[Neonatal tumours and congenital malformations].

INTRODUCTION: The association between pediatric cancer and congenital abnormalities is well known but, there is no exclusive data on the neonatal period and the underlying etiopathogenic mechanisms are unknown.
OBJECTIVES: First, to analyze the frequency of neonatal tumours associated with congenital abnormalities; and second, to comment on the likely etiopathogenic hypotheses of a relationship between neonatal tumours and congenital abnormalities. MATERIALS AND
METHOD: Historical series of neonatal tumours from La Fe University Children's Hospital in Valencia (Spain), from January 1990 to December 1999. Histological varieties of neonatal tumours and associated congenital abnormalities were described. A systematic review of the last 25 years was carried out using Medline, Cancerlit, Index Citation Science and Embase. The search profile used was the combination of "neonatal/congenital-tumors/cancer/neoplasms" and "congenital malformations/birth defects".
RESULTS: 72 neonatal tumours were identified (2.8% of all pediatric cancers diagnosed in our hospital) and in 15 cases (20.8%) there was some associated malformation, disease or syndrome. The association between congenital abnormalities and neonatal tumours were: a) angiomas in three patients: two patients with congenital heart disease with a choanal stenosis, laryngomalacia; b) neuroblastomas in two patients: horseshoe kidney with vertebral anomalies and other with congenital heart disease; c) teratomas in two patients: one with cleft palate with vertebral anomalies and other with metatarsal varus; d) one tumour of the central nervous system with Bochdaleck hernia; e) heart tumours in four patients with tuberous sclerosis; f) acute leukaemia in one patient with Down syndrome and congenital heart disease; g) kidney tumour in one case with triventricular hydrocephaly, and h) adrenocortical tumour: hemihypertrophy. The publications included the tumours diagnosed in different pediatric periods and without unified criteria to classify the congenital abnormalities. Little data exist on the neonatal period and the majority are from medical institutions registers. The prevalence varies from 15 to 31.6%. To explain this association, the hypotheses are based on prenatal exposures (preconceptional and transplacental exposure), to mutagenic and carcinogenic risk factors.
CONCLUSIONS: Neonatal tumours are more often associated to congenital abnormalities than other pediatric cancers. The inclusion and classification criteria needs to be unified to better understand the association between the neonatal tumours and congenital abnormalities. The environmental history in all neonatal tumours associated to congenital abnormalities, including the constitutional and environmental risk factors, will help to improve our knowledge of the underlying prenatal mechanisms and to an advance in its prevention.