1/12. Cerebellar degeneration and autoimmunity to zinc-finger proteins of the cerebellum.The serum of a patient with subacute cerebellar dysfunction was used to probe a cDNA expression library and isolate two genes: Zic1 (zinc-finger of the cerebellum) and Zic4. The patient had intrathecal synthesis of Zic antibodies, suggesting that the Zic proteins were autoantigens of the neurologic disorder. The Zic proteins are involved in cerebellar development and are reported as being preferentially expressed by medulloblastomas. It was found that the expression of Zic proteins is enriched in, but not limited to, medulloblastomas and primitive neuroectodermal tumors.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/12. Immunocytochemical demonstration of interphotoreceptor retinoid-binding protein in cerebellar medulloblastoma.Previously, immunoreactive rod-opsin and S-antigen (arrestin), two highly characteristic markers of retinal photoreceptors and pinealocytes, were shown to be present in certain medulloblastoma cells. It, thus, has been suggested that such cells differentiate along the photoreceptor lineage. This is corroborated in the present immunocytochemical investigation using antibodies against another photoreceptor-cell marker, the interphotoreceptor retinoid-binding protein (IRBP). As shown in preparations of human retina and pineal organ, IRBP can be successfully demonstrated in formalin-fixed and paraffin-embedded tissue: the IRBP immunoreaction is located to the outer and inner segments of retinal photoreceptor cells and to perikarya of certain pinealocytes. Examination of formalin-fixed, paraffin-embedded biopsy specimens of 66 cerebellar medullo-blastomas revealed varying numbers of IRBP-immuno-reactive tumor cells in 19 cases that were formerly shown to contain rod-opsin and S-antigen immunoreaction. IRBP-immunoreactive tumor cells were also found in a retinoblastoma and a pineocytoma, but not in neuroblastoma, ganglioneuroblastoma, glioblastoma, oligodendroglioma and astrocytoma. The results indicate: (1) cerebellar medulloblastomas are heterogeneous in their differentiation potential; (2) one type of medulloblastoma displays photoreceptor characteristics; (3) this type appears to be closely related to retinoblastoma and pineal cell tumors; and (4) all three types of tumors may display additional common features to be explored in future studies.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
3/12. Desmoplastic primitive neuroectodermal tumor with divergent differentiation. Broadening the spectrum of desmoplastic infantile neuroepithelial tumors.We report an unusual large, multicystic, posterior fossa neuroepithelial neoplasm involving the cerebellum, brain-stem, and quadrigeminal cistern of a 9-month-old girl. The neoplasm consisted of variably sized, sharply demarcated nests of small cells with a high nuclear-cytoplasmic ratio and moderately basophilic nuclei, embedded in a desmoplastic, immature-appearing, mesenchymal stroma. The nests contained mitoses but none were seen in the stroma. glial fibrillary acidic protein (GFAP), neurofilament protein, synaptophysin, and cytokeratin (AE-1) were expressed in the nests. Mesenchymal cells were negative for neural markers but positive for vimentin and desmin. The neoplasm was interpreted as a mixed mesenchymal and primitive neuroectodermal tumor (PNET) with histologic features reminiscent of a recently described intraabdominal desmoplastic small cell tumor. The tumor responded poorly to chemotherapy and a second operation was performed 1 year later. The second specimen bore no resemblance to the original and consisted of epithelial-like nests and clusters of neoplastic cells frequently interrupted by sinusoidal vessels. Tumor cells had medium-sized vesicular nuclei with small nucleoli, and a granular cytoplasm. Occasional less cellular islands of neuropil-like tissue contained larger cells having eccentric, vesicular nuclei with prominent nucleoli and abundant pink cytoplasm. Mitoses were not conspicuous. Many cells expressed synaptophysin, neurofilament protein, and GFAP. Neurofilament protein was strongly positive in the larger, neuron-like cells and synaptophysin stained the neuropil-like areas strongly but was less prominent in the neuronal perikarya. Unexpectedly, the neuropil-like areas expressed epithelial membrane antigen, whereas the neuronal cells were negative for chromogranin a. The peculiar histologic picture, combination of phenotypic markers, and remarkable biologic behavior of this unusual tumor defies classification according to existing nomenclature and exemplifies the broad range of phenotypes expressed by primitive neuro-epithelial neoplasms.