Cauda equina tumor with ependymal and paraganglionic differentiation.

We describe the case of a 31-year-old woman who was first treated for a pigmented choroid plexus papilloma of the fourth ventricle. Ten year later, she developed a new tumor in the region of the cauda equina. This second neoplasm contained areas of papillary ependymoma that displayed phosphotungstic acid hematoxylin-positive glial fibers and immunoreactivity for glial fibrillary acidic and S-100 proteins. Areas of ependymoma merged with others that displayed the appearance of a paraganglioma, including lobules and nests of chief cells immunoreactive for neuron-specific enolase, synaptophysin, chromogranin, and serotonin. Satellite cells, but not chief cells, stained for glial fibrillary acidic and S-100 proteins. Electron microscopy showed features of both ependymal and paraganglionic differentiation, including intercellular lumina with microvilli, junctional complexes, cell processes with closely packed filaments, and dense core granules. Our case represents a rare example of a cauda equina neoplasm with simultaneous ependymal and paraganglionic differentiation. To our knowledge, this is the first described example of a tumor of this region showing features of both ependymoma and paraganglioma.     

Clear-cell Ependymoma of the Cerebellum: A Case Report

A case of clear-cell ependymoma occurring in the cerebellum of a 3-year-old girl is reported. Light-microscopically, the tumor consisted mainly of clear cells with a perinuclear halo and showed some vague perivascular pseudorosettes, not true rosettes. In addition, the histological features of anaplasia, characterized by increased mitosis and focal pseudopalisading necrosis, were also observed. Immunohistochemically, the tumor cells were focally positive for glial fibrillary acidic protein and weakly positive for epithelial membrane antigen. Ultrastructurally, the intermediate junctions and rudimentary cilia confirmed the ependymal differentiation. Fifteen cases of infratentorial clear-cell ependymoma have been reported to date, and this case is the second childhood tumor among them, to the best of the authors' knowledge.     

Clear-cell ependymoma of the cerebellum: a case report

A case of clear-cell ependymoma occurring in the cerebellum of a 3-year-old girl is reported. Light-microscopically, the tumor consisted mainly of clear cells with a perinuclear halo and showed some vague perivascular pseudorosettes, not true rosettes. In addition, the histological features of anaplasia, characterized by increased mitosis and focal pseudopalisading necrosis, were also observed. Immunohistochemically, the tumor cells were focally positive for glial fibrillary acidic protein and weakly positive for epithelial membrane antigen. Ultrastructurally, the intermediate junctions and rudimentary cilia confirmed the ependymal differentiation. Fifteen cases of infratentorial clear-cell ependymoma have been reported to date, and this case is the second childhood tumor among them, to the best of the authors' knowledge.     

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.     

An immunohistological study of 66 ependymomas

Sixty-six ependymomas were examined immunohistologically to determine their distribution of glial fibrillary acidic proteins, S-100 protein and vimentin. The neoplasms were subdivided into four groups: (1) ependymomas from the cauda equina, predominantly of the myxopapillary type; (2) benign ependymomas; (3) malignant ependymomas; and (4) ependymoblastomas. Marked differences in antigen reactivity were observed between each group. The intensity of the reaction with the three antibodies was strongest in malignant ependymomas. Ependymomas from the cauda equina showed a patchy distribution of positivity for the three antigens in cells surrounding blood vessels but there was no staining of collagenous septa or the myxoid areas. In ependymoblastomas, the cells of the rosettes were negative for glial fibrillary acidic protein, but there was focal positivity for vimentin and S-100. Other areas showed tumour cells containing moderate amounts of vimentin and small amounts of S-100, and a few bands of filaments positive for glial fibrillary acidic protein. The cytogenetic and biological implications of these findings are discussed.     

Primary extraneural myxopapillary ependymoma of the broad ligament

Primary extraneural ependymomas are rare tumors that arise in ectopic sites, including pulmonary, sacrococcygeal region, ovarian, and paraovarian tissues. Four such ependymomas reported in the literature involve the paraovarian tissues, including 2 broad ligament ependymomas. Here we describe a myxopapillary ependymoma of the broad ligament in a 22-year-old woman, which may be the first tumor of this type to be reported in this location. Cytology, histology, cytochemistry, immunohistochemistry, and flow cytometry ploidy analysis are studied and described. Identification of perivascular ependymal rosettes, ependymal canals, vimentin and glial fibrillary acidic protein immunoreactivity, cytochemical staining of blepharoplasts or terminal bars by phosphotungstic acid hematoxylin, and presence of multiple foci of myxoid degeneration among the ependymal rosettes characterized a myxopapillary ependymoma.     

