ABSTRACT
Choroid plexus carcinomas are rarer than papillomas by a ratio of 1:5.15,38 Unlike carcinomas that arise elsewhere in the body, choroid plexus carcinoma is primarily a tumour of childhood with 70 per cent occurring before 2 years of age; the median age of occurrence is 26-32 months.6 Adult examples are exceedingly rare. Most choroid plexus carcinomas arise in the lateral ventricles with rare exceptions.10,53
In terms of tumour location, 40-50 per cent of choroid plexus tumours arise in the lateral ventricle, 5-10 per cent in the third ventricle and 40 per cent in the fourth ventricle.38,42,47 Rare extraventricular locations have been described, including the cerebellopontine angle, cerebellomedullary cistern, suprasellar cistern and even the sacral canal.31,33,43,52,57 The age distribution of patients with choroid plexus tumours varies by site.23 Whereas approximately 80 per cent of tumours in the lateral ventricles occur in children, tumours in the fourth ventricle are more evenly distributed across all age groups. Meta-analysis has shown a significant correlation between age and tumour location with a median age at diagnosis of 1.5 years for lateral and third ventricular tumours compared to 23.5 years for fourth ventricular tumours.64
