1/9. Large cell/anaplastic medulloblastomas and medullomyoblastomas: clinicopathological and genetic features.OBJECT: medulloblastoma is the most common malignant central nervous system neoplasm found in children. A distinct variant designated large cell/anaplastic (LC/A) medulloblastoma is characterized by frequent dissemination of cerebrospinal fluid (CSF) at presentation and a more aggressive clinical course. The authors report on their examination of the clinicopathological and genetic features of seven such cases encountered at their institution. methods: Eighty cases of medulloblastomas were reviewed and seven (8.8%) of these were believed to fit the histological and immunohistochemical criteria for LC/A medulloblastoma. In three cases (43%) either desmoplastic or classic medulloblastoma was the underlying subtype, and in two cases (28%) the LC/A tumor was found within the setting of medullomyoblastoma. fluorescence in situ hybridization was used in six of the seven cases to characterize the presence of isochromosome 17q, deletion of chromosome 22q (a deletion characteristically found in atypical teratoid/rhabdoid tumors), and c-myc amplification. The patients' clinical histories revealed CSF dissemination in all cases and lymph node metastasis in one case. Isochromosome 17q was found in five (83%) of six cases. Evidence of chromosomal gains indicated aneuploidy in three tumors (50%), and amplification of c-myc was found in three tumors (50%). No 22q deletions were encountered. CONCLUSIONS: A high percentage of LC/A medulloblastomas arise within a background of typical medulloblastomas or medullomyoblastomas. As is the case in conventional medulloblastomas, the presence of 17q is a common early tumorigenic event; however, in a significant percentage of specimens there is also evidence of aneuploidy and/or amplification of c-myc. These findings indicate that LC/A morphological characteristics reflect a more advanced tumor stage than that found in pure medulloblastomas or in typical medullomyoblastomas.- - - - - - - - - - ranking = 1keywords = rhabdoid (Clic here for more details about this article) |
2/9. Congenital disseminated malignant rhabdoid tumor and cerebellar tumor mimicking medulloblastoma in monozygotic twins: pathologic and molecular diagnosis.Malignant rhabdoid tumors are highly aggressive childhood tumors. Recently, all of the malignant rhabdoid tumors, whatever their location, have been related to the inactivation of the hSNF5/INI1 gene. A subset of cerebral tumors, associated with malignant rhabdoid tumors or isolated ones arising in siblings, showed similar molecular alterations. We report for the first time in monozygotic twins a congenital disseminated malignant rhabdoid tumor in one twin and a cerebellar tumor mimicking a medulloblastoma in the other. Molecular analysis revealed similar alterations for both tumors: a deletion of exon 7 of the hSNF5/INI1 gene in one allele, and a point mutation in the same exon in the other, suggesting a common genetic pathway. Analysis of constitutional dna revealed a germline mutation. These findings are in favor of a common etiology for rhabdoid tumor and a subset of brain tumors developing in infancy.- - - - - - - - - - ranking = 9keywords = rhabdoid (Clic here for more details about this article) |
3/9. Primary intracranial atypical teratoid/rhabdoid tumor in a child: a case report.Rhabdoid tumors of the central nervous system are rare malignancies. Primary central nervous system atypical teratoid/rhabdoid tumors (ATT/RhTs) mostly occur during early childhood and are almost invariably fatal. These tumors show similar histological and radiological features to primitive neuroectodermal tumormedulloblastoma (PNET-MB) but have different biological behaviors. We report a case of primary intracranial ATT/RhT in the posterior cranial fossa of a child. Preoperative radiological diagnosis was PNET-MB, but pathological diagnosis is ATT/ RhT. The case involved a 16-month-old baby boy who presented with severe headache, vomiting, and gait disturbance. He was treated by surgical resection, chemotherapy, and radiotherapy. Despite aggressive therapy, he died 19 months after diagnosis. Clinical, radiological, and histopathological features of primary intracranial ATT/RhT are discussed with a special emphasis on the differential diagnosis from PNET-MB.- - - - - - - - - - ranking = 5keywords = rhabdoid (Clic here for more details about this article) |
4/9. Atypical teratoid/rhabdoid tumors.case reports: We describe three cases of atypical ATRT that were identified at the Children's Hospital of Eastern ontario. DISCUSSION: Over the past decade, atypical teratoid/rhabdoid tumors (ATRTs) of the central nervous system have emerged as a distinct entity. This tumor is typically misdiagnosed as a primitive neuroectodermal tumor (PNET)/medulloblastoma. The unique immunohistochemistry profile of an ATRT helps distinguish it from a PNET/medulloblastoma. This is of clinical importance because the prognosis of a patient with an ATRT is worse than that of a PNET/medulloblastoma despite aggressive surgical treatment with or without adjuvant chemotherapy and radiation therapy.- - - - - - - - - - ranking = 5keywords = rhabdoid (Clic here for more details about this article) |
