1/7. Atypical teratoid/rhabdoid tumor of the CNS: cytopathology and immunohistochemistry of insulin-like growth factor-II, insulin-like growth factor receptor type 1, cathepsin d, and Ki-67.insulin-like growth factor (IGF)-II is a potent growth factor, normally controlled by a number of other factors, including IGF binding proteins and IGF binding protein proteases. In general, the latter increase the bioavailability of IGF by cleaving IGF binding proteins. cathepsin d (an IGF binding protein protease) was also implicated in tumor invasion. Although IGF-II was implicated in the pathogeneses of various childhood neoplasms, its significance in the pathogenesis of atypical teratoid/rhabdoid tumor of the central nervous system (ATRT-CNS) was not studied to date. We present clinicopathologic features of two cases of ATRT-CNS. In addition, formalin-fixed, paraffin-embedded tissue sections were stained immunohistochemically for IGF-II, IGF receptor type 1, cathepsin d, and Ki-67. Both tumors demonstrated diffuse strong cytoplasmic positivity for IGF-II, diffuse cytoplasmic and focal membranous positivity for IGF receptor type I, and diffuse cytoplasmic positivity for cathepsin d. The Ki-67 labeling indices were 10.0% and 1.4%. We conclude that ATRT-CNS cells express both IGF-II and IGF receptor type 1, supporting the hypothesis that autocrine/paracrine stimulation of cell growth by IGF-II might be one mechanism involved in ATRT-CNS tumorigenesis. cathepsin d expressed by the tumor cells might also be involved in both tumor cell invasion and growth. The exact pathogenesis of ATRT-CNS remains to be elucidated.- - - - - - - - - - ranking = 1keywords = rhabdoid (Clic here for more details about this article) |
2/7. Germline INI1 mutation in a patient with a central nervous system atypical teratoid tumor and renal rhabdoid tumor.We describe a four-month-old child who presented with an atypical teratoid/rhabdoid tumor of the brain and subsequently developed a renal rhabdoid tumor. Distinct histologic features, immunophenotypic profiles, and deletions of chromosome 22 were supportive of two primary tumors. An identical mutation in exon 7 of the INI1 rhabdoid tumor suppressor gene was identified in both tumors, as well as in normal kidney tissue. We propose that this germline INI1 mutation predisposed the child to the development of both malignancies. These findings lend support to the hypothesis that rhabdoid tumors in all sites have a common genetic etiology.- - - - - - - - - - ranking = 1.6keywords = rhabdoid (Clic here for more details about this article) |
3/7. Complex rearrangement of chromosomes 6 and 11 as the sole anomaly in atypical teratoid/rhabdoid tumors of the central nervous system.Atypical teratoid/rhabdoid tumor of the central nervous system is a rare childhood tumor with a distinct histologic appearance and an aggressive clinical course. Few tumors have been analyzed cytogenetically. The only consistent chromosomal abnormality identified in some of these tumors has been monosomy or deletions of chromosome 22; in others, a normal chromosome 22 was present. The authors report an atypical teratoid/rhabdoid neoplasm of the central nervous system with a novel complex rearrangement affecting chromosomes 6 and 11 as the sole anomaly. The involvement of region 11p15 could be important in the pathogenesis of this entity.- - - - - - - - - - ranking = 1.2keywords = rhabdoid (Clic here for more details about this article) |
4/7. pathology teach and tell: central nervous system atypical teratoid/rhabdoid tumor.Atypical teratoid/rhabdoid tumor (AT/RT) is extremely malignant, highly aggressive primitive central nervous systemneoplasm of infancy with very poor prognosis. Histologically, AT/RT is defined as a polymorphous neoplasm often featuring rhabdoid, PNET, mesenchymal, and epithelial components. We report the clinical history, radiological, and pathological findings in a child affected bycentral nervous system AT/RT.- - - - - - - - - - ranking = 1.2keywords = rhabdoid (Clic here for more details about this article) |
