Malignant oligodendroglioma arising after radiation therapy for lymphoma

Loss of heterozygosity analysis in an anaplastic oligodendroglioma arising after radiation therapy

OBJECTIVE AND IMPORTANCE

Oligodendroglial tumors rarely occur after radiation therapy. Here, we report a rare case of anaplastic oligodendroglioma arising after radiation therapy, in which genetic analysis was performed.

CLINICAL PRESENTATION AND INTERVENTION

A 41-year-old man who had received radiation therapy for a tumor of the suprasellar and pineal regions 31 years previously, presented with headache and progressive right hemiparesis. Magnetic resonance (MR) images revealed a ring-enhanced mass lesion in the left frontal lobe. Total removal of the tumor was performed through left frontoparietal craniotomy, and the histologic diagnosis was anaplastic oligodendroglioma. Using 23 microsatellite markers, the allelic status of chromosomes 1p, 10, 17p and 19q was evaluated by a PCR-based loss of heterozygosity (LOH) assay. Markers on chromosomes 1p, 17p and 19q revealed LOH, but none of the markers on chromosome 10 showed LOH. Based on the genetic analysis, this tumor was considered to be sensitive to chemotherapy. Two courses of chemotherapy, with procarbazine, ACNU and vincristine, were performed. However, tumor recurrence was detected only 3 months after the surgery. Despite additional radiochemotherapy, the tumor aggressively increased in size and the patient died with multiple recurrent tumors 1 year after surgery.

CONCLUSION

The anaplastic oligodendroglioma presented in this report showed a more aggressive clinical course than was expected from the genetic analysis. The significance of 1p and 19q LOH in radiation-induced oligodendroglial tumors might differ from that in spontaneous counterparts.

Anaplastic oligodendrogliomas after treatment of acute lymphoblastic leukemia in children: report of 2 cases

Radiation-induced brain tumors are suggested to be the late complication of acute lymphoblastic leukemia (ALL) treatment. High-grade gliomas, meningiomas, and sarcomas are the most frequent neoplasms. Secondary anaplastic oligodendrogliomas are exceedingly rare. Five cases of pure anaplastic oligodendroglioma have been reported in the literature, and only 1 case was in a child after ALL treatment. The authors present 2 cases of pediatric anaplastic oligodendroglioma after treatment of ALL. Furthermore, they performed a molecular cytogenetic study and found loss of 1p in both cases. The authors provide a review of the previous cases and discuss their findings.

Mechanisms of disease: genetic predictors of response to treatment in brain tumors

Brain tumors are currently diagnosed on the basis of their histology. The most common types in adults are astrocytomas, oligodendrogliomas and oligoastrocytomas or mixed tumors, which almost invariably lead to death. Improvements in outcome have been elusive despite intensive research. Recent findings indicate that response to conventional therapy, at least in some cases, correlates better with genetic characteristics than histopathology. An understanding of the molecular mechanisms that underlie the malignant phenotype of gliomas also provides the possibility of rational design of molecularly targeted therapies. This approach has proved successful in other areas of oncology. As many tumors have the same types of molecular abnormalities, molecular targeted therapies developed for nonbrain tumor types might be adapted for the treatment of brain tumors. There are a number of unique problems involved in treating tumors in the brain that must be overcome. The genetic predictors of response to conventional therapies, the genes and cellular mechanisms involved in glioma development, and potential therapeutic targets are reviewed. The possibility of designing tailored molecular therapy based on the molecular characteristics of the tumors is also explored.

Primary pediatric brain tumors: statistics of Taipei VGH, Taiwan (1975-2004)

BACKGROUND

The purpose of the current study was to investigate a hospital series of 986 cases of primary pediatric brain tumors in Taiwan.

METHODS

The authors reviewed the database of primary pediatric brain tumors in patients < 18 years of age collected in Taipei Veterans General Hospital (Taipei VGH) from 1975 to May 2004. Age and gender distribution, location, and classification of brain tumors were analyzed. Intracranial tumors with diagnostic imaging were included. Nontumoral lesions, cysts, and vascular malformations were excluded.

RESULTS

The mean age of these 986 patients was 7.8 years, and the male to female ratio was 1.4:1. Supratentorial (including pineal-quadrigeminal) located tumors (58.3%) was predominant to infratentorial tumors (41.1%). In these series, 886 patients had either histologic diagnosis (842 patients) or clinical diagnosis (44 patients). The most common 5 categories of tumors were astrocytic tumors (31.1%), germ cell tumors (14.0%), medulloblastomas (13.3%), craniopharyngiomas (8.3%), and ependymal tumors (5.8%). Atypical teratoid/rhabdoid tumors (AT/RTs), a rare but highly malignant tumor, were 2.1%. The high incidence of primary intracranial germ cell tumors correlated with reported series from Japan and Korea. For the remaining 100 patients without diagnostic classifications, the majority were most likely astrocytic tumors in brain stem.

CONCLUSIONS

The authors analyzed a large hospital series of primary brain tumors in children. Both histologically verified and unverified tumors were recruited to avoid selective bias. Although it was not a study of a population-based brain tumor registry, it could still be representative of primary pediatric brain tumors in Taiwan.