Immature teratoma arising from a benign cortical abnormality.

CASE REPORT: The authors report the case of an immature teratoma of the left parieto-occipital region in a 13-year-old girl. The patient had a computed tomographic (CT) scan of the brain aged 10 months old, following a minor head injury. This demonstrated an abnormality in the same region, which had been reported as 'a cortical malformation'. DIAGNOSIS: We propose that the lesion on the original imaging is a mature teratoma or other silent dystopic germ cell element that subsequently transformed into the immature teratoma. DISCUSSION: The potential triggers for such a transformation and the management of patients with similar incidental radiological findings are discussed.