Letter: Fetal hydantoin syndrome and neuroblastoma

Perinatal management of infant tumors and the promise of fetal surgery

PURPOSE OF REVIEW

This review outlines the current approaches to prenatal imaging, differential diagnosis, antenatal natural history, and the available treatment options for the most commonly prenatally diagnosed malignant tumors.

RECENT FINDINGS

In-utero diagnosis of fetal tumors, although still a rare event, has become more common as prenatal imaging modalities have improved. In general, this prenatal diagnosis allows more informed prenatal counseling and better perinatal planning for potentially high-risk deliveries. There are rare indications for prenatal fetal intervention.

SUMMARY

Diagnosis of a fetal tumor should prompt referral to a specialized center. Further understanding of these rare patients will require multicenter collaboration.

Neurodevelopmental anomalies in children with neuroblastoma

BACKGROUND

Case reports have associated neuroblastoma, a cancer derived from the embryonal neural crest, with aganglionosis coli and neurofibromatosis type I. The aim of the current study was to test the hypothesis that neuroblastoma is part of a global defect in neurodevelopment.

METHODS

Neuropathologic findings from autopsies of children who died of neuroblastoma during the period 1980-1995 at the Children's Hospital of Pittsburgh were reviewed for macroscopic and microscopic abnormalities. As controls, autopsies of children who had died of other primary extracranial cancers over the same time period also were studied. Medical records of neuroblastoma patients for whom autopsies were available were reviewed for clinical evidence of preexisting nonmalignant neurologic disease.

RESULTS

Of 145 children diagnosed with neuroblastoma, 49 had died, and autopsies not restricting examination of the brain had been performed on 13. Macroscopic anatomic abnormalities (a small cerebellum and the absence of the corpus callosum) were noted in one patient who was known to have been mentally retarded without having a defined syndrome. Microscopic abnormalities of cytoarchitecture were noted in that patient as well as 3 of the 12 other patients (focal cortical dysplasia [fcd], n = 3; leptomeningeal heterotopia, n = 1; abortive sulcation or flattened gyri, n = 2). None of 3 patients with only microscopic abnormalities had clinical evidence of problems with neurodevelopment. Of the 26 children with nonneuroblastoma cancers for whom complete autopsies were available, 1 infant had major macroscopic structural abnormalities of the brain. None of these patients had microscopic abnormalities (P < 0.01).

CONCLUSIONS

Children with neuroblastoma have an increased incidence of abnormalities of brain cytoarchitecture, particularly fcd. These abnormalities are generally asymptomatic and are diagnosed by histologic examination. Such abnormalities cannot be attributed to chemotherapy and are not observed in other children with non-central nervous system tumors. These findings are consistent with the concept that neuroblastoma may occur in the setting of a more global defect in neurodevelopment. A blinded review of larger numbers of cases will be needed to verify these data.

Pediatric cancer: environmental and genetic aspects

One in 600 children 0-16 years of age develop cancer, and 60% to 70% of them are cured. Projection of the data indicates that by the turn of the century, 1 of every 900 individuals between the ages of 16 and 44 years will be a cancer survivor. In the adult population, carcinogens and irradiation play a major role in oncogenesis. In the pediatric population other factors are probably dominant. Children of low socioeconomic groups, with nutritional deficiencies, are more exposed to viral infections at a very early age and have a greater chance of developing tumors such as Burkitt lymphoma or mixed cellularity Hodgkin disease. Other factors such as hormone-assisted conception or in vitro fertilization may have carcinogenic potential, although this has yet to be determined. Maternal diet during pregnancy, especially low folic acid consumption periconception, may have bearing on the fetus's risk of developing malignancy. The hazards of exposure to electric and magnetic fields from high-voltage transmission lines, home electric appliances, video display terminals, or residence near nuclear plants, although very doubtful, are included in the list of cancer promoters in children. Activated oncogenes, mutated suppressor genes, mismatch repair genes, nucleotide excision genes, and loss of imprinting genes are beginning to evolve as important factors in carcinogenesis. The more in-depth information on genetic and environmental factors should provide new data on the evolution of pediatric tumors and possibly on their prevention.