5/9. Differentiation of classic medulloblastoma into metastatic large cell medulloblastoma with focal rhabdoid differentiation in the absence of posterior fossa recurrence.A case of classic medulloblastoma that metastasized, despite the absence of local recurrence, to extraneural sites 7 years after treatment is reported. The metastases were, in contrast to the primary tumor, of large cell type and displayed abortive myogenic and, in one site, also rhabdoid differentiation. The primary tumor expressed microtubule-associated protein 1B and neuron-specific nuclear protein (NeuN), and was desmin negative. The metastases were also positive for microtubule-associated protein 1B and NeuN, although the expression of the latter marker was weak and/or focal in two of four metastases and absent in the rhabdoid metastasis. They were, in contrast with the primary tumor, all strongly positive for desmin. The hSNF5/INI1 was expressed in the nuclei of all cells of the primary tumor and the metastases, including the one with rhabdoid differentiation. Two metastases were studied by cytogenetics. The composite karyotype of a large cell metastasis was 45~46,XY,add(1)(p36.1),t(2;8)(p21;q24.1),add(3)(q25),t(9;15)(q22;q13),add(12)(p11 .2), 1approximately2mar,inc[cp12]/46,XY[12], while the rhabdoid metastasis contained additional changes including monosomy 22. These findings indicate that some rhabdoid (atypical teratoid/rhabdoid) tumors of the cerebellum and medulloblastoma may be histogenetically related.- - - - - - - - - - ranking = 10keywords = rhabdoid (Clic here for more details about this article) |
6/9. rhabdoid tumor of the kidney presenting as an abdominal mass in a newborn.rhabdoid tumor of the kidney is a highly malignant tumor seen in the neonatal population with a characteristic clinical course. There are no known radiologic features to differentiate rhabdoid tumor of the kidney from other renal tumors; however, this report presents a newborn infant with rhabdoid tumor of the kidney who had a normal prenatal ultrasound at ten days prior to birth, followed by an abnormal prenatal ultrasound one day prior to birth. observation of such a rapid development of a tumor in the kidney in a fetus or an infant should raise the possibility of a highly malignant tumor such as a rhabdoid tumor.- - - - - - - - - - ranking = 3keywords = rhabdoid (Clic here for more details about this article) |
7/9. Embryonal brain neoplasms in the neonatal period and early infancy.We report on two cases of congenital primitive neuroectodermal tumors located in the posterior cranial fossa. They were symptomatic at birth with occlusive internal hydrocephalus. Clinical investigations had failed to diagnose brain tumors and had led to the suggestion of maldevelopment syndromes. In one of these children a malignant rhabdoid tumor of the kidney was operated at the age of 4 1/2 months. autopsy revealed medulloblastoma combined with a malignant rhabdoid tumor of the kidney in one case and ependymoblastoma in the other.- - - - - - - - - - ranking = 2keywords = rhabdoid (Clic here for more details about this article) |
8/9. The association of embryonal tumors originating in the kidney and in the brain. A report of seven cases.This report documents, in seven infants younger than 2 years of age, a previously unrecognized association of a renal embryonal neoplasm (malignant rhabdoid tumor in six patients and a Wilms' tumor in one) with an embryonal primary tumor originating in the central nervous system. The neuroepithelial tumors included three cerebellar medulloblastomas, one pineoblastoma, one primitive neuroepithelial tumor (probably cerebral neuroblastoma), one malignant subependymal giant cell astrocytoma, and one cerebellar medulloepithelioma with divergent glial and neuronal differentiation. There is no evidence that this association is based on the selective neoplastic transformation of embryonal cells of similar histogenetic or cytogenetic origin. The relationship between these dissimilar, embryologically unrelated tumors remains enigmatic.- - - - - - - - - - ranking = 1keywords = rhabdoid (Clic here for more details about this article) |
9/9. medulloblastoma associated with malignant rhabdoid tumor of the kidney: case report.The authors report a case of 6-month-old boy with cerebellar medulloblastoma associated with malignant rhabdoid tumor of the kidney, presenting with an abdominal mass, large head and projectile vomiting. Following removal of the renal tumor, the mass arising from the superior vermis about 6 cm in diameter was removed by a combined right occipital transtentorial and suboccipital approach. The patient had been well for 3 months after surgery followed by chemotherapy but died eventually of tumor recurrence in the abdomen. Reported cases of malignant rhabdoid tumor of the kidney associated with brain tumor are reviewed and its characteristics are discussed.- - - - - - - - - - ranking = 6keywords = rhabdoid (Clic here for more details about this article) |