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.

Intramedullary clear cell ependymoma in the thoracic spinal cord: a case with its crush smear and ultrastructural findings

Clear cell ependymoma was included in the World Health Organization classification of the nervous system in 1993, and all the reported cases, except for two in the spinal cord, were located in the brain, mainly in the supratentorial compartment. Astrocytomas outnumber ependymomas in the spinal cord, and the two entities partly share cytologic findings such as long, bipolar glial processes and oval to round nuclei resembling those seen in pilocytic astrocytoma. Here, we report the first Korean case of intramedullary clear cell ependymoma of the spinal cord, which is the third case situated in the spinal cord in the literature. The crush smear revealed round-to-oval nuclei with occasional nuclear eosinophilic inclusion and rare nuclear grooves. Cytoplasm had fluffy eosinophilic glial processes, and acellular fibrillary zone. On hematoxylin-eosin stain, oval to round tumor cells had large central nuclei with indistinct nucleoli and a moderate amount of clear cytoplasm, i.e. perinuclear halo, mimicking oligodendroglioma. Perivascular pseudorosettes and ependymal clefts were rarely found. In retrospect, perinuclear halo was absent on crush smears. Ultrastructurally, they had extensive surface microvilli and edematous cytoplasm filled with abundant glial filaments and microlumens with or without microvilli. Intercellular long cell junctions of the zipper-like zonula adherens type were found.

Oncocytoma of the spinal cord causing paraplegia – a case report

STUDY DESIGN

Case report.

OBJECTIVES

To describe a rare case of oncocytoma arising from the spinal cord in a 40-year old woman.

SETTING

Republic of Korea.

METHODS

The patient's history, physical examination, radiological and pathological findings were reviewed.

RESULTS

A 40-year-old woman presented with 3-month history of low back pain. Magnetic resonance imaging revealed an intradural extramedullary mass located between L1 and L4. She refused any surgical treatment and so was discharged. At 10 days after discharge, an emergency operation was performed because of sudden paralysis in both lower extremities. The confirmed diagnosis is oncocytoma. At 4 months after surgery, the patient failed to obtain neurological recovery from complete paraplegia.

CONCLUSIONS

Since the progression of an intradural extramedullary mass that shows minor neurological symptoms can lead to complete paraplegia in a short time, close observation and early surgical decompression are necessary.

Spinal adrenal cortical adenoma with oncocytic features: report of the first intramedullary case and review of the literature

Ectopic adrenal cortical neoplasms are extremely rare, and only a few have involved the CNS. We report the first case of an intramedullary oncocytic adrenal cortical neoplasm of the spinal cord with immunohistochemical (IMHC) confirmation. A 27-year-old man presented with progressive lower extremity weakness, spastic paraparesis, decreased reflexes, and hypoesthesia below T10. A spinal myelogram showed cauda equina blockade and obliteration of sacral nerve roots. This prompted emergent surgical intervention. A well-circumscribed, approximately 3 x 2 cm, light brown to tan, intramedullary tumor was identified at the level of the conus medullaris. Histologically, the tumor showed sheets and nests of plump, cytologically bland polygonal cells with abundant eosinophilic cytoplasm. A single mitosis, but no necrosis, was identified. By IMHC, the cells were positive for inhibin, melan-A, and synaptophysin, and negative for GFAP, EMA, cytokeratins, S-100, HMB-45, and chromogranin. Electron microscopy study performed from paraffin-embedded tissues demonstrated abundant mitochondria, and lipid vacuoles. This case confirms the occurrence of adrenal cortical neoplasms in the CNS and is the first report of an intradural, intramedullary adrenal cortical adenoma of the spinal cord, and the first to occur in a male. This tumor should be considered in the differential diagnosis of tumors of the CNS.

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.

Imprint cytologic features of intracytoplasmic lumina in ependymoma. A report of two cases

BACKGROUND

Intracytoplasmic lumina have been recently recognized as a characteristic histologic feature of ependymoma. However, the cytologic diagnostic usefulness has not been discussed. We encountered two imprint cytology cases of spinal cord ependymomas in which there were intracytoplasmic lumina in the tumor cells.

CASES

Two women had spinal cord tumors on magnetic resonance imaging. Imprint cytology study was carried out on the resected tumors. The cytologic specimen of the first case, aged 52, showed tumor clusters consisting of elongated epithelioid cells, a few of which also had intracytoplasmic lumina. Histologically, tumor cells formed ependymal rosettes and pseudoperivascular rosettes. There were a few tumor cells with intracytoplasmic lumina. The cytologic specimen of the second patient, aged 37, had scattered and isolated tumor cells with intracytoplasmic lumina resembling signet-ring cells and paired tumor cells forming small, glandlike structures. Histologically, the tumor was composed mainly of signet-ring-like cells containing intracytoplasmic lumina.

CONCLUSION

Intracytoplasmic lumina were observed in the imprint cytologic specimens of spinal cord ependymoma. The diagnosis of ependymomas can be made cytologically when intracytoplasmic lumina are found since no other primary neuroepithelial tumors of the central nervous system possess such a characteristic feature.