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.     

伸展细胞型室管膜瘤的临床病理特点

目的：观察一少见的特殊类型室管膜瘤的临床病理特点,拟译名为伸展细胞型室管膜瘤。方法：复习3例此型的临床病理和免疫组化资料及有关文献。结果：3例肿瘤均位于脊髓内。它们的临床表现和放射影像学与室管膜瘤其他类型表现相同,病理形态学上,瘤细胞呈现双极的长梭形胶质细胞,形成不典型的血管周菊形团,GFAP、EMA弱阳性,而vimentin强阳性,而可与星形细胞瘤及神经鞘瘤相鉴别,其预后与其他类型室管膜瘤相类似。结论：由于肿瘤由双极、长梭形细胞组成。及tanycyte来源于tanyos有stretch伸出展开之意,“tanycytic ependymona ”以译成“伸展细胞型室管膜瘤”为妥。     

Ectopic cervical anaplastic ependymoma

Ependymomas generally arise in the central nervous system (CNS), although rare primary extraneural ependymomas have been observed. Reported herein for the first time is the case of a patient with primary ectopic cervical anaplastic ependymoma. The tumor was found in the right neck root region of a 35-year-old man. No additional tumor was found in the CNS or in other parts of the body. The patient received surgery and post-surgical local radiotherapy. Microscopically, the tumor consisted of round to oval cells with fine chromatin, distinct nucleoli, moderate nuclear atypia and numerous mitoses (>25/10 high-power fields) in a densely cellular growth pattern with characteristic fibrillary cytoplasm and formation of perivascular pseudorosettes. By immunohistochemistry, the tumor cells were positive for glial fibrillary acidic protein, epithelial membrane antigen (EMA), vimentin and S-100 protein. EMA staining showed a membranous as well as a paranuclear pattern of immunoreactivity. Electron microscopic studies revealed that tumor cells form micro rosettes, into which microvilli and cilia projected. The diagnosis was World Health Organization grade III anaplastic ependymoma. There is no evidence of local tumor recurrence or distant metastasis after 30 months follow up. The present case adds yet another unique example to the already diverse spectrum of head and neck neoplasms encountered in surgical pathology.     

Ovarian and omental ependymomas in peritoneal washings: cytologic and immunocytochemical features

The cytologic findings in peritoneal washings of two women, one of whom had an ovarian ependymoma and the other a primary omental ependymoma, are reported. The ependymomas were characterized by the presence of numerous, isolated, spindle and stellate cells as well as groups of cells forming true rosettes. The tumor cells displayed slightly pleomorphic, round-to-oval eccentric nuclei and abundant fibrillary cytoplasm with tapering cytoplasmic processes. In addition, one of the patients had numerous papillae and cell clusters with associated psammoma bodies indistinguishable from those found in low-grade serous carcinoma. The demonstration of glial fibrillary acidic protein (GFAP) in both cases by immunocytochemical procedures indicates the usefulness of this method in cytologic preparations to confirm the diagnosis of these uncommon neoplasms.     

Primitive neuroectodermal tumor of the testis. Report of a case

A 30-year-old man died of a testicular tumor with widespread metastases. Both the right testis and the adjoining epididymis were replaced by a mass that consisted mainly of small cells, but differentiated focally into medullary tubules, ependymal rosettes, and glia in which glial fibrillary acidic protein was demonstrated; rare foci of cartilage and cellular mesenchyme established the teratomatous nature of the neoplasm. We believe this is the first reported case of a primitive neuroectodermal tumor of the testis.     

Extraspinal ependymoma of the broad ligament

Extraspinal ependymoma is a rare tumor, occurring most commonly in the sacrococcygeal region, and only a small number of cases have been reported to arise in the uterine ligament. Herein is reported a case of extraspinal ependymoma arising in the broad ligament of a 27‐year‐old woman. The lesion was 14 cm in diameter with an intra‐abdominal implant in the omentum. On cut section the tumor was found to be solid, and demonstrated hemorrhaging, necrosis, myxoid foci, and central cystic spaces. Microscopically the tumor was composed of a proliferation of short spindle or polygonal cells arranged in short fascicles or in a solid sheet‐like fashion with occasional perivascular pseudorosettes, together with myxoid areas and variable histological architectures exhibiting cribriform, pseudopapillary, and variable‐sized cystic patterns. On immunohistochemistry most tumor cells were positively reactive to glial fibrillary acidic protein (GFAP), CD99, estrogen receptor, and progesterone receptor. The patient has remained disease‐free for 6 months after the adjuvant chemoradiotherapy. Extraspinal ependymoma should be considered as a differential diagnosis when examining unusual intrapelvic tumors, especially in young female patients. The identification of characteristic histological features such as perivascular pseudorosettes and immunohistochemical expression of GFAP are helpful for confirming the diagnosis.     

