The pathological spectrum of solid CNS metastases in the pediatric population

Collectively, metastatic tumors are the most common malignancy encountered in the adult central nervous system (CNS), arising most often from lung, breast, skin, and gastrointestinal tract carcinomas. Limited information is available in the literature regarding solid nonhematopoietic CNS metastases in children. The authors carried out a retrospective study of pediatric metastatic neoplasms to the CNS treated in a 30-year period to characterize their frequency, common histological subtypes, and sites of origin.

The archival pathology files were searched (1981-2011) for metastatic tumors to the CNS in patients 21 years of age and younger. Pathology material was reviewed, tumors were classified by site of origin and histological subtype, and survival was evaluated.

The authors identified 26 patients with solid nonhematopoietic CNS metastases out of 1135 pediatric CNS tumors diagnosed from 1981 to 2011. Patients ranged in age from 1.5 to 20.3 years and were equally divided between sexes. Most CNS metastases were supratentorial (85%) and solitary (65%). The mean interval from primary malignant diagnosis to CNS metastasis was 27 months. Sites of origin included kidney/adrenal, bone/soft tissue, gonads, head and neck, lung, and liver. Mean survival after CNS involvement was 36.6 months. Overall 1-year and 5-year survival rates were 52% and 16%, respectively.

In neuropathology practice, nonhematopoietic pediatric CNS metastases are far less common than are nonhematopoietic adult CNS metastases, accounting for approximately 2% of all pediatric CNS tumors. The most common tumors to exhibit CNS metastasis are of kidney/adrenal origin, followed by those from bone/soft tissue. As expected, prognosis is dismal, despite aggressive therapy.