1/17. Signet-ring cell ependymoma: case report with implications for pathogenesis and differential diagnosis.We describe light microscopic, immunohistochemical and ultrastructural features of a signet-ring cell ependymoma (WHO grade II) identified in a surgically resected left cerebellar cystic tumor from a 64-year-old man. Part of the tumor showed clear-cell differentiation. Immunohistochemical coexpression of glial fibrillary acidic protein and epithelial membrane antigen, characteristic of ependymoma, was detected in both components. Sinuous intermediate junctions, cytoplasmic lumina, and scant astroglial filaments were demonstrated by electron microscopy. Signet-ring cell change was shown to be induced by disproportionate cavitation of either microvillus-bearing cytoplasmic lumina or microrosettes. The staining qualities of clear cells were mainly due to paucity and degeneration of subcellular organelles. Therefore, signet-ring cell ependymomas represent a unique anomaly of intra- and extracellular compartmentalization to be distinguished from various unrelated forms of cytoplasmic volume increase, resulting in an optically similar "empty" appearance of tumor cells. As a clinically relevant consequence, signet-ring cell ependymoma must be included in the differential diagnosis of primary or metastatic neoplasms of the central nervous system, having in common a phenotype characterized by overdeveloped optically lucent cell bodies.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/17. ganglioglioma with a tanycytic ependymoma as the glial component.We studied a cystic ganglioglioma (GG) located in the right frontal lobe of the brain. Interestingly, the fibrillary spindle glial cells were often arranged in a fascicular pattern, and the generally uniform, round-to-oval delicate nuclei appeared to resemble those of ependymoma; and the neoplastic neurons often contained neurofibrillary tangles (NFTs). The glial component was positive for glial fibrillary acidic protein and occasionally contained granular or microvesicular structures positive for epithelial membrane antigen. Ultrastructural investigation revealed that the glial cells were ependymal in nature; intracytoplasmic lumina and intercellular microrosettes lined with cilia and microvilli, as well as long zonulae adherentes, were evident. In addition, chromogranin a-positive granular staining, neurosecretory-granule-like structures, and parallel arrays of microtubules were sometimes associated with the blood vessels. We considered the present case to be an unusual example of GG with an ependymoma, more precisely a tanycytic ependymoma, as the glial component; to our knowledge, the existence of ependymoma as the main glial component of this particular tumor has not been described before. The occurrence of NFTs, which has been reported in several cases of GG, was an additional, unusual feature.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
3/17. Case of clear cell ependymoma of medulla oblongata: clinicopathological and immunohistochemical study with literature review.Clear cell ependymoma has been included in the WHO classification of the central nervous system in 1993, after the first report by Kawano et al. Since then, only a few cases have been reported. Most clear cell ependymoma cases reported in the literature so far were located in the supra-tentorial compartment and/or cerebellum, and one case was in the cervical spinal cord. We report a case of clear cell ependymoma whose histological features were sufficient for the diagnosis and was unusually located in the fourth ventricle originating from the medulla oblongata. The tumor showed uniform tumor cells with perinuclear halo, nuclei being centrally located. Most of the tumor cells were arranged as perivascular pseudorosettes, and no ependymal canals or rosettes were evident. Mitotic figures were not frequent. Immunohistochemically, the tumor cells were strongly reactive for glial fibrillary acidic protein and vimentin, and weak and dot-like positive for epithelial membrane antigen. Clear cell change of the tumor cells appeared to be fixation artifact because this feature was not evident in the frozen section.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/17. Clear cell ependymoma with a lipidized component that developed in the thoracic spinal cord.The authors report a case of clear cell ependymoma with a lipidized component that developed in the thoracic spinal cord. A 59-year-old man was admitted to the hospital with an itchy pain in the left forearm to the left anterior and lateral chest for the past three years. Neurological findings on admission included dissociated sensory disturbance below the C8 level and increased deep tendon reflex in both lower extremities. An MRI scan of the spinal cord revealed an intramedullary tumor with a longer diameter of 3.5 cm at the T3-T4 level and a distended syrinx at the T2-T3 level. Surgery was performed after T1-T5 laminectomy. The gray, soft and well demarcated tumor was removed subtotally. light microscopy revealed a portion where clear cells proliferated and a portion where foamy cells proliferated. In some tissue, there were a very few nuclear areas suggestive of a perivascular pseudorosette. Neither nuclear division nor necrosis was observed. Immunohistochemically, the tumor cells were positive for glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), vimentin, and negative for cytokeratin, synaptophysin. The MIB-1 staining index was 0.25%. Based on these findings, diagnosis of clear cell ependymoma with a lipidized component was made.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