Spinal tanycytic ependymomas

Three cases of spinal tanycytic ependymoma are reported, a man aged 45 years and two women aged 36 and 55 years. Each patient developed gradual paraparesis over a few months prior to admission. Magnetic resonance imaging showed an enhancing, well-circumscribed tumor in the spinal cord in each case. Histologically, the tumors consisted of monotonous proliferation of long spindle cells with markedly eosinophilic cell processes; focally forming perivascular pseudorosettes. The tumor cells were strongly immunopositive for glial fibrillary acidic protein, S-100 protein and vimentin. Ultrastructurally, in addition to massive intermediate filaments, many tumor cells showed abundant microtubules. Well-developed desmosomes and microvilli/cilia-lined microlumina were occasionally observed. The tumors were grossly totally removed and the patients remain recurrence free at 9, 9, and 2 years postoperatively. Reviewing reported cases including our three cases, tanycytic ependymoma may occur frequently in spinal cord, especially in the cervical region of the spinal cord. Since histologically it resembles pilocytic astrocytoma and schwannoma, tanycytic ependymoma should be included in the differential diagnosis of benign spindle cell tumors of the central nervous system.

Pigmented schwannoma of the ventral spinal cord

Pigmented schwannomas of the spinal canal are rare entities. We present a case of such in an unusual, ventral intradural, extramedullary location in a 27-year-old man. Imaging and histopathologic findings, including electron microscopy, showed an intradural, extramedullary pigmented schwannoma, densely adherent to the leptomeninges of the anterior median septum. This lesion is demonstrative of the neuroectodermal origin of these lesions and represents a rare location of these tumors.

Solitary fibrous tumor of the spinal cord. Report of a case with scrape cytology

BACKGROUND

Solitary fibrous tumor is a rare spindle cell tumor and has been forced at a variety of sites. To the best of our knowledge, only two cases of solitary fibrous tumor arising in the spinal cord have been reported; no cytologic findings were documented.

CASE

A 62-year-old male presented with a spinal cord tumor. A scrape smear of the resected tumor revealed naked, spindle-shaped nuclei. Some nuclei were twisted or had long spindles. In the background, abundant, thin and thick collagen fibers were present. Immunohistochemically, the spindle cells were positive for CD34 and negative for S-100 protein and alpha-smooth muscle actin. Histologic diagnosis of the tumor was benign solitary fibrous tumor.

CONCLUSION

Our case indicates that solitary fibrous tumor can occur in the spinal cord and should be differentiated from other benign spindle cell tumors, such as meningioma and schwannoma. The key cytologic features of solitary fibrous tumor may be the presence of abundant thin and thick collagen fibers in scrape specimens.

Lipidized (foamy) tumor cells in a spinal cord ependymoma with collagenous metaplasia

We report a 49-year-old woman with a spinal cord ependymoma located in the thoracolumbar region. At surgery, a soft dark-grayish tumor, which contained a hard whitish area, was removed. The specimen was a moderately cellular tumor with a central core made up of collagen nodules poor in cellular elements. Many of the tumor cells possessed ground glass-like eosinophilic cytoplasm, and frequently foamy tumor cells were evident. Perivascular pseudorosettes, ependymal rosettes and canals were present, the latter being rare. Many tumor cells, including those with foamy cytoplasm, were positive for glial fibrillary acidic protein. Similar tumor cells were also seen among, and even within, the collagen nodules. The MIB-1 labeling index was 0.66%. Ultrastructurally, the frequent lipidized tumor cells were ependymal in nature; cytoplasmic 10-nm-wide filaments, and intracytoplasmic lumina and intercellular microrosettes lined by microvilli were evident. Cilia were very rare. We considered the present case to be an unusual, lipidized variant of ependymoma. The collagen nodules appeared to be produced by the tumor cells themselves.

Nuclear grooves in ependymoma. Cytologic study of 21 cases

OBJECTIVE

To study the efficacy of crush preparation smears in the diagnosis of ependymomas.

STUDY DESIGN

The study group consisted of 21 patients aged 7-61 years. All were admitted to Shiraz University hospitals (Nemazi and Beheshti) with intramedullary tumors. Fourteen were ventricular (fourth ventricle), 1 was in the parietal lobe, 5 were in the lumbosacral region and 1 was in the cauda equina. Intraoperative crush preparation smears were obtained from tissue, which was sent for frozen section and diagnosed cytologically. The control group consisted of 123 intracranial tumors (meningiomas, schwannomas, astrocytomas, oligodendrogliomas, medulloblastomas, pituitary adenomas, choroid plexus papilloma, craniopharyngioma and metastatic tumors).

RESULTS

The smears in 11 cases revealed perivascular pseudorosettes, and the smears in 21 cases revealed ependymal rosettes. Papillary clusters, calcification and intranuclear inclusions were seen in two cases. Acinar structures were seen in seven cases. Myxomatous material was seen in one case. Nuclear grooves were seen in 15 cases. All cases were diagnosed as ependymomas. Biopsy specimens confirmed the cytologic diagnosis. The tumors in the control group showed no evidence of nuclear grooves.

CONCLUSION

Fifteen cases of ependymoma showed a substantial number of nuclear grooves. Intraoperative crush preparation smears were very useful in the diagnosis of ependymomas and helped with the rapid interpretation of frozen sections.

Solitary fibrous tumor of the spinal cord

We report a case of primary solitary fibrous tumor occurring in the intramedullary thoracic spinal cord in a 47-year-old man. The tumor predominately consisted of spindle cells separated by abundant collagen; a few areas of hemangiopericytomatous morphology were also present. The diagnosis was confirmed by immunohistochemistry and electron microscopy. The tumor was reactive to vimentin and CD34 but was negative for glial fibrillary acid protein (GFAP), S-100, smooth muscle actin, epithelial membrane antigen, HMB-45, myelin basic protein, and keratin; ultrastructural examination showed fairly undifferentiated cells within a collagenous matrix, few tight junctions, and sparse extravascular basement membrane. The occurrence of this tumor within the spinal cord parenchyma and in other extraserosal sites emphasizes the current belief that solitary fibrous tumors arise from mesenchymal tissues and are not restricted to the pleura and other serosal surfaces. Furthermore, solitary fibrous tumor is an entity that must be considered in the differential diagnosis of spindle cell central nervous system neoplasms.