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/12. Epithelial differentiation in medulloblastoma: comparison with other embryonal tumors of neuroectodermal origin.Three cases of medulloblastoma characterized by epithelial differentiation are described in patients 6-months-, 1-month- and 8-years-old. Histologically, tumors from the two infant patients showed a perivascular arrangement without apparent radiated cytoplasmic processes from the vessels. Tumor cells displayed round and/or pleomorphic vesicular nuclei and a more abundant eosinophilic cytoplasm than that found in classic medulloblastoma. Neither Homer-Wright rosettes nor ependymal or ependymoblastic rosettes were noted in these tumors. The tumor in the 8-year-old patient exhibited a classic medulloblastoma component intermingled with abundant eosinophilic cytoplasm forming a tubular structure. Immunohistochemically, tumor cells in all cases were positive for cytokeratin, synaptophysin, and vimentin. In the third case involving the 8-year-old patient, epithelial tumor cells were positive for cytokeratin, whereas classic medulloblastoma components were negative for cytokeratin. Positive staining for melanoma-specific antigen was seen only in the third case, where strong reactivity of tumor cells formed a tubulus. However, the classic medulloblastoma component was negative for melanoma-specific antigen. Ultrastructurally, basal laminae were observed around tumor cells in the 6-month-old patient. These morphological and immunohistochemical features suggest that medulloblastoma with epithelial differentiation is a rare but distinct variant of medulloblastoma, and that some of these tumors should show differentiation in ocular pigment epithelium.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
5/12. Cerebellar medullomyoblastoma with advanced neuronal differentiation and hamartomatous component.This report describes an unusual medullomyoblastoma which developed in the cerebellar vermis of a 6-year-old girl. Histological investigation showed a highly cellular and predominantly undifferentiated tumor. Myogenic differentiation was prominent in clusters of large tumor cells with eosinophilic cytoplasm and immunoreactivity for desmin and myoglobin. Electron microscopy revealed the presence of immature Z-bands. Immunohistochemically, numerous cells showed incipient expression of myoblastic marker antigens, supporting the view that medulloblastomas and related primitive neuroectodermal tumors possess the potential for non-neural differentiation. In addition, there was evidence of advanced neuronal differentiation, with expression of neuron-specific enolase, synaptophysin, retinal S-antigen, and the formation of ganglioid tumor cells. Occassional neoplastic cells expressed glial fibrillary acidic protein without morphologically detectable astrocytic differentiation. Associated with the neoplasm was brain tissue containing clusters of neuronal cells and focal accumulations of immature oligodendroglia-like cells which expressed neuronal marker antigens. This unusual component resembled a hamartomatous lesion and would support the hypothesis that the cerebellar medullomyoblastoma originated from a teratomatous or malformative lesion. Alternatively, this component may constitute the end stage of advanced neuronal differentiation of a primitive neuroectodermal tumor.- - - - - - - - - - ranking = 3keywords = antigen (Clic here for more details about this article) |
6/12. medulloblastoma simulating acute myeloid leukemia: case report with a review of "myeloid antigen" expression in nonhematopoietic tissues and tumors.medulloblastoma is a primitive neuroectodermal tumor arising in the posterior fossa usually in the first decade of life. Systemic metastases are infrequent at diagnosis and usually occur after surgical resection or shunt placement. We report a rare case of medulloblastoma in an 18-year-old woman who presented with headache, leukopenia, and anemia. neurologic examination was normal. bone marrow evaluation revealed primitive cells morphologically resembling blasts. By flow cytometry, these cells lacked CD45 and expressed CD13/33, CD15, CD34, HLA-DR, and strong CD56. The presence of myeloid antigens and CD34 suggested acute myeloid leukemia; however, the bone marrow core biopsy architecture and tumor cells in cerebrospinal fluid were more compatible with a nonhematopoietic tumor. Further workup revealed a cerebellar mass, and a diagnosis of desmoplastic medulloblastoma was made. To our knowledge, this is the first reported case of a nonhematopoietic small round blue-cell tumor expressing multiple myeloid antigens and CD34 by flow cytometry.- - - - - - - - - - ranking = 6keywords = antigen (Clic here for more details about this article) |