Lymphoblastic lymphoma following prenatal exposure to phenytoin

PURPOSE

Oncogenesis has been associated with prenatal exposure to phenytoin, concomitant with or independent of the fetal hydantoin syndrome. The majority of reported cases have been embryonal tumors of neural crest origin and have occurred in the first 3 years of life.

PATIENTS AND METHODS

We report a boy who was exposed to phenytoin throughout gestation and later developed T-lymphocyte lymphoblastic lymphoma, a previously unreported malignancy associated with in utero phenytoin exposure. Previously reported cases of neoplasia occurring after such exposure are tabulated.

CONCLUSION

The actual transplacental oncogenic potential of phenytoin and the epidemiology of this association are poorly understood. Phenytoin-induced alterations in lymphocyte-mediated immunosurveillance or oxidative metabolic clearance may be etiologic. Inquiry into prenatal phenytoin exposure should be done in any child who develops cancer, especially those who develop a rare tumor or present with a more common tumor at an unusually young age. Continued documentation of such cases will advance the understanding of phenytoin-associated transplacental oncogenesis.

Folate and cancer: A review of the literature

Folate, a water-soluble vitamin, part of the vitamin B complex, plays an important role in methylation reactions and DNA/RNA synthesis. This review examines the experimental and epidemiological evidence for the association between folate status and risk of cancer. Data have accumulated indicating that low folate status may promote carcinogenesis. Low folate levels are associated with cytogenetic abnormalities in vivo and in vitro. Findings from animal studies are conflicting and suggest that the effect of folate on neoplasia depends on factors such as the animal and tumor model, the type, timing, dose, and length of application of carcinogen, the stage of carcinogenesis, and the level and form of folate administered. Epidemiological studies examined the association between folate and cancer of the cervix, colorectum, lung, esophagus, and brain and suggest that low folate status may play an important role early in the neoplastic process. The potential for inhibition of precursor lesions in the cervix and colorectum, namely, cervical intraepithelial neoplasia and adenomatous polyps, respectively, is of particular interest. Additional research designed to clarify the role of folate in carcinogenesis is warranted.

Hormonal treatment in pregnancy: a possible risk factor for neuroblastoma

In the last 4 years, 24 cases of neuroblastoma were treated in the Pediatric Hematology-Oncology Unit at the Chaim Sheba Medical Center, 8 of whom were under 1 year of age. Four of them were the product of a pregnancy-induced or preserved by gonadotropins, clomiphene citrate, or progestational hormones. These drugs are known to produce a higher than normal level of estradiol or progesterone in the early stages of pregnancy. Our observation led to the hypothesis that high levels of progestational hormones given during pregnancy are a risk factor for neuroblastoma in infancy.

Anticonvulsants in pregnancy

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Parental epilepsy, anticonvulsant drugs, and reproductive outcome: epidemiologic and experimental findings spanning three decades; 2: Human studies

Evidence accumulated over the past three decades has established AEDs as human teratogens. Important developments in the delineation of these compounds as human teratogens include: the demonstration of a consistent association between in utero exposure to AEDs and an increased occurrence of single major malformations, the description of AED-induced dysmorphogenic syndromes; demonstration of a dose-response relationship, both in terms of the number and dosage of AEDs; and evidence that pharmacogenetic differences in the metabolism of AEDs are strongly correlated with the occurrence of congenital malformations. Furthermore, the experimental animal findings, having accumulated in parallel to those of human studies, strongly support the teratogenic role of AEDs. Areas that require further amplification and clarification in future studies are the relative contribution of AEDs and other factors, such as genetic predisposition and maternal seizures, particularly with respect to the occurrence of minor anomalies, growth retardation, and developmental outcome; the relative teratogenicity of specific monotherapies and polytherapies; the predictive role of pharmacogenetic differences in the metabolism of AEDs in the occurrence of structural and functional abnormalities; and characterization of the precise nature of the pharmacogenetic defect underlying the aforementioned differences in AED metabolism. Attempts should also be made in future prospective studies to monitor metabolite levels of AEDs, particularly the oxidative metabolites, in order to further elucidate the relative contribution of individual differences in metabolism in the determination of adverse fetal outcome. Similarly, further efforts should be made to assess the clinical significance of decreased growth parameters in terms of mental and neurologic development, and to ascertain whether there is any risk for such abnormalities in children who do not display overt or persistent reductions in physical growth parameters. This is critically important in light of the animal studies that have shown functional abnormalities at doses that do not necessarily produce structural defects. Future investigations would be conducted through collaborative studies that would encompass sufficiently large numbers of women to provide adequate power to the statistical analyses of the data obtained. Care would have to be exercised to establish a uniform protocol for the collaborating centers. Regionally based investigations would be preferable to studies based at special centers, in order to assess the relative role of risk factors associated with abnormal pregnancy outcomes in the epileptic population at large.(ABSTRACT TRUNCATED AT 400 WORDS)

