein, S-100 protein, desmin, and myoglobin. The diagnosis was medulloblastoma with myoblastic, neuronal, astrocytic, and melanotic differentiation. Medulloblastoma demonstrating multipotent differentiation is rare, but the features observed in this case support the idea that medulloblastoma originates from multipotent stem cells.

Central neurocytoma: report of two cases

INTRODUÇÃO: Neurocitoma central é um tumor neuroectodérmico raro, geralmente localizado nos ventrículos laterais. RELATO DE CASOS: Uma mulher de 26 anos e um homem de 33 anos apresentaram-se com hipertensão intracraniana. Exames de imagem revelaram tumor intraventricular heterogêneo, que impregnava por contraste, ocupando os ventrículos laterais e causando hidrocefalia. A mulher faleceu no pós-operatório e o homem está livre de recidiva após três anos. HISTOPATOLOGIA: Ambos os tumores eram sólidos, com células arredondadas, lembrando oligodendroglia, positivas para sinaptofisina, cromogranina e NSE e algumas para GFAP, vimentina e proteína S-100. Microscopia eletrônica mostrou neurópilo entre os corpos celulares, mas sinapses eram raras.

Woman aged 24 years with fourth ventricular mass.

April 2005. A woman aged 24 years presented with symptoms related to a tumor in the fourth ventricle. Cytologically, the tumor was biphasic with areas typical of a classic ependymoma, including rosettes, and other areas containing grossly atypical giant cells. Many tumor cells were GFAP-positive and ultrastructural examination revealed microvilli and cilia. The histopathologic abnormalities place this tumor among the ependymomas. Its focal giant cell phenotype is very rare, but has been reported in 4 intracranial or filum ependymomas.

Central neurocytoma: report of two cases.

INTRODUCTION: Central neurocytomas are rare neuroectodermal tumors believed to arise from the subependymal matrix of the lateral ventricles. CASE REPORTS: A 26-year-old woman and a 33-year-old man each had a large, heterogeneous, contrast enhancing mass in the lateral ventricles at the foramen of Monro causing bilateral hydrocephalus. The woman died after surgery, but the man is asymptomatic after three years. HISTOPATHOLOGY: Both tumors were composed of isomorphic rounded cells positive for synaptophysin, chromogranin and NSE, while some reacted for GFAP, vimentin and S-100 protein. Electron microscopy revealed neuropil-like tissue between cells, but synapses were rare.

Intraventricular solitary fibrous tumor: an unusual tumor with radiological, ultrastructural, and immunohistochemical evaluation: case report.

OBJECTIVE AND IMPORTANCE: Intracranial solitary fibrous tumors have been described previously, but intraventricular solitary fibrous tumors are extremely rare. We present what is, to our knowledge, the first reported case of solitary fibrous tumor in the third ventricle. CLINICAL PRESENTATION: A 63-year-old man presented with weakness of his lower extremities and headaches. Computed tomography and magnetic resonance imaging of the brain revealed an enhancing mass in the posterior part of the third ventricle. INTERVENTION: The tumor originated from the wall of the left internal cerebral vein and extended to the posterior part of the third ventricle. Nearly total excision was performed via an infratentorial-supracerebellar approach. CONCLUSION: The differential diagnosis of intracranial solitary fibrous tumors includes fibroblastic meningioma, meningeal hemangiopericytoma, neurofibroma, and schwannoma. The differential diagnosis in the present case was greatly helped by the immunohistochemical and ultrastructural findings, along with a disease-free 3.5-year follow-up. These findings are presented with reference to previous reports.

Clinicopathological and ultrastructural study in two cases of chordoid glioma.

Chordoid glioma is a rare benign neoplasm of uncertain histogenesis occurring in the third ventricle/ /suprasellar region. Recently, data have emerged suggesting that chordoid glioma is a variant of ependymoma related to a specialised ependyma of the subcommisural organ or the lamina terminalis area. In this study, we report clinicopathological and ultrastructural findings in two chordoid glioma cases. In case 1, a tumour (1.5 cm in diameter) in a 62-year-old man invaded the anterior-basal part of the third ventricle in the lamina terminalis region. In case 2, a large tumour in a 51-year-old woman occupied the whole third ventricle. The tumour attached to the medio-basal hypothalamic region. Histologically, both cases revealed a distinct chordoma-like pattern and glial immunophenotype of tumour cells. Under the electron microscope the tumour cells exhibited microvilli, intercellular lumina, intermediate type junctions and focal basal lamina formations. These findings were similar to those previously reported in the chordoid glioma cases. Moreover, the intracytoplasmic cilia and subplasmalemmal pinocytic vesicles or caveoles were observed. The study supports the view of ependymal derivation of chordoid glioma. Its relation to lamina terminalis or infundibular/median eminence area presumably reflecting tumour origin from the modified ependyma of circumventricular organs of the third ventricle is discussed.