Myxopapillary ependymomas: a clinicopathologic study of 14 cases including MIB-1 and p53 immunoreactivity

Few studies have examined cell proliferation or p53 immunoreactivity in myxopapillary ependymomas. This study retrospectively examines tumor MIB-1 and p53 immunohistochemical features in 14 patients (eight women, six men; age range, 12-69 yr; median, 32 yr) with myxopapillary ependymoma. Their preoperative symptoms lasted from 2 months to 18 years (median, 12 mo) and most commonly involved lower back pain. The tumor was in the lumbar spinal cord region in 12 patients, the sacral cord in 1, and both the lower thoracic and upper lumbar cord in 1. In three patients, cerebrospinal fluid protein levels were markedly elevated, with negative cytologic results. Thirteen patients underwent a gross total resection. All of the tumors demonstrated histologic features diagnostic of myxopapillary ependymoma. Four cases had focal, prominent, nuclear pleomorphism. From 1 to 5 mitotic figures per 10 high power fields were identified in four tumors. There was no vascular proliferation or necrosis. Nine patients are alive at last known follow-up with no evidence of tumor (median, 36 mo); four are alive with residual tumor (median, 40 mo); and one died after 74 months (tumor status unknown). Eleven patients received adjuvant radiation and/or chemotherapy. Six experienced at least one tumor recurrence at intervals of 20 to 132 months. MIB-1 indices on the initial tumor resection ranged from 0 to 5.5 (median, 0.9) in 12 cases. In three patients with recurrent tumor, MIB-1 indices were higher in the initial tumor in two cases and lower in one. p53 Immunostaining of 13 tumors showed rare positive-staining tumor cell nuclei. The conclusions are that myxopapillary ependymomas grow slowly; that MIB-1 labeling indices are unreliable predictors of tumor recurrence; and that the lack of p53 immunostaining in most myxopapillary ependymomas in this series suggests that this gene might not play a significant role in the pathogenesis of these tumors.

Tanycytic ependymoma

Tanycytic ependymoma is an uncommon fibrillar variant of ependymoma characterized by streams of piloid, or hair-like, cells having "ependymal" nuclei. True ependymal rosettes are absent, and perivascular rosettes are inconspicuous. Misinterpretation as schwannoma or astrocytoma is a diagnostic problem and well-documented cases are scarce. The purpose of this report is to document the ependymal features of the neoplasm and to increase awareness of the entity's existence. Biopsy tissues from three patients with tanycytic ependymoma were examined. All tumors consisted of sheets of spindle cells that were positive for glial fibrillary acidic and S-100 proteins. Ultrastructural examination showed characteristic ependymal features, including intracytoplasmic intermediate filaments, prominent intercellular junctions, numerous slender surface microvilli, and microvilli-lined lumina. Accurate recognition of the ependymal nature of this spindle neoplasm requires a high index of suspicion. Because the spindle cells are immunoreactive with antibodies to both glial fibrillary acidic and S-100 proteins, ultrastructural confirmation of ependymal features is necessary.

Clear cell meningioma: report of a spinal case

A sacrococcygeal case of clear cell meningioma in a 38-year-old man is reported. Compared to the seven spinal clear cell meningiomas described so far, this case demonstrated the highest recurrency rate. Multiple recurrences were most likely due to the extensive infiltrative growth pattern of the tumor hindering complete microscopic surgical resection. Histologic parameters were not relevant to predict recurrences, since cellular anaplasia was lacking and growth fraction was low in the first operation and all subsequent recurrences. In view of what is now known of clear cell meningiomas, the tumor showed all histologic and immunohistochemical features which are typical for this tumor entity. However, the tumor was first diagnosed by capable pathologists and neuropathologists as fibroma-like mesenchymal tumor, metastatic renal carcinoma, chordoma, chondroma untypical osteosarcoma, and microcystic meningioma. Correct diagnosis was made by electron microscopy which has revealed comparable findings to those of other rare electron microscopical cases reported so far; high content of cytoplasmic glycogen diffusely distributed throughout the cytoplasm or aggregated within vacuoles, intermediate filaments, desmosomes, interdigitation of cell membranes and large amounts of collagen fibers, some of which were of the giant amianthoid type. Since meningiomatous features of clear cell meningiomas are not obvious light microscopically and the tumors may be confused with nonmeningiomatous neoplasms, electron microscopical investigation is highly recommended in each case of suspected clear cell meningioma.

Subependymoma of the cervical cord

Subependymomas are benign lesions of the central nervous system. Their occurrence in the spinal cord is rare. It is important to recognize these lesions because their total surgical excision is feasible and leads to long term symptom remission-a case of a spinal subependymomas localized in the cervical region is discussed and a review of the relevant literature is presented.

Multiple neuroepithelial tumors of different cell types--case report

A 31-year-old male developed intramedullary tumors in the medulla oblongata and the upper cervical spinal cord. He was first admitted with tetraparesis. Magnetic resonance (MR) imaging revealed a low intensity mass lesion in the medulla oblongata. The tumor was removed and diagnosed as a pilocytic astrocytoma. Nine years later, he was readmitted with motor weakness and dysesthesia in the right arm. MR imaging revealed a mass lesion in the cervical cord. This tumor was removed and diagnosed histologically as ependymoma. We suggest that the displacement of primitive spongioblasts with subsequent differentiation resulted in an astrocytoma and an ependymoma in adjacent areas.