5/17. Highly anaplastic extraventricular ependymoma arising in an adult, mimicking metastatic adenocarcinoma with heavy stromal inflammation and emperiporesis.We report a case of extraventricular ependymoma arising in a 50-year-old woman that took an aggressive clinical course with recurrence three times. The initial tumor was a well-circumscribed nodule in the right temporal white matter measuring 2 cm in diameter. It showed variegated histological findings mimicking metastatic adenocarcinoma: an epithelioid arrangement of highly pleomorphic cells with pseudopapillary structures and perivascular pseudorosettes, and bizarre multinucleated giant cells with occasional emperiporesis surrounded by abundant mononuclear inflammatory cells, as well as a focal small area of conventional ependymoma. Emperiporesis and abundant mononuclear cell infiltration were not previously described in an ependymoma. The recurrent tumors predominantly showed an epithelioid pattern with frequent formation of astroblastoma-like pseudopapillary structures. Neoplastic cells were markedly atypical and had characteristic intracytoplasmic eosinophilic inclusion bodies. Much of the cells in both the initial and recurrent tumors showed a positive immunostaining for glial fibrillary acidic protein (GFAP) with accentuation to the cytoplasmic processes of the pseudorosettes and pseudopapillary structures. Epithelial membrane antigen (EMA) highlighted the epithelial differentiation of the tumor cells, while cytokeratin was completely negative. Although this tumor might be classified to at least WHO grade III from the histology and aggressive behavior, the exact grading is still controversial because of the rarity of such cases.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
6/17. Epithelioid ependymoma: a new variant of ependymoma: report of three cases.OBJECTIVE: To describe the pathological features of three very similar and unusual primary central nervous system tumors that are not readily recognized as conventional ependymomas but which, by ultrastructural examination, have an ependymomatous character. methods: Three distinctive tumors were found in a review of our files for cases of ependymoma. In each case, hematoxylin and eosin-stained sections were reviewed, and immunostains for epithelial membrane antigen, cytokeratin, vimentin, and glial fibrillary acidic protein were performed on formalin-fixed, paraffin-embedded sections. Electron microscopy was performed in each case. RESULTS: The tumors had a diffuse myxoid background, often containing tightly clustered cells that mimicked multinucleated giant cells, but lacking perivascular pseudorosettes or central lumen rosettes. glial fibrillary acidic protein and vimentin immunostains did not reveal perivascular processes. Epithelial membrane antigen immunostains showed a dot-like cytoplasmic immunoreactivity in some cell clusters in two of the three cases. Cytokeratin was negative in all three cases. However, ultrastructurally, the cells of each tumor had extensive surface microvilli; the giant cell-like clusters had cells with extensive close appositions, some junctions, and, in two cases, lumina with microvilli. Two of the patients were adults (both with temporal lobe tumors), and one patient was 13 years old and had a cervical spinal cord intramedullary tumor. Each tumor was sharply circumscribed from adjacent central nervous system tissue but was not encapsulated. One of the cases in an adult was mitotically highly active; this tumor recurred locally 4 years after initial gross total excision. CONCLUSION: These tumors are unusual variants of ependymoma. This pattern of ependymoma is sufficiently distinctive to be recognized in hematoxylin and eosin stains once the architecture of the epithelioid clusters is appreciated.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
