Immature teratomas of childhood. Report of 21 cases.

The benign or malignant nature and the biological behaviour of immature teratomas of childhood are difficult to predict. The age of the patient at diagnosis, the anatomical site of the tumour and the degree of immaturity are considered to be important prognostic parameters. In this study the pathological-anatomical findings and the most important clinical features of 21 patients with immature teratoma (including two with supposedly malignant monodermal teratoma with immature neuroectodermal structures) were evaluated. Significant results were: Twelve tumours occurred in infancy or infants who died in the perinatal period, the other nine tumours in children between the ages of 7 and 16 years. The most frequent anatomical sites were the ovary (6 tumours), sacrococcygeal region (4), testis (4) and mediastinum (3). In contrast to most of the tumours of other localizations, immature ovarian teratomas did not occur in children under 7 years of age (in four cases in association with gliomatosis peritonei). The immature tissue components of the tumours were mostly neuroectodermal structures. Eight tumour specimens showed grade 1, four grade 2 and nine grade 3 malignancy. Grade 3 tridermal teratomas chiefly occurred in young children, whereas two grade 3 monodermal tumours developed in older children. Immunohistochemical analysis of the neuroectodermal components showed that mature astrocytes contained glial fibrillary acid protein, whereas mature nerve cells, nerve fibres and a few groups of immature cells reacted with an antibody to neuron-specific enolase. Six of the 21 patients died; two were stillborn immature infants, two were premature infants, one died postoperatively and one died of metastatic disease. One patient with metastatic disease was alive. None of the 19 children with tridermal immature teratoma showed distant metastases. Metastatic disease was observed in only two patients with presumptive monodermal malignant teratoma. In early childhood the biological behaviour of immature teratomas is evidently similar to that of mature teratomas (provided that the tumour can be totally excised). In older children malignancy must be assumed when the tumour is located in the ovary and/or grade 3 immaturity is determined.