Ultrastructure of ependymoma

Twenty-six ependymomas were studied by light and electron microscopy. By electron microscopy, the acellular zones around small vessels in light microscopic sections were seen to be composed of large numbers of closely packed, filament-rich, cytoplasmic processes ringing small vessels. Lumina were consistently present but many of them were too small to be seen by light microscopy. The lumina contained slender, curving microvilli and variable numbers of cilia. Their bordering cells were connected by unusually long tight junctions. Electron microscopy can be useful to establish or confirm a diagnosis of ependymoma when the light microscopic appearance is atypical, or when the tumor arises in an unusual location. The clinical data on the 26 cases has been reviewed; follow-up information was available on 23 patients.

Polysialosyl glycoconjugates defined by monoclonal antibody M6704 are expressed in human gliomas and embryonic neurons

The distribution of polysialosyl glycoconjugates defined by a monoclonal antibody M6704 (M6704 antigen) and of its O-acetylated counterpart (O-Ac-M6704 antigen) was investigated in human gliomas and in normal adult and fetal central nervous system. Among 32 gliomas, M6704 antigen was confined to the glioma cell surface and cytoplasmic processes in 21 cases, whereas O-Ac-M6704 antigen was expressed in the Golgi region in 22 cases and at the cell surface in seven cases. In adult tissues M6704 antigen was barely detectable, whereas in fetal tissues it was spatially and temporally expressed at the cell surface and along processes of post-mitotic neurons. The O-Ac-M6704 antigen first appeared in the Golgi regions of neurons at 66 gestational days and increased gradually with further maturation to adult levels. Several polysialoglycoproteins, the most dominant being 51 KD, and C-series polysialogangliosides were isolated from gliomas. These results indicate that M6704 antigen is a distinctive component expressed selectively by embryonic neurons during development and by glioma cells.

Clinical and pathological aspects of solitary spinal neurofibroma

Four cases are described of solitary spinal neurofibroma, a rare tumour of the spinal cord or nerve roots. Computerised tomography provided an accurate topographical definition of the tumour. Magnetic resonance imaging showed an increased T2-weighted signal and multiple areas of decreased T1- and T2-weighted signals centrally. The MR signals matched the histological examination which showed hyperplastic interfascicular connective tissue, pleomorphic cells, and tightly packed nerve fibres compressed by the surrounding loose connective tissue. Electron microscopy showed three types of cell: Schwann cells, fibroblast-like cells, and mast cells. The histological findings suggests that solitary spinal neurofibroma is a distinct pathological entity which could be diagnosed preoperatively from the MR images.

Expression of neuronal markers in the so-called ENU-induced schwannomas

The present data show that the so-called ENU-induced malignant schwannomas express neuronal markers. This finding supports the hypothesis that a population of tumor cells in these neoplasms are neuroblastic in nature, and suggests the classification of ENU-induced schwannomas as primitive neuroectodermal tumors.

Benign nerve sheath tumors: a light microscopic, electron microscopic and immunohistochemical study of 102 cases

One hundred and two cases of benign nerve sheath tumors (NSTs) were studied with a combined approach using routine light microscopy (LM), immunohistochemistry (IH) for myelin basic protein (MBP) and S-100 protein as well as transmission electron microscopy (TEM) with the aim of obtaining greater insight into the true nature of these neoplasms, and also to establish the importance of IH and TEM in their diagnosis. Myelin basic protein was not identified in any of these tumors, whereas S-100 protein was positive to a variable degree in both schwannomas and neurofibromas. TEM revealed that Schwann cells predominated in tumors which were strongly positive for S-100 protein and appeared as schwannomas by LM. However, neurofibromas showing a variable patchy positivity for S-100 were composed of an admixture of Schwann cells, fibroblast-like cells and intermediate cells considered to be modified Schwann cells. Perineurial cells in typical form were not seen. It is concluded that all NSTs are basically of Schwann cell origin and that the intermediate cells and fibroblast-like cells are variants of Schwann cells. The different morphological appearances and biological behaviour of schwannomas and neurofibromas may be related to some other factors like micro-environment or genetic predisposition. Further, both IH, especially for S-100 protein, and TEM play an important role in establishing their diagnosis.

Atypical subependymoma of the spinal cord: ultrastructural and immunohistochemical studies

A 76-year-old woman with a 2-year history of progressive weakness of the left arm and leg underwent a laminectomy for an intradural, extramedullary, pedunculated subependymoma involving the meninges and spinal nerve roots at C7-T1. Eight months later, another operation was necessary for an intramedullary neoplasm at C3-T4. This latter tumor consisted of small, poorly developed cells, large atypical astrocytes, and ependymal cells. Neither ependymal rosettes nor papillary formations were present. Ultrastructural studies showed some features of ependymal differentiation of the large "astrocytic" cells. This case illustrates an unusual pattern of extramedullary and intramedullary presentations of subependymoma and a spectrum of cellular differentiation of neoplastic subependymal glia.

Extrarenal Wilms' tumor with cerebellar metastasis in a four-year-old girl with spina bifida

This report documents the occurrence of an extrarenal nephroblastoma from which a cerebellar metastasis developed in a four-year-old girl with spina bifida. The second tumor became symptomatic two years after the resection of the primary, suggesting a treatment effect as a factor for the delay in the growing of the metastatic neoplasm. Histologic and ultrastructural features of the metastasis were similar to those described in Wilms' tumors of the kidney. The pathogenesis of this exceptional association, including malformation, malignancy, and unusual site of metastasis, is discussed.

