1/5. Radiation-induced brain calcification: paradoxical high signal intensity in T1-weighted MR images.BACKGROUND: Irradiation to the central nervous system (CNS) in childhood is known to induce cerebral calcification after a latent period. Calcification has been generally found to show nil or a reduction in signal intensity in magnetic resonance (MR) images. However, we have studied three patients with radiation-induced brain calcification, who manifested increased signal intensity on T1-weighted MR images. METHOD: Three girls had each been diagnosed as having a suprasellar germ cell tumour and were treated with conventional fractionated radiotherapy in their childhood. In one case, chemotherapy was given prior to the CNS irradiation. FINDINGS: All three patients survived their disease, and a follow-up CT scan revealed calcification in the brain, which has shown an increased signal intensity in the T1-weighted images of MR. INTERPRETATION: Cerebral calcification may be presented as a high signal intensity in the T1-weighted MR images. This may be explained by a surface-relaxation effect by the calcium salt particle, precipitated in the brain due to radiation-induced mineralising microangiopathy.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |
2/5. Primitive neuroectodermal tumors after prophylactic central nervous system irradiation in children. association with an activated K-ras gene.Three patients had supratentorial malignant brain tumors 7 to 9 years after prophylactic central nervous system (CNS) treatment for acute lymphocytic leukemia or malignant T-cell lymphoma. Therapy was administered at the age of 3 to 8 years and included cranial irradiation (total dose, 1800 to 2400 cGy) and intrathecal methotrexate. The brain tumors had histologic and immunohistochemical features of primitive neuroectodermal tumors (PNET), including neuroblastic rosettes, rhythmic arrangement of tumor cells, and immunohistochemical expression of glial, and in one patient neuronal, marker proteins. Using polymerase chain reaction-mediated dna amplification from paraffin-embedded tissues and subsequent dna sequence analysis, an activating point mutation was detected in the K-ras protooncogene in one tumor. This mutation was a G to A transition in position 2 of codon 12, substituting aspartate (GAT) for glycine (GGT). This type of mutation has not been observed before in human brain tumors, but it is frequent in radiation-induced murine lymphomas. These observations suggest that PNET can be induced after completion of the embryonal and fetal development of the human CNS. Oncogene-activating point mutations may represent a pathogenetic mechanism involved in the genesis of radiation-induced brain tumors.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |
3/5. Cutaneous toxicity of autologous bone marrow transplantation in nonseminomatous germ cell tumors.High doses of carboplatin or cisplatin combined with cyclophosphamide and etoposide followed by autologous bone marrow transplantation (ABMT) rescue have been used in the treatment of testicular tumors that have had a bad prognosis. Unusual cutaneous complications, evoking radiation-induced dermatitis, have been seen in two of eight patients with the same regimen. This new type of toxicity seems to be related to high-dose combination chemotherapies. Good results in the treatment of patients with testicular tumors on relapse who continue to respond to chemotherapy lead to the extension of this type of schedule and cutaneous toxicity will probably develop.- - - - - - - - - - ranking = 0.5keywords = radiation-induced (Clic here for more details about this article) |
4/5. Malignant mixed mesodermal tumor of bladder occurring after radiotherapy for cervical cancer: report of a case.A rare case of radiation-induced malignant mixed mesodermal tumor of the bladder is reported. A 78-year-old woman complained of hematuria, which originated from a polypoid tumor in the bladder 15 years after radiotherapy for squamous cell carcinoma of the uterine cervix. The bladder tumor recurred 9 months after resection and partial cystectomy then was performed. Histological findings revealed malignant mixed mesodermal tumor composed of carcinomatous and sarcomatous elements. The former element consisted mainly of transitional cell carcinoma with occasional foci of squamous metaplasia and glandular differentiation, while the latter consisted of spindle cell sarcoma showing partly cartilaginous and osseous differentiation. The histogenesis of malignant mixed mesodermal tumor of the bladder also is discussed.- - - - - - - - - - ranking = 0.5keywords = radiation-induced (Clic here for more details about this article) |
5/5. Homozygous p53 gene mutation in a radiation-induced glioblastoma 10 years after treatment for an intracranial germ cell tumor: case report.OBJECTIVE: Radiation-induced glioma is a rare but serious complication of radiotherapy. Underlying radiation-induced mutations in oncogenes or tumor suppressor genes have not previously been described. CLINICAL PRESENTATION: A 16-year-old female patient developed a glioblastoma in the right frontal lobe 10 years after treatment of a suprasellar germ cell tumor with 50 Gy ionizing radiation. The glioblastoma was undetectable on a high-resolution magnetic resonance image obtained 3 months before diagnosis. methods AND RESULTS: A p53 functional assay was used to examine the transcriptional competence of the p53 tumor suppressor gene. This assay scores the content of mutant p53 alleles in tumor and blood samples quantitatively as a percentage of red yeast colonies. The glioblastoma contained 95% mutant p53 alleles, whereas blood from the patient and her parents contained only normal background levels of red colonies. Sequencing revealed that the mutation in the tumor was a 3-base pair deletion affecting codons 238 and 239. Intragenic deletion within the p53 deoxyribonucleic acid binding domain is uncommon in sporadic tumors but would be entirely consistent with misrepair of a radiation-induced double-strand deoxyribonucleic acid break in this case. CONCLUSION: This is the first case in which a causative underlying genetic event has been identified in a radiation-induced glioblastoma. We infer that mutation of one p53 allele occurred at the time of radiotherapy, and the sudden appearance of the tumor 10 years later occurred after loss of the remaining wild-type allele and/or other genetic alterations, such as chromosome 10 loss and epidermal growth factor receptor gene amplification.- - - - - - - - - - ranking = 3.5keywords = radiation-induced (Clic here for more details about this article) |