Purely intramedullary spinal cord primitive neuroectodermal tumor, case report and review of the literature / Tumor neuroectodérmico primitivo espinal exclusivamente intramedular: caso clínico y revisión de la literatura

Introduction. Primitive neuroectodermal tumors (PNETs) are malign neoplasms of the central nervous system which mainly locate in cerebellum (medulloblastoma). Primary intraspinal PNETs are rare. Within this group, we have found ten cases of purely intramedullary PNETs (IPNETs). In this report, we describe a new IPNET case and review the literature about these infrequent intramedullary tumors. Case report. A 17 month-old boy showed progressive decrease of motion in his lower extremities. Spine magnetic resonance imaging revealed an intramedullary expansive lesion from T3 to T10. A near-total removal was performed. The pathological diagnosis was PNET. Subsequent chemotherapy was recommended. Six months after operation, holocord progression has occurred. Conclusion. IPNETs are uncommon tumors affecting children and young adults. They are characterized by recurrence, progression or intracranial dissemination. Outcome is dismal: most patients die within two years in spite of surgical resection followed by radiotherapy and chemotherapy (AU)

Introducción. Los tumores neuroectodérmicos primitivos (PNETs) son neoplasias malignas del sistema nervioso central que principalmente se localizan a nivel del cerebelo (denominadas en este caso meduloblastomas). Son muy poco frecuentes los PNETs primarios intraespinales. Dentro de este grupo, solamente hemos encontrado diez casos de PNETs exclusivamente intramedulares. En este artículo, describimos un nuevo caso de IPNET y procedemos a revisar la literatura existente sobre este tipo de tumores. Caso clínico. Se trata de un niño de 17 meses de edad que ha desarrollado una paraparesia progresiva. La resonancia magnética espinal muestra una lesión expansiva intramedular que se extiende desde T3 hasta T10. Se procedió a una extirpación macroscópica casi completa. El estudio anatomopatológico reveló un PNET. Se recomendó quimioterapia. Seis meses después de la cirugía, ha habido progresión a lo largo de la médula. Conclusión. Los PNETs exclusivamente intramedulares son raras neoplasias que afectan a niños y adultos jóvenes. Se caracterizan por la recurrencia, progresión o diseminación intracraneal. Son procesos de muy mal pronóstico, ya que los pacientes mueren en los primeros dos años a pesar de la resección quirúrgica y posterior radioterapia y quimioterapia (AU)

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Growth-inhibiting effects of intralesional docetaxel and paclitaxel on an experimental model of malignant neuroectodermal tumor.

Taxoids are effective agents against a wide variety of tumors, but their effectiveness on neuroectodermal tumors is not well-known. For this reason we have carried out an experimental study on the effect of intratumoral administration of docetaxel (DC) and paclitaxel (PC) on tumor growth, using a murine model of malignant neuroectodermal tumor. The results showed a delay in tumor growth in animals treated with PC compared with controls (dose of 5 mg/kg, three times per week every other day, forming a cycle; three cycles were completed with a break of a week between each cycle). The total dose administered to each animal was 45 mg/kg. When DC was administered, the results showed distinct tumor growth inhibition and tumor regression in 80% of animals (intratumoral administration at a dose of 5 mg/kg, three times per week every other day forming a cycle; three cycles were completed with a break of a week between each cycle). The total dose administered to each animal was 20 mg/kg. These results suggest the utility of taxoids, mainly DC, by intralesional administration, on malignant tumors of the nervous system.

Cell sensitivity to transplacental carcinogenesis by N-ethyl-N-nitrosourea is greatest in early post-implantation development.