Hemangioblastomas of the central nervous system--immunohistochemical and ultrastructural study

Immunohistochemical studies using immunoperoxidase staining for glial fibrillary acidic protein (GFAP), S-100 protein, and factor VIII-related antigen (VIII-RAg) were performed on 10 hemangioblastomas of the central nervous system to determine the origin of stromal cells. No cytoplasmic immunoreactivity for anti-GFAP, anti-S-100 protein, or anti-VIII-RAg was detected in most stromal cells. A small number of GFAP-positive cells were found only in the periphery of the tumor; they were thought to be trapped astrocytes or stromal cells taking up GFAP. Most stromal cells had abundant, clear cytoplasm with some microfilaments and lipid vacuoles. Cylindrical cytoplasmic processes and intermediate junctions were observed in some stromal cells, but most cells did not possess any junctional device. No stromal cell possessed any feature clearly suggesting endothelial cells or pericytes. Our immunohistochemical and ultrastructural investigations did not support the theories of stromal cell origin from astrocytes or endothelial cells. We concluded that stromal cells can be regarded as an aberrant cell type of angiogenic mesenchymal derivation.

Anaplastic ependymoma of the spinal cord in childhood. A case report

We report a 6-year-old girl with anaplastic ependymoma probably originating in the region of the conus medullaris and probably spreading retrogradely to the region of the interventricular foramen (Monro) through the cerebrospinal fluid (CSF). Since ependymoma of the spinal cord rarely occurs in children, and retrograde spreading is extremely rare, the histological features and mechanism of metastasis of the tumor are discussed.

[Immunohistochemical study on Rosenthal fibers in gliomas using anti-GFAP and anti-ubiquitin antibodies]

Immunohistochemically we investigated Rosenthal fibers (RFs) on specimen surgically removed from patients with glioma (three cerebellar astrocytomas, three optic gliomas, two spinal cord astrocytomas, one spinal ganglioglioma). Pathological diagnoses were pilocytic astrocytoma, fibrillary astrocytoma, and ganglioglioma. We utilized sections from the formalin-fixed paraffin-embedded tissues and stained them with H & E, PTAH, PAS as well as with anti-GFAP (glial fibrillary acidic protein) antibody (Ab) and two anti-ubiquitin Abs...anti-PHF (paired helical filament) monoclonal Ab (DF2) which recognizes ubiquitin (H. Mori in Science) and anti-ubiquitin polyclonal Ab provided by Dr. Haas. The primary antibodies were diluted with Tris-saline as follows: anti-GFAP (1:500), DF2 (culture medium without dilution), anti-ubiquitin (2 micrograms/ml). Sections were deparaffinized and incubated with primary antibodies overnight at room temperature. They were visualized by the avidin-biotin-peroxidase complex (ABC) procedure (Vectastain, Vector, USA) and counterstained with hematoxylin. Negative control sections were treated by omitting the primary antibodies. In the representative specimen we compared H & E, anti-GFAP and anti-ubiquitin staining on 3 microcrons serial sections. RFs were eosinophilic (bright red on H & E), purply-stained with PTAH (metachromasia), black with Heidemhein's iron-hematoxylin, and negative with PAS. Anti-GFAP Ab stained glial filaments diffusely in the cytoplasm and cell process of astrocytomas in every case. The peripheral parts of most RFs were intensely stained with anti-GFAP. The whole part of some RFs showed dark staining, and no part of a few RFs showed positive reactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Subependymoma of the thoracolumbar cord. Case report

Subependymomas are benign, usually asymptomatic, intraventricular tumors, the origin of which remains controversial. Spinal cord subependymomas are rare: a literature review yields 10 previous cases which are critically appraised in this report. A case of thoracolumbar intramedullary subependymoma is reported, and the histology, ultrastructure, and pre- and postoperative management are reviewed. Awareness that subependymomas may occur as a separate entity in the spinal cord should lead to increased frequency of diagnosis and a better understanding of the biological behavior of these tumors.

[Immunohistochemical study of schwannoma--with respect to the histogenesis of Antoni B area]

Sixty two cases of schwannoma were studied immunohistochemically and ultrastructurally for further understanding of the histogenesis of Antoni B area. For immunohistochemical study, the author used the antibodies against fibronectin (FN), factor XIIIa (XIIIa), and collagen type I and III. FN and XIIIa were positive with a fibrillar pattern in Antoni B area. Collagen type I and III were positive in the extracellular matrix of Antoni B area, but not in Antoni A area. Ultrastructurally, Antoni B area consisted of degenerative Schwann cells and fibroblasts. These findings closely resemble those of fibrogenesis seen in the wound healing process or in the stroma around tumor. The author concluded that the fibrogenesis occurring in Antoni B area reflects the stromal reaction against Antoni A area, in contrast to the previous studies that Antoni B area only represents degenerative change of Antoni A area.

[Electron microscopic observations of blood vessels in ependymoma]

The findings of an ultrastructural study of the blood vessels and their surrounding structures in ependymoma are demonstrated. Six surgically removed cases of ependymoma are investigated. The lumen of the blood vessels, especially in vascular rosettes is often wider than those of normal brain capillaries. The endothelial cells are structurally varied, but sometimes attenuated in many areas. Also, they often have several fenestrations. Moreover, they have increased pinocytotic vesicles and filaments, and contain occasional Weibel-Palade bodies, multivesicular bodies and other cytoplasmic organelles. The perivascular space is often wide, especially in intraspinal ependymoma, and filled with multiple layers of basal laminae permeated by electron, dense fluids. There are also collagenous fibers and Luse bodies. Basal lamina covering tumor cell surfaces is more distinct than other basal laminae. The tumor cells facing the blood vessel interestingly show structures similar to those of astrocytic vascular feet. The fenestration in the endothelial cells probably has an important role in the increased vascular permeability of ependymoma.