Neuroblastoma after prenatal exposure to phenytoin: cause and effect?

We evaluated the causality of the association between intrauterine exposure to phenytoin and postnatal neuroblastoma using an in vitro lymphocyte toxicity assay for phenytoin-induced reactions in an unusual sibship. In addition, we investigated intrauterine phenytoin exposure in a case series of infants and children with neuroblastoma diagnosed over 17 years at our center. The response of lymphocytes from our index case with neuroblastoma exposed in utero to phenytoin was within the normal range, whereas the mother and a sibling with fetal hydantoin syndrome (FHS) exhibited an intermediate toxicity. None of the 188 cases of childhood neuroblastoma diagnosed between 1969 and 1988 had been exposed in utero to phenytoin, indicating that, statistically, the drug cannot be associated with neuroblastoma in more than two cases with this malignancy in our cohort, or in 1.5% of all cases of neuroblastoma. Although our data do not suggest an association between phenytoin in pregnancy and postnatal neuroblastoma, it is still possible that there is an increased risk for neuroblastoma in children with FHS.

Teratology: principles and practice

Gross anomalies of structure and/or function affect 2 to 4 per cent of all human newborns and are the leading cause of perinatal mortality in this country. Despite their significance, the etiology of most such defects remains unclear. A majority are unassociated with any identifiable cause; a small but significant percentage are attributed to heritable disorders of either a Mendelian (single gene) or chromosomal nature. Drugs and environmental exposures are currently implicated in only a small percentage of affected pregnancies. Nevertheless, an awareness of the principles of teratogenesis, an appreciation for the role--though imprecise--of placental transfer and fetal drug disposition, and avoidance of known teratogens currently offers our best hope for the study and prevention of birth defects.

The Inter-Regional Epidemiological Study of Childhood Cancer (IRESCC): past medical history in children with cancer

The Inter-Regional Epidemiological Study of Childhood Cancer (IRESCC) collected interview and medical information relating to the child's past medical experiences from parents of 555 children diagnosed with cancer and parents of 1110 unaffected matched controls. No significant associations emerged overall for ante-natal care, place and mode of delivery, length of gestation, birth weight, condition at birth, special care, neonatal procedures or breast-feeding. Few risk factors relating to previous illnesses and medication were found, although increasing numbers of illnesses appeared to be associated with an increased risk of childhood cancer, particularly acute lymphoblastic leukaemia. A highly significant excess of case children had not been immunised (p = 0.005). In general, these results indicate that past medical experiences have little influence on the development of cancer in children.

Prenatal and perinatal risk factors for neuroblastoma. A case-control study

Neuroblastoma is the most common neoplasm in children less than 1 year of age and has one of the earliest incidence peaks of all childhood cancers. Using birth registration data, a matched case-control study was undertaken to investigate potential prenatal and perinatal risk factors. Ninety-seven neuroblastoma patients who were born in Minnesota were matched with four controls each. No associations were identified for sex, race, parental age, parental education, complications of pregnancy, labor, or delivery, or the previously reported factors of birth weight greater than 4000 g or gestational duration of 36 weeks or less. In 6.6% of the cases and 0.8% of the controls, physical anomalies were noticed before discharge from the newborn nursery. Of the six anomalies reported in the cases, four were found to be the tumor itself or a complication of it. A significant protective effect (odds ratio (OR), 0.47) was noticed for a maternal history of previous fetal loss. Future studies, including biologic markers and stage stratification, may yield more insight into the cause of this disease.

