Neuropathology and prognosis of foetal brain tumours.

A survey of brain tumours that had been diagnosed prenatally by foetal sonography yielded 89 cases. The most commonly found tumour entities were teratomas (53.9%), glioblastomas (14.6%), lipomas (9. 0%), plexus papillomas (7.9%) and craniopharyngiomas (5.6%). The mean gestational age at ultrasound diagnosis was 30.0 weeks, ranging between 25.4 weeks in craniopharyngiomas and 35.3 weeks in lipomas. Girls were more frequently affected (57.4%; P < 0.05). The average maximum tumour size at diagnosis was 6.5 cm, ranging between 1.6 cm in lipomas and 8.2 cm in teratomas. Tumours diagnosed between 1979- 1988 accounted for 29.2% of all cases and were larger when identified than the ones reported between 1989- 1998 (5.9 vs 8.4 cm; P = 0.08). Of all patients, only 18.8% were alive after the first week and 10.5% after the 1st year of life. Prognosis was particularly poor among foetuses with brain tumours detected before 30 weeks' gestation of which 96.9% died. Significantly longer survival was found for lipomas (12.0 vs 3.8 months), tumour detection after gestational age of 30 weeks (6.3 vs 1.2 months) and in cases reported after 1988 (5.3 vs 2.9 months, all P < 0.05). Cytogenetic data was given for eight teratomas of which three showed a pathological and five cases a normal karyotype for both foetus and tumour. In conclusion, foetal brain tumours are rare neoplasms of whose cytogenetics little is known. They are mainly detected at the beginning of the third trimester of pregnancy with teratomas being the most common entity. Foetal brain tumours have a mainly unfavourable clinical outcome. However, their prognosis has improved in the last decade.