Intraspinal pigmented schwannoma with malignant progression

A case with recurrent pigmented intraspinal tumour with malignant progression is presented. The primary tumour grew around the nerve roots T9 and T10, was attached to dura and infiltrated the vertebral bone tissue. On light microscopy it was comprised of monomorphic cells with large amount of cytoplasmic pigment and many large pigmented globoid bodies. Mitoses were not observed. On electron microscopy, in addition to cytoplasmic melanosomes of regular size, macromelanosomes were numerous. The tumour cells were surrounded partially by basement membrane like material. On these bases a histological diagnosis of benign pigmented tumour of neural crest origin was suggested (a possible pigmented meningioma or pigmented schwannoma). The patient got a recurrence one year after the primary operation. Biopsy from the re-operation showed histologically the same type of tumour with more pleomorphic cells. Subsequently, the tumour grew progressively and metastases were observed in the lungs and in the skin. The patient died two years after the primary operation. The malignant progression of the tumour and other reports on similar tumours was most consistent with a diagnosis of malignant pigmented schwannoma and this was confirmed later on with immunohistochemical staining showing positive staining for basement membrane components, collagen type IV and laminin as well as a positive staining for S-100 protein. The present findings show that despite benign histological features these tumours can behave very aggressively and stress the need of more information on this type of tumour.

Cellular blue nevus ("melanocytoma") of the spinal meninges: electron microscopic and immunohistochemical features

A primary cellular blue nevus (melanocytoma) of the spinal canal in a 21-year-old woman is reported. Light microscopic examination revealed a melanotic neoplasm with histological patterns resembling schwannoma, dermal nevi, and neuroblastic-like tumor. The ultrastructural features of the neoplastic cells were similar to those in dermal blue nevi and melanomas. There was no evidence of arachnoidal cell differentiation. Immunohistochemistry revealed positive reactions for S-100 protein and neuron-specific enolase in many cells and no reactions for glial fibrillary acidic protein, cytokeratins, epithelial membrane antigen, 70-kD neurofilament protein, or Leu-7. Vimentin was strongly positive in the melanocytic cells as well as in the arachnoidal cells of involved meninges. The ultrastructural and immunohistochemical features support the nevoid nature of this tumor, which is frequently mislabeled as "melanotic meningioma."

Pseudoglandular schwannoma

The glandular schwannoma is a rare variant of schwannoma in which the focally occurring glands are lined by cells resembling intestinal or respiratory type epithelium, or ependyma. The schwannomas harboring these glands are usually malignant and usually arise in the setting of von Recklinghausen's disease. The case presented in this report is that of a 43-year-old man who had no evidence of neurofibromatosis, and developed a benign schwannoma that contained multiple well formed gland-like structures. The cells lining the glands, when examined ultrastructurally and histochemically, proved to be Schwann cells, a unique finding that may provide a clue to the histogenesis of the glandular schwannoma.

Ultrastructural findings in transplanted experimental brain tumors and their significance for the cytogenesis of such tumors

Tumors induced by transplacental action in the spinal cord of rats were transplanted into the brains of the same rat strain. They were followed up by electron microscopy during the first ten passages. Three architectural features were detected: First pure tumor parts, second myelin breakdown and phagocytosis, and third the resulting accumulation of resting macrophages. Architecture two and three were interpreted as result of considerable phagocytotic activity of tumor cells localized within the white substance of the brain and spinal cord. Only architecture one was considered to represent proper tumor. Since this was low differentiated and partial astrocytic differentiation only occurred around vessels to remarkable extent, the thesis is put forward that these transplacentally induced tumors correspond to human primitive neuroectodermal tumors.

A novel intradural extramedullary spinal cord tumor in young dogs

We have studied an unusual, spontaneous, intradural extramedullary spinal cord tumor in 12 dogs. Animals presented with paraparesis and ataxia early in life (11/12 ranged from 6 to 38 months of age) suggesting that these tumors may be congenital. Various breeds of dogs were represented with four cases in German Shepherds and three in retrievers; there was no sex predisposition. Post-mortem examinations revealed a single intradural mass consistently located between T10 and L2, which produced extensive compression of the spinal cord. Metastasis was never observed and significant pathological changes in other organs were lacking. Microscopic examination revealed solid sheets of ovoid to fusiform cells interspersed with areas of acinar and tubular differentiation. Some areas were rarified and focal squamous metaplasia was observed. Ultrastructural features included the presence of a continuous basal lamina, junctional complexes, microvilli and occasional cilia at the apices of acinar complexes. Immunocytochemical studies did not support a neurectodermal origin. At least 13 case reports of this entity have been previously published and have been designated ependymomas, medulloepitheliomas and neuroepitheliomas. A recent case was diagnosed as a nephroblastoma and we feel that this is an interesting and provocative diagnosis. These tumors could result from remnants of renal primordium which becomes trapped between the dura and the developing spinal cord. However, firm evidence of such a histogenesis is not yet at hand.

Paraganglioma of the filum terminale internum. Report of a case and review of the literature

A case of paraganglioma of the filum terminale is presented where normal sympathetic ganglion cells were seen in conjunction with tumour cells in a well-encapsulated tumour, suggesting a possible origin from heterotopic sympathetic ganglion.