Diphenylhydantoin and mitotic spindle abnormalities in cultured mouse and human cells

The present study demonstrates that the antiepileptic drug diphenylhydantoin (DPH) is capable of inducing aneuploidy but not structural aberrations in cultured mouse embryonic fibroblasts. A high concentration of 200 micrograms/ml was found to increase the percentage of hyperdiploidy from 4.8 (control) to 16.0. The treatment was found to increase mitotic indices as a consequence of a mitotic-arresting action of the drug. These effects are probably due to the effect of the drug on the structure of the mitotic apparatus. Abnormal cell divisions and mitotic disturbance were found to increase in a dose-dependent manner after DPH treatment. In a parallel study, human amnion cells were found to show similar response to DPH treatment.

Neuroblastoma

Neuroblastoma originates in the adrenal medulla or anywhere in the body that sympathetic tissue normally is present. It may present with a variety of symptoms due to primary tumor, metastatic disease, or unusual signs and symptoms such as opsoclonus-myoclonus or severe diarrhea. Despite the fact that this neoplasm responds to a variety of therapeutic modalities, it remains one of the most frustrating and difficult childhood tumors to treat and cure.

Ependymoblastoma associated with prenatal exposure to diphenylhydantoin and methylphenobarbitone

Ependymoblastoma developed in a 28-month-old girl whose epileptic mother took diphenylhydantoin and methylphenobarbitone throughout pregnancy. The child was also shown to be a genetic carrier for ornithine transcarbamylase deficiency, an x-linked inborn error of urea cycle metabolism. The possibility of transplacental carcinogenesis should be considered, as other juvenile embryonic tumors such as neuroblastoma, melanotic neuroectodermal tumor, and mesenchymoma have been reported in offspring after diphenylhydantoin use by the mother during pregnancy.

Dilantin digital defects

Diphenylhydantoin (phenytoin) is a widely used drug with multiple adverse effects, several of them cutaneous. Prenatal exposure to hydantoins may result in a spectrum of structural, developmental, and behavioral changes known as the fetal hydantoin syndrome (FHS). A patient with the dysmorphic characteristics of FHS had unusual hyperpigmentation of several fingernails, a finding which has not been described in other patients with FHS. We propose a mechanism for the dysmorphic action of phenytoin on the developing fetus, consonant with the known effects of hydantoins on collagen metabolism.

The epidemiology of cancer: an overview

The contribution of cancer epidemiology to cancer prevention is in identifying risk factors, providing clues for understanding etiologic mechanisms, and in developing the scientific rationale for the effective application of preventive measures. Cancer mortality, incidence, and survival trends over 25 years (1950-1974) in the United States are reviewed for 12 selected sites in adult men and women. If both incidence and mortality for a specific cancer site remain unchanged or change proportionately over a period of years, no major change in survival should be anticipated. The patterns of occurrence and their etiologic implications are reviewed separately in American blacks and in children and young adults. The studies of geographic pathology and of various migrant populations have provided observational "experiments of nature" that have facilitated our understanding of cancer etiology by stimulating important paths of research.

Childhood cancer and drugs in pregnancy

A study was carried out on 11 169 matched case-control pairs of children aged up to 15 years included in the Oxford Survey of Childhood Cancers to see whether an association exists between cancer in children and drugs given to their mothers during pregnancy. The mothers of children who developed cancer reported about 25% more illnesses during pregnancy than mothers of healthy control children. Two specific illnesses, pulmonary tuberculosis and epilepsy, were investigated. For these there was a higher than average case-control excess of reports and there had been a suggestion that the drugs used in treatment, isoniazid and phenytoin, might be carcinogenic. The results of this investigation provide no real evidence for any association between the drugs taken by the mothers during pregnancy and subsequent cancer in the child.