Extraneural metastases of paediatric brain tumours

A survey of published cases of extraneural metastases of primary brain tumours in children under the age of 18 years revealed 245 cases; 60.7% occurred in boys and 27.3% were directly related to the placing of a shunt. The most common entities leading to extraneural metastases were medulloblastomas (56.3%), germinomas (9.8%), glioblastomas (6.9%), ependymomas (3.7%) and pilocytic astrocytomas (2.9%). While medulloblastomas were frequent among non-shunt-related metastases (69.4%), germ cell tumours were most common among shunt-related metastases (33.3%). Metastases were encountered equally often in bone (56.3%) and visceral organs (55.5%) but were markedly rarer in lymph nodes (25.3%). Medulloblastomas showed a preference for bones (88.3% of cases), germinomas for bones (77.8%) and visceral organs (66.7%), whereas ependymomas and ependymoblastomas were more frequently found in lymph nodes and visceral organs (71.5-100%). The most frequent sites of bone metastases were the pelvis (59.3% of cases with osseous lesions), femur (54%) and vertebrae (46%). Medulloblastomas preferentially spread into pelvis, femur and vertebrae, whereas germ cell tumours mainly involved pelvis, femur and ribs and glioblastomas vertebrae and pelvis. Most frequent sites of lymph node metastases were cervical (45.8% of cases with nodular lesions) and thoracic (31.3%) with 54% of children suffering from medulloblastomas and 7.9% from germ cell tumours. The most frequent organ involved in non-shunt-related metastases were the lungs (56.5% of children with visceral lesions) followed by muscle/soft tissue (26.9%), pleura (16.4%), skin (14.9%) and liver (13.4%). Among shunt-related cases, the peritoneum was the most frequent site (86.6% of children). The mean interval between primary brain tumour and occurrence of metastasis was 22.1 months with particularly grave outcomes among medulloblastomas, non-germinomatous germ cell tumours and glioblastomas (85.5-100% deceased children), whereas 60% of children suffering from germinomas were still alive at the time of reporting.