Malignant rhabdoid tumor of the central nervous system

Originally described and most frequently reported in association with the kidney, the malignant rhabdoid tumor (MRT) is a highly aggressive neoplasm with distinctive morphologic features. Extrarenal sites reported for this neoplasm include the liver, thymus, and various soft tissue sites. Young infants are affected with rare exceptions. We report the case of a 3-month-old boy who presented with hyperirritability and increasing head size over several weeks. The patient died following a two-week hospital stay marked by development of seizures, paralysis, and apnea. At autopsy, significant findings were limited to the central nervous system. The subarachnoid space contained neoplasm throughout, with multiple areas of parenchymal invasion. A predominating intraparenchymal mass was present in the inferior cerebellum contiguous with the neoplasm in the subarachnoid space and probably represented the site of origin. Microscopically, the neoplasm was composed of a highly cellular monomorphic population of polygonal cells with roughly ovoid vesicular nuclei and conspicuous nucleoli. Variable amounts of cytoplasm were present, and many cells contained a single, well-demarcated eosinophilic hyaline globule adjacent to the nucleus. Ultrastructurally, the cytoplasmic globules were composed of whorled aggregates of intermediate filaments. Immunoperoxidase studies confirmed that the filaments were composed, at least in part, of vimentin. The morphologic and immunohistochemical features are diagnostic of MRT, an entity of unknown histogenesis that has not been reported previously as a primary neoplasm of the CNS.

Myxopapillary ependymoma of the filum terminale. A light and electron microscopic study

The histology of a myxopapillary ependymoma of the filum terminale in a 15-year-old girl was studied by light and electron microscopy. The neoplasm contained both papillary and compact areas of cell growth. The papillary regions consisted of vacuolated cuboidal cells arranged around hyaline/vascular cores that were variably mucin-positive. In the compact regions, the tumor cells were intensely immunoreactive for glial fibrillary acidic protein and occasionally formed perivascular pseudorosettes. Ultrastructural examination revealed interdigitating cell processes, sometimes resting on a basement membrane. Surface specializations included numerous microvilli and occasional cilia. The cilia had an abnormal microtubular pattern (e.g., 8 + 1, 7 + 0). The cytoplasm of the tumor cells contained numerous 7-10 nm intermediate filaments and large numbers of abnormal microtubular aggregates, consisting of 4 to 50 single microtubules enclosed by a limiting membrane. These microtubular aggregates may represent a characteristic feature of myxopapillary ependymoma of the filum terminale.

Multifocal spinal angiosarcoma after chordotomy

A male aged 60 is reported who, 5 years after chordotomy at the Th 2/3 level, developed acute paraplegia of the legs and a sensory transverse lesion due to an extradural tumour of the Th 1-4 level. Neuropathology revealed transverse necrosis of the thoracic spinal cord (Th 1-4) due to an intradural tumour at the upper thoracic and lumbar spinal levels, the thoracic malignancy arising at the site of the previous chordotomy, with a suture being observed within the tumour mass. Histology, positive immunostaining of tumour cells with Factor VIII antigen, a specific marker of endothelial cells and the ultrastructural demonstration of Weibel-Palade bodies in endothelial cells of the tumour vessels suggested a malignant mesenchymal tumour of angiosarcoma type presumably arising from the spinal meninges, and broadly invading the spinal cord. The usual relation of this extremely rare intraspinal vasoformative malignancy to previous chordotomy is discussed.

[Contribution of electron microscopy in the differential diagnosis of tumors of the meninges, brain and spinal cord]

Critical Evaluation of 200 tumours of meninges, brain and spinal cord showed that to be familiar with the ultrastructural features of meningioma and its variants was instrumental in differential diagnosis of other primary or secondary meningeal tumours (neurinoma, paraganglioma, xanthomatous and histiocytic tumours). A limited value of electron microscopy was found in astrocytoma and glioblastoma in contrast to its importance in low-differentiated ependymoma and oligodendroglioma. The examination had histogenetical and taxonomic values in medulloblastoma (CNS neuroblastoma and mixed tumours with a component featuring primitive neuroectodermal or neuroblastic differentiation). Ultrastructure was very important in the so-called primitive neuroectodermal CNS tumours where only the lack of conspicuous glial or neuroblastic differentiation confirmed the diagnosis. Electron microscopy was instrumental in rare primary CNS lymphomas as well as in some metastatic tumours.

Regulation of DNA synthesis and growth of cells derived from primary human meningiomas

We have studied the effects of insulin, epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet-derived growth factor, and steroid hormones (estradiol, progesterone, and cortisol) on human meningioma cell proliferation and DNA synthesis in a serum-free culture system. The growth factors, particularly EGF and FGF, increased DNA synthesis in a dose-dependent manner as measured by [3H]thymidine incorporation, and they stimulated submaximal cell proliferation. No individual factor or combination of factors was able to successfully reproduce the effects of 10% fetal calf serum (FCS) on cell growth, although a combination of platelet-derived growth factor (5 units/ml) and EGF (10 ng/ml) synergistically stimulated DNA synthesis to near maximal levels. In addition, serum dependency was observed in studies involving the mitogenic effects of insulin, EGF, or FGF. Both EGF and FGF (10 ng/ml) maximally stimulated cell growth in the presence of 5% FCS. The effects of steroid hormones on cell proliferation, individually or in combination with growth factors or charcoal-treated FCS, were also evaluated. Estradiol (100 nM) significantly increased cell number over control values only in the presence of charcoal-treated FCS; no effects of progesterone or cortisol on cell proliferation were observed. In conclusion, both EGF and FGF stimulated cell proliferation and DNA synthesis in human meningioma cultures in a serum-free system, whereas steroid hormones were without effect. It appears that additional serum components are required for both estradiol-stimulated growth and for maximal proliferation of human meningioma cells under serum-free conditions.