Cytologic differential diagnosis of myxoid and mucinous neoplasms of the sacrum and parasacral soft tissues

A diagnostically important group of lesions involving the sacrum, spinal canal, and parasacral soft tissues is characterized by a myxoid or mucinous background in cytologic smears. This group of myxoid/mucoid neoplasms includes chordoma, myxopapillary ependymoma, metastatic mucinous adenocarcinoma, and extraskeletal myxoid chondrosarcoma. Despite the similarity of the background substance, each neoplasm within this differential diagnosis has a characteristic composite set of morphologic and immunophenotypic features. Because many of these masses are not easily surgically biopsied, fine-needle aspiration (FNA) is often used for their diagnosis. The private consultation records of the author and the cytology files of the University of Utah Department of Pathology were searched for all lesions arising in or around the sacrum. These cases were reviewed to determine which had a myxoid/mucinous background. Fourteen neoplasms were found and comprise the study set. Four of these cases had cell block material in addition to Diff-Quik-stained smears; a panel of antibodies, including cytokeratin, glial fibrillary acid protein (GFAP), S-100 protein, and carcinoembryonic antigen (CEA), was performed on the cell block material. The smears were evaluated for cytologic features, including the presence of rosette-like structures, physaliphorous cells, gland-like structures, chondroid fragments, "signet ring" and "goblet" cells, as well as the character of the myxoid/mucinous background substance.The cases included one myxopapillary ependymoma, 10 chordomas, two mucinous adenocarcinomas of colonic or gastric origin, and one myxoid chondrosarcoma. Physaliphorous cells were found to be highly specific for chordoma, while a fibrillary myxoid stroma containing cells with elongated cytoplasmic processes and cells lying in a rosette-like pattern around central cores of myxoid to fibrillary stroma were highly characteristic of myxopapillary ependymoma. Fragments of a myxoid/chondroid matrix with lacunar-like spaces strongly supported the diagnosis of myxoid chondrosarcoma. "goblet" or "signet ring" cells with a single distinct vacuole favored mucinous adenocarcinoma. There appear to be sufficient cytomorphologic features present within the FNA smears and cell block material to allow cytologic separation of the more common myxoid and mucinous neoplasms involving the sacral and parasacral tissues.     

Ependymoblastoma: a histological, immunohistological and ultrastructural study of five cases

Five ependymoblastomas were studied by means of routine histological techniques, immunohistology and electron microscopy. The tumours were characterized histologically by medium sized, poorly differentiated cells with round or oval nuclei frequently in mitosis and by ependymoblastic rosettes. Reactions for cytokeratin and neurofilament were negative and tubular material positive for glial fibrillary acidic protein was scanty. All five tumors demonstrated positivity for vimentin and S-100 protein. Electron microscopy showed poorly differentiated cells with high nucleo-cytoplasmic ratio and scanty cytoplasmic organelles. Sparse rosettes were present and the cells were united by junctional complexes. Frequent rudimentary or incomplete cilia, a few basal bodies and a few short intercellular glial-like filaments were seen. Features differentiating ependymomas and anaplastic ependymomas from ependymoblastomas are discussed and the need for a definite category separating ependymoblastomas from the former tumours is emphasized.     

Ependymoma: Ultrastructural Studies of Two Cases

Several unusual ultrastructural findings in two ependymomas are reported. In case 1, a grade I ependymoma of the fourth ventricle, there were rosettes, perivascular pseudorosettes, and tumor cells having unusual intracytoplasmic vacuoles by light microscopy. Ultrastructurally, these vacuoles were frequently microrosettes as well as scattered, degenerated cytoplasmic processes of tumor cells. The lumina of some of the microrosettes were bordered by abnormally long and malformed zonulae adherentiae. In case 2, a recurrent grade III ependymoma of the third ventricle, there were rosettes and perivascular pseudorosettes as well as more cellular and anaplastic areas by light microscopy. Ultrastructurally, the cytoplasmic processes of tumor cells in perivascular pseudorosettes contained frequent dense-core vesicles and occasional parallel arrays of microtubules. These structures do not occur in normal mammalian ependymal cells but do occur in the ependymal tanycyte, a related cell that is plentiful in the walls of the third ventricle. Thus some of the tumor cells of this third ventricle ependymoma appear to have differentiated as tany-cytes.     