7/17. Primary malignant ependymoma of the lung.In a 64-year-old woman, a solitary pulmonary nodule developed 30 months after combination chemotherapy and thoracic irradiation had been administered for small-cell carcinoma of the ipsilateral lung. No evidence of extrapulmonary tumor was identified, and the nodule was excised. The well-circumscribed tumor had histologic features of a malignant ependymoma. Immunohistochemical staining showed strong reactivity for glial fibrillary acidic protein; staining for S-100 protein, Leu-7, and vimentin was less intense. Focal reactivity for epithelial membrane antigen was also present. Stains for keratin, synaptophysin, and chromogranin were negative. Electron microscopy showed cohesive cells, the cytoplasm of which contained intermediate filaments. Rare well-formed junctions were also noted. flow cytometry of formalin-fixed paraffin-embedded tissue demonstrated dna aneuploidy. Six months after the ependymoma was diagnosed, the patient, who had a history of hypertension, died of an intracerebral hemorrhage.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
8/17. Large supratentorial ectopic ependymoma with massive calcification and cyst formation--case report.A 6-year-old boy presented with a large supratentorial ependymoma with massive calcification and central cyst formation manifesting as generalized convulsion and right hemiparesis. Computed tomography and magnetic resonance imaging showed a large, poorly enhanced, left frontal mass with massive calcification and a central cyst. angiography revealed no extracranial blood supply to the tumor, which was supplied by branches of the left middle cerebral artery. The patient underwent total resection of the tumor, which was located in the parenchyma with no dural attachment. The tumor was clearly demarcated and dissected subpially from the surrounding brain parenchyma. The surgical findings suggested no relationship with the lateral ventricular system. Histological examination of the tumor demonstrated perivascular pseudorosette formation and mitosis with massive calcification, and immunocytochemical reactivity for glial fibrillary acidic protein and epithelial membrane antigen, but not synaptophysin. These findings were compatible with ependymoma, world health organization grade 2. Postoperative magnetic resonance imaging clearly showed that the tumor was located in the intradural, intraaxial space with no relationship to the ventricles.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
9/17. Infratentorial giant cell ependymoma: a rare variant of ependymoma.We describe a giant cell ependymoma occurring in a 50-year-old man. The mass was located in the posterior aspect of the foramen magnum, extending from the cerebellar tonsil to the upper cervical spine. The tumor was a highly cellular neoplasm showing biphasic histology. Diffuse sheets of non-cohesive atypical giant cells, having eccentrically located single or multiple nuclei and plump eosinophilic cytoplasm, partly infiltrated the desmoplastic inflammatory stroma. Parts of perivascular pseudorosette-forming or pseudopapillary areas were composed of atypically elongated cells, which looked like conventional anaplastic ependymoma. There was a transitional area between two patterns. Numerous mitoses and focal necrosis were observed. Immunohistochemically, the tumor cells were immunoreactive for glial fibrillary acidic protein, vimentin, S-100 protein, and CD99. None of the tumor cells showed immunoreactivity for epithelial membrane antigen except for the intracytoplasmic lumen of a few vacuolated cells. Ultrastructurally, tumor cells were ependymal in nature; we noted cytoplasmic intermediate filaments and intercellular microrosettes with microvilli, cilia, and long zonula adherens. The features of this tumor, e.g. its superficial location, mixed giant cells, perivascular pseudorosettes or papillaries, complicated its differentiation from rhabdoid/papillary meningioma. However, immunohistochemistry and electron microscopy confirmed the diagnosis of ependymoma. The giant cell variant should be included in the subclassification of the ependymoma.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
10/17. November 2004: intradural mass of the cauda equina in a woman in her early 60s.November 2004. A 63-year-old woman presented with slowly aggravating lower back pain and recent urinary urge incontinence. MRI revealed a sharply-delineated, partly cystic intradural mass with inhomogenous contrast-enhancement and ectatic vessels at the upper pole. An ependymoma was suspected, and the tumor was resected in toto. Histologically, at first glance, the tumor strongly resembled an ependymoma, showing a monomorphic cellular pattern, perivascular pseudorosettes and ependymal canal-like structures. However, the finding of a delicate collagen capsule, compartmentation of tumor cells into zellballen and the presence of ganglionic cells were untypical. These features were indicative of a paraganglioma with a gangliocytic component. Immunoreactivity of the tumor cells for neuroendocrine antigens, the detection of GFAP-positive sustentacular cells and the ultrastructural confirmation of neurosecretory granules substantiated this diagnosis. The clinical, radiological and morphological similarity between ependymomas, which are far more common in the cauda equina region than paragangliomas, has led to substantial diagnostic confusion in the past.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
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