Fine needle aspiration cytology of hemangioblastoma of the spinal cord. Report of a case with immunocytochemical and ultrastructural studies

The cytologic features of a hemangioblastoma of the spinal cord diagnosed by an intraoperative fine needle aspiration (FNA) biopsy are reported in a 66-year-old man with a long-standing history of Charcot-Marie-Tooth disease. A dual population of delicate branching vascular channels associated with nearby coarsely vacuolated stromal cells was appreciated in the smears. Histologic, immunocytochemical and ultrastructural studies demonstrated three cell types comprising the tumor: endothelial cells, pericytes and stromal cells. Factor VIII-related antigen positivity, vimentin positivity and glial fibrillary acid protein negativity support the contention that all three types of tumor cells may arise from a common angiogenic mesenchymal ancestry. A discussion of the expected aspiration cytologic findings of other tumors of the spinal cord is also presented. FNA biopsy of suspected hemangioblastoma should be performed with utmost caution due to the possibility of extensive intraoperative bleeding, such as we experienced following sampling of this tumor.

Ultrastructure of chordoma. A case report

A 50-year-old male developed a sacro-coccygeal chordoma. Prior to the surgery, he had experienced back-pain, numbness of the right thigh and difficulty in voiding and defecation. Total excision of the mass was done and all symptoms were relieved. The light microscopic examination revealed a chordoma. The ultrastructural study was performed with particular interest in physaliferous cells. The fine structure disclosed the prominent associations of mitochondria and rough endoplasmic reticulum. The mitochondria showed irregularities in sizes and shapes but did not attenuate as much as previously reported. The vacuoles that were observed by light microscopy in physaliferous cells were both extra-cellular and intra-cellular and contained finely granular material of acid mucopolysaccharides probably of chondroitin type. The presence of both subplasmalemmal linear densities (SLD) and pinocytic vesicles was consistent with the histogenetic conviction that the tumor arose from mesodermal derivatives.

Myxopapillary ependymoma. A clinicopathologic and immunocytochemical study of 77 cases

The study involved 77 myxopapillary ependymomas of the spinal cord encountered during a 60-year period (1924-1983). This variant of ependymoma was, with few exceptions, limited to the lumbosacral region, particularly the filum terminale. The male:female ratio was 1.7:1, and the mean age at diagnosis was 36.4 years (range, 6-82); at presentation, 15 (19%) of the patients were in the first two decades of life. The duration of symptoms ranged from 1 month to 30 years; the most frequent complaint was low-back pain, and eight patients had undergone prior "disc surgery." Generally, myelographic block was disclosed. Preoperative cerebrospinal fluid protein levels averaged 2462 mg/dl. Myxopapillary ependymomas are slow-growing tumors that show no significant tendency to histologic dedifferentiation. Despite some variation in cytologic features and the presence of atypia and modest mitotic activity in most cases, the gross characteristics of the tumors appear to be of greater prognostic significance than the histologic features. Tumors that were encapsulated (25%) and amenable to intact, total surgical removal had a recurrence rate of 10%, whereas those that were removed either piecemeal (34%) or subtotally (41%) had recurrence rates of 19%. Overall survival, however, was more closely related to residual disease; total removal of tumor, whether intact (encapsulated) or piecemeal, resulted in longer survival (19 years) than did subtotal resection (14 years). Patients who died (6.5%) did so after a prolonged course marked by multiple recurrences. Radiotherapy may be of particular benefit to patients whose tumors are not amenable to intact total removal.

Myxopapillary ependymoma. A clinicopathologic and immunocytochemical study of 77 cases

The study involved 77 myxopapillary ependymomas of the spinal cord encountered during a 60-year period (1924-1983). This variant of ependymoma was, with few exceptions, limited to the lumbosacral region, particularly the filum terminale. The male:female ratio was 1.7:1, and the mean age at diagnosis was 36.4 years (range, 6-82); at presentation, 15 (19%) of the patients were in the first two decades of life. The duration of symptoms ranged from 1 month to 30 years; the most frequent complaint was low-back pain, and eight patients had undergone prior "disc surgery." Generally, myelographic block was disclosed. Preoperative cerebrospinal fluid protein levels averaged 2462 mg/dl. Myxopapillary ependymomas are slow-growing tumors that show no significant tendency to histologic dedifferentiation. Despite some variation in cytologic features and the presence of atypia and modest mitotic activity in most cases, the gross characteristics of the tumors appear to be of greater prognostic significance than the histologic features. Tumors that were encapsulated (25%) and amenable to intact, total surgical removal had a recurrence rate of 10%, whereas those that were removed either piecemeal (34%) or subtotally (41%) had recurrence rates of 19%. Overall survival, however, was more closely related to residual disease; total removal of tumor, whether intact (encapsulated) or piecemeal, resulted in longer survival (19 years) than did subtotal resection (14 years). Patients who died (6.5%) did so after a prolonged course marked by multiple recurrences. Radiotherapy may be of particular benefit to patients whose tumors are not amenable to intact total removal.

Central nervous system involvement in congenital visceral fibromatosis

Congenital visceral myofibromatosis is an uncommon disorder characterized by multiple tumors of myofibroblastic origin in the neonatal period. The natural history of the disorder has been well delineated. The myofibroblast is the cell of origin of the tumor. This is a report of a patient in whom multiple mesenchymal tumors occurred in the CNS as well as in other organs. Light and electron microscopic findings of the CNS lesions are similar to those of the somites and viscera.