Ovarian ependymoma

A 76-year-old woman presented with a large calcifying mass behind the bladder. The tumor contained solid areas of a yellowish white color. Microscopic examination revealed highly cellular solid areas with many typical ependymal perivascular pseudorosettes. The cells contained uniform round-to-oval nuclei, some of which had irregular contours, clumped chromatin and occasional prominent nucleoli. There was widespread geographic necrosis and there were 5 atypical mitotic figures per 10 high power fields. Glial fibrillary acidic protein (GFAP) immunopositivity was observed in the cytoplasm of the tumor cells. Based on the histopathologic and immunohistochemical features, the tumor was diagnosed as an anaplastic ependymoma. This is to the best of our knowledge only the second case of anaplastic ependymoma in the medical literature.     

Ependymoma: Ultrastructural Studies of Two Cases

Several unusual ultrastructural findings in two ependymomas are reported. In case 1, a grade I ependymoma of the fourth ventricle, there were rosettes, perivascular pseudorosettes, and tumor cells having unusual intracytoplasmic vacuoles by light microscopy. Ultrastructurally, these vacuoles were frequently microrosettes as well as scattered, degenerated cytoplasmic processes of tumor cells. The lumina of some of the microrosettes were bordered by abnormally long and malformed zonulae adherentiae. In case 2, a recurrent grade III ependymoma of the third ventricle, there were rosettes and perivascular pseudorosettes as well as more cellular and anaplastic areas by light microscopy. Ultrastructurally, the cytoplasmic processes of tumor cells in perivascular pseudorosettes contained frequent dense-core vesicles and occasional parallel arrays of microtubules. These structures do not occur in normal mammalian ependymal cells but do occur in the ependymal tanycyte, a related cell that is plentiful in the walls of the third ventricle. Thus some of the tumor cells of this third ventricle ependymoma appear to have differentiated as tany-cytes.     

伸展细胞型室管膜瘤的病理学观察

目的 探讨伸展细胞型室管膜瘤的临床病理特点、诊断及鉴别诊断。方法 对6例伸展细胞型室管膜瘤进行光镜、免疫组化、特殊染色、电镜观察并结合文献进行分析。结果 肿瘤主要由长梭形细胞构成,呈束状交错状、车辐状排列,可见围绕血管分布,形成假菊形团。瘤细胞呈单极或双极突起细长,分化好,核分裂象罕见,未见坏死。免疫组化标记瘤细胞vimentin强阳性,GFAP、S-100蛋白、EMA阳性,Syn和HHF35阴性。超微结构观察见较多的中间细丝和发育好的的桥粒,以及细胞间腔隙内有微绒毛。结论 伸展细胞型室管膜瘤起源于脑室附近伸展细胞,是罕见的室管膜瘤的一个亚型,在诊断上往往易与其它梭形细胞为主的神经上皮肿瘤相混,病理诊断依赖于组织学、免疫组化、特殊染色和电镜观察。免疫组化和特殊染色在鉴别诊断中有重要价值。     

Histological characterization of an ependymoma in the fourth ventricle of a cat

A tumour occupying the fourth ventricle in a 3-year-old cat was removed surgically and characterized as a tanycytic ependymoma on the basis of histological features of low cellularity, inconspicuous perivascular pseudorosettes and fascicular architecture. Immunohistochemical analysis of sections revealed that the neoplastic cells were immunoreactive for glial fibrillary acidic protein (GFAP), vimentin and S-100. The histological and immunohistochemical findings were similar to those of human tanycytic ependymoma, a subclassification of ependymoma not previously described in domestic species.     

Fine-needle aspiration of metastatic sacrococcygeal myxopapillary ependymoma

A 45-yr-old white woman with a 24-yr history of sacrococcygeal myxopapillary ependymoma developed a large metastasis of scalp and skull diagnosed as metastatic ependymoma on fine-needle aspiration, based on cytologic features, histologic pattern in cell block fragments, and a positive reaction with the glial fibrillary acidic protein immunoperoxidase study. The fine-needle study obviated the need for biopsy in this case, for which a surgical approach was considered to be inappropriate due to the extent of the process demonstrated by various imaging techniques.