In a clear demonstration of the changing sensitivity of the developing mammal to transplacental carcinogenesis, Ivankovic and Druckrey [S. Ivankovic, H. Druckrey, Transplacentare Erzeugung maligner Tumoren des Nervensystem: I. Athyl-nitroso-harnstoff (ANH) an BD IX-Ratten, Z. Krebsforsch. 71 (1968) 320-360] exposed pregnant BD IX rats to a pulse of N-ethyl-N-nitrosourea (ENU), a reactive carcinogen with a half-life of 20 min. No tumors were seen with ENU exposure before gestation day 12, but the multiplicity of neurogenic tumors increased steadily thereafter and was greatest with treatment on day 20, followed by a decline in sensitivity for the last three days of gestation. Similarly, a transplacental study of ENU in the Syrian hamster [B.A. Diwan, S. Rehm, J.M. Rice, Age- and dose-dependent transplacental carcinogenesis by N-nitrosoethylurea in Syrian golden hamsters, J. Cancer Res. Clin. Oncol. 122 (1996) 643-652] found that the numbers of tumors induced were greatest after exposure of late fetal stages. While these observations suggested that embryonic cells are refractory to carcinogenesis, an alternative explanation could be that a significant tumor yield was not observed because too few target cells were present in the embryo. I have resolved this issue by combining these published data with others on the numbers of neuroectodermal cells in the developing BD IX rat brain [R. Müller, M.F. Rajewsky, Elimination of O6-ethylguanine from the DNA of brain, liver, and other rat tissues exposed to ethylnitrosourea at different stages of prenatal development, Cancer Res. 43 (1983) 2897-2904] and total cell counts of successive developmental stages of the Syrian hamster fetus [P.J. Donovan, G.T. Smith, Cell sensitivity to transplacental mutagenesis by N-ethyl-N-nitrosourea is greatest during early gestation in the Syrian hamster, Mutation Res., 1999, this issue], allowing the risk per cell at different stages of gestation to be calculated. Sensitivity to carcinogenesis was found to be greatest early in gestation and to decrease as gestation proceeds. For the rat model, tumor frequency per cell changed from 1.3x10(-6) at day 12 exposure to 2.6x10(-8) at day 23 exposure, a 50-fold decrease. For the hamster model, the tumor-initiation rate decreased 1250-fold from 1.2x10(-5) at day 7 exposure to 9.6x10(-9) at day 13 exposure. Thus, two independent experiments with different rodent species demonstrate that sensitivity of individual cells to damage leading to transplacental carcinogenesis is greatest in the early fetus and lessens markedly as gestation proceeds, in parallel with changing sensitivity to mutation (Donovan et al., Mutat. Res., this issue).

Effect of dietary vitamin A or N-acetylcysteine on ethylnitrosourea-induced rat gliomas.

It is our hypothesis that low grade gliomas are the glial counterparts of other precancerous lesions such as colon polyps and, therefore, suitable targets for chemoprevention. Steps in the molecular progression of gliomas have been described, indicating that an accumulation of abnormalities is required for progression to a high grade and interruption of this progression might be possible. An animal model of chemical glial carcinogenesis was used to test this hypothesis. Pregnant rats were injected intravenously with ENU (ethylnitrosourea) on the 18th day of gestation to induce gliomas in the offspring, which were randomized to receive control diet, diet supplemented with vitamin A palmitate, or diet supplemented with N-acetylcysteine. Animals exposed to ENU and receiving a control diet developed brain tumors and had a shortened life expectancy compared with rats unexposed to ENU. The animals treated with NAC showed no statistically significant delay in the time to tumor and no change in the histologic grade of the tumors when compared with animals receiving control diet, but the time to death from any cause of NAC treated animals differed significantly from untreated animals. Animals receiving high dose VA had statistically significantly prolonged time to tumor, survived significantly longer than untreated animals, but had no reduction in the total number of tumors or change in the histologic grade of their tumors. The theoretical basis of these results is likely due to the putative mechanism of action of these agents. These data indicate that glioma chemoprevention is possible and deserves further exploration.

Effects of barbital on neuro-oncogenesis in a transplacental carcinogenicity model using F344 rats.

Effects of barbital (BB) on neuro-oncogenesis were examined in a rat transplacental carcinogenesis model. Pregnant F344 rats were divided into 7 groups. Dams in group I received subcutaneous injections of 10 mg/rat 1-butyl-1-nitrosourea (BNU) on the days 15, 18 and 21 of pregnancy and dams in groups II-IV, 1mg/rat BNU on the same time schedule. In addition to the treatment with BNU, dams in group IV were given 0.125% BB solution as their drinking water from the day 12 of pregnancy to parturition. Offspring in groups III and IV received 0.125% BB solution as drinking water from 4 weeks of age until the termination of the study. Animals in groups V and VI were given 0.25% and 0.125% BB solutions, respectively, in the peri- and postnatal period without BNU treatment. Dams in group VII received 250 mg/kg BB subcutaneously on the days 15, 18 and 21 of pregnancy. Offspring in all groups were observed until 105-116 weeks of age. High yields of neurogenic tumors, such as gliomas and neurinomas, were observed in group I. In groups II, III and IV, single cases of a chordoma, a granular cell tumor, and a neurinoma and a malignant reticulosis, which are known to occur spontaneously, were noted, although no gliomas were found. No neurogenic tumors were observed in groups V-VII. With regard to lesions other than those in neurogenic organs, a significant increase in liver tumors was observed in group III compared to group II. In contrast, lung tumors were not found in group III, while they were observed in groups II and IV. These results suggest that BB has no neuro-carcinogenic activity in the rat transplacental carcinogenesis model.