Central neurocytoma expressing characteristics of ependymal differentiation: electron microscopic findings of two cases.

We describe two cases of central neurocytoma in the lateral ventricle. Ultrastructural examination showed occasional cilia mixed in with sparse dense core vesicles and thin tumor cell processes containing parallel microtubules. These central neurocytomas revealed evidence of ependymal differentiation. We propose that central neurocytoma originates from multiple differentiation from the germinal matrix cell layer.

Fourth ventricle central neurocytoma: case report.

OBJECTIVE AND IMPORTANCE: Central neurocytomas (CNs) are typically located in the lateral ventricle. Primary origins in the fourth ventricle are very rare. We discuss the clinical symptoms, imaging findings, and microscopic features of these rare tumors. CLINICAL PRESENTATION: We report a case of a fourth ventricle CN in a 35-year-old male patient with the initial symptoms of progressive headaches and blurred vision for more than 2 months. Computed tomography and magnetic resonance imaging of the brain revealed a slightly enhanced tumor in the fourth ventricle, with obstructive hydrocephalus. INTERVENTION: Total surgical removal of the tumor was performed. The tumor was initially diagnosed as an oligodendroglioma. The final definitive diagnosis as a CN was made after special immunohistochemical studies. CONCLUSION: CNs located in the fourth ventricle are extremely rare. Immunohistochemical stains and transmission electron microscopy can provide useful diagnostic information. Total tumor excision is associated with favorable prognoses. Postoperative radiotherapy may be considered for cases of subtotal excision, anaplastic histological variants, or recurrent tumors.

Crush and imprint cytology of subependymoma: a case report.

BACKGROUND: There are few descriptions of the cytologic features of subependymoma because this neoplasm is rare and most commonly encountered incidentally at autopsy. Here we report a surgical case of subependymoma occurring in the lateral ventricle and provide the first documentation of the crush cytologic features of this tumor. CASE: A 34-year-old woman was found to have a tumorous lesion in the right lateral ventricle. At surgery, a 2-cm-diameter tumor was detected in the anterior horn. Histologic examination during surgery revealed that the mass was composed of loose,fibrillary networks and clusters of nuclei showing mild pleomorphism. A number of microcystic formations were evident. Histologically, the neoplasm was considered benign--specifically, a subependymoma. Papanicolaou- or Giemsa-stained crush specimens and imprint smears were also prepared. The cytologic morphology was fundamentally the same as the histologic. In the crush specimens, microcystic formations were readily visible. Moreover, details of the cellular morphology were more easily recognized in the cytologic slides than in the frozen sections. CONCLUSION: Cytologic examination, particularly crush cytology, appears to be useful for the rapid diagnosis of subependymoma during surgery in combination with the examination of frozen histologic sections.

Intraventricular neurocytoma with prominent myelin figures.

A case is reported of intraventricular neurocytoma that had characteristic light microscopic findings of neurocytoma with prominent intracytoplasmic concentric lamellar structures mimicking myelin sheaths. On routine H&E-stained sections, this tumor showed intracytoplasmic vesicular bleb-like structures having eosinophilic cores that were consistent with ultrastructural concentric lamellar structures. Immunohistochemically, this tumor was immunoreactive for synaptophysin and neurofilament, but negative for antibody to glial fibriallary acidic protein. Electron microscopic findings fulfilled the criteria for neurocytoma, with the presence of neurosecretory granules and neurotubules. These findings may suggest dual differentiation of this tumor into neurocytes and oligodendrocytes.

Mixed ependymoma-neuroendocrine tumor of the lateral ventricle.

A histologically unique glioneuronal neoplasm occupying the lateral ventricle of a child was immunohistochemically and ultrastructurally characterized. Its principal component exhibited the characteristic features of ependymoma, whereas a minor population of neuroendocrine cells, occurring singly and in small clusters, lay scattered throughout the ependymoma component. Yet another unusual finding was the presence of numerous elastic fibers within the extracellular matrix. This tumor is considered to represent a true mixed neoplasm consisting of ependymal and neuroendocrine elements.