7/12. The modulation of astrocytic differentiation in cells derived from a medulloblastoma surgical specimen.Medulloblastomas are cerebellar tumors which are primarily composed of sheets of uniform, small malignant cells and may have astrocytic, neuronal or no features typical of these cell types. The assessment of astrocytic differentiation in medulloblastoma rests largely on the detection in malignant cells of glial fibrillary acidic protein (GFAP), a marker present in the later stages of normal astrocyte differentiation. It is still not known whether cells that do not contain GFAP in medulloblastomas with astrocytic differentiation correspond to highly proliferative astrocyte progenitors in maturation arrest at earlier stages of differentiation. The purpose of the current study was to examine whether cells in short term culture derived from a medulloblastoma tumor specimen with astrocytic differentiation were of the astrocytic lineage and if so, whether they represented proliferative astrocyte progenitors which would morphologically and antigenically mature in response to differentiating agents. A portion of tumor specimen from a 10-month-old child with recurrent posterior fossa medulloblastoma (RB2) that contained GFAP focally in tumor cells was grown in monolayer culture. We examined cellular structure and appearance of western immunoblotting and immunohistochemical studies for GFAP and neuron-specific enolase (NSE) in RB2 cells before and after treatment with retinoic acid (RA) and dibutyryl cyclic amp (dBcAMP). RB2 in culture consisted of small polygonal cells (93%), large flat cells (3%), and polygonal cells with cytoplasmic processes (4%). In untreated RB2, 30% of cells expressed GFAP and staining for NSE was negative. RA treatment produced flattened cells and decreased GFAP. DBcAMP reversibly induced fine cytoplasmic processes containing GFAP in 85% of cells within 96 h. Neither agent induced NSE. The results suggest that cultured cells which are derived from a medulloblastoma with astrocytic differentiation do not spontaneously differentiate but that treatment with dBcAMP suppresses proliferation, enhances cytoplasmic process formation and increases cytoplasmic GFAP. Cells in culture and in medulloblastoma tumor specimens which do not contain GFAP may represent astrocyte progenitors in maturation arrest.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
8/12. carboplatin-associated thrombotic microangiopathic hemolytic anemia.Thrombotic microangiopathic hemolytic anemia has been associated with several chemotherapeutic agents. The authors describe a patient who developed this syndrome while receiving carboplatin, an analog of cisplatin. The clinical course was marked by encephalopathy and multifocal neurologic deficits. Progressive brainstem dysfunction culminated in coma and respiratory arrest. Pathologic examination revealed widespread microvascular thrombosis, particularly severe in the heart, kidney, and brain. Although the pathogenesis of chemotherapy-related thrombotic microangiopathy remains unclear, an elevated von willebrand factor antigen and pathologic evidence of endothelial hyperplasia in this patient suggest that an abnormality of the endothelium is related to the development of the clinical syndrome.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
9/12. Melanotic medulloblastoma. A case report with immunohistochemical and ultrastructural examination.A melanotic medulloblastoma is reported with electron microscopic and immunohistochemical findings. The cerebellar tumor had seeded through the cerebrospinal fluid to cerebrum and spinal cord, spread through the dura, and metastasized to the lungs. It consisted of (i) anaplastic cells with slight neuronal differentiation, but without the fibrillary background of neuroblastomas, and (ii) epithelial islands pigments with melanin. The latter participated in the spread through the subarachnoid space, but did not extend beyond the dura. Electron microscopy revealed in the pigmented cells tight junctions and oculo-cutaneous melanin, including premelanosomes. The anaplastic cells had undistinguished organelles and only small junctions. On immunohistochemistry, the cytoplasm of the anaplastic cells was positive for neuron-specific enolase and neurofilament, and some of the nuclei were positive to S-100, confirming neuronal differentiation. The cells did not stain for glial fibrillary acidic protein, carcinoembryonic antigen, cytokeratin, alpha fetoprotein, vimentin, and epithelial membrane antigen. The melanotic cells were negative to all reagents tested, even to S-100 protein. The presence of oculo-cutaneous melanin and of neuronal elements indicate a neuroectodermal or neural crest origin.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
10/12. Immunocytochemical detection of tumours of neuroectodermal origin.Immunocytochemical methods were applied to bone marrow aspirate and cerebrospinal fluid specimens to show cellular reactivity with the monoclonal antibody UJ13A, which recognises an antigen expressed by cells of neuroectodermal origin. The antigen remained stable after air drying and appropriate fixation. In five patients with various neuroectodermal tumours the diagnostic advantages of these techniques were clear; they can be performed even when only very small amounts of diagnostic material are available.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
| | Next -> |