5/7. Treatment of CNS malignant rhabdoid tumors.BACKGROUND: central nervous system (CNS) rhabdoid tumours are a highly malignant group of neoplasms usually occurring in children under 2 years of age with characteristic histopathologic findings but unclear histiogenesis and almost uniformly fatal outcome. There is still no proven curative therapy available. PROCEDURE: The clinical course and the successful outcome of therapy in two children with primary CNS rhabdoid tumour are described in this context. Both children had subtotal excision of the primary tumour and received chemotherapy based on the SIOP Malignant Mesenchymal Tumour (MMT-95) protocol with addition of triple intrathecal chemotherapy. Following this, one of the patients received high dose therapy (busulphan and thiotepa), whereas the other had craniospinal radiotherapy with a boost to the primary site. RESULTS: The treatment was reasonably well tolerated and both patients are alive with no evidence of disease 52 months and 65 months after the primary diagnosis. Their favourable outcomes are compared with those of 49 others reported in the literature. CONCLUSIONS: Intensified therapy (with autologous bone marrow transplantation and intrathecal chemotherapy) may improve the prognosis of patients with malignant rhabdoid tumour.- - - - - - - - - - ranking = 6.8294369227135keywords = rhabdoid tumour, rhabdoid (Clic here for more details about this article) |
6/7. "Polyphenotypic" tumors in the central nervous system: problems in nosology and classification.In recent years, there is increasing recognition of polyphenotypic high-grade malignancies in the non-central nervous system (CNS) tumor literature. Some of these tumors have been regarded as variants of primitive neuroectodermal tumor (PNET) or as extrarenal malignant rhabdoid tumors (MRTs). This report concerns two posterior fossa neoplasms, both of which displayed a "polyphenotypic" expression of neural, epithelial, myogenic, and glial markers, including synaptophysin, neurofilament, vimentin, glial fibrillary acidic protein, S-100, neuron-specific enolase, desmin, S antigen, MIC2, cytokeratin, epithelial membrane antigen, and carcinoembryonic antigen. One tumor showed complex intercellular junctions, cytoplasmic intermediate filaments, well-developed rough and smooth endoplasmic reticulum and golgi apparatus, cilia, and neurosecretory granules. The other neoplasm showed pools of glycogen, desmosomes, and tonofilaments. The histological and ultrastructural appearances were inconsistent with glioma, PNET, meningioma, ependymoma, choroid plexus carcinoma, sarcoma, germ cell tumor, and other tumors in the world health organization classification. Although the polyphenotype raises the issue that these may represent variants of MRT or the atypical teratoid-rhabdoid tumor, the morphologic findings in the two cases were very dissimilar. Our two cases underscore the problems in nosology and classification of polyphenotypic tumors of the CNS. This is particularly significant, as therapeutic protocols for PNET, MRT, and non-CNS polyphenotypic tumors are different. We review the literature on polyphenotypic tumors and reiterate the difficulties in precise classification of these complex tumors.- - - - - - - - - - ranking = 0.4keywords = rhabdoid (Clic here for more details about this article) |
7/7. Characterization of a primary central nervous system atypical teratoid/rhabdoid tumor and derivative cell line: immunophenotype and neoplastic properties.Primary central nervous system (CNS) atypical teratoid/malignant rhabdoid tumors (ATT/RhT) occur during early childhood and are almost invariably fatal. Expression of multiple phenotypes in ATT/RhT suggests the presence of an undifferentiated progenitor with the potential to differentiate along multiple lines. These properties have made it difficult to characterize the etiology and histogenesis of these tumors and complicate efforts to develop targeted therapies. This paper characterizes the immunophenotype of a human CNS ATT/RhT and describes the properties of a derivative cell line (Atrt95) which retained morphological and immunochemical characteristics of the parent tumor including diverse differentiation. Most tumor cells were strongly immunoreactive for glial fibrillary acidic protein, vimentin and A2B5. Scattered, large tumor cells that showed a rhabdoid phenotype were immunoreactive for synaptophysin. The morphology of cultured Atrt95 cells was heterogeneous, but often fit into 1 of 3 classes that appeared to correspond to cell populations observed within the parent tumor including: 1) tightly-packed small-cell colonies, 2) large, well-spread highly motile cells and 3) arrays of elongated cells. in vitro assays demonstrated that growth of the entire culture was anchorage-dependent but not serum-dependent. Transplantation of Atrt95 cells into the rat spinal cord resulted in tumor growth and CNS invasion. Preliminary cytogenetics study revealed complex aneuploidy but no apparent monosomy or deletions of chromosome 22. The immunophenotype of this neoplasm and derivative cell line is consistent with a primitive glioneuronal lineage and its in vitro characteristics are that of an invasive malignancy similar to the naturally occurring tumor. This unique cell line (Atrt95) provides a valuable model to study the biology and genetics of the CNS ATT/RhT.- - - - - - - - - - ranking = 1.2keywords = rhabdoid (Clic here for more details about this article) |