[Primary tumors of the choroid plexus. Frequency, localization and age].

In 30 years, from 1956 through 1985, 155 primary tumours of the choroid plexus were first reported for entry into the National Cancer Registry of the GDR, with 125 of them having been identified as plexus papillomas and 30 as plexus carcinomas. A total of 30.4 per cent of all plexus papillomas was diagnosed in patients in the first decade of life, half of them during the first year of life. A lateral ventricle was the site from which 78.9 per cent of the plexus papillomas in the first decade were recorded. Among all plexus tumours 39.4 per cent were detected only on postmortem investigation. The number of plexus tumours reported for entry into the National Cancer Registry had continuously grown in the period under review, which, however, did not necessarily suggest increasing incidence of such tumours in the general population. Possible factors of influence are discussed in some detail, for example, completeness of recording. The number of plexus tumours reported in children up to three years of age rose with significance, between 1981 and 1985. This is assumed to have possibly been the consequence of an aetiological factor. The average annual incidence (crude rate) of plexus tumours at GDR level was found to be 0.3 to one million (0.36 among males and 0.25 among females). Reasons are given that might support the assumption that real incidence has been above these values.