[Diencephalic pilocytic astrocytoma with clinical onset in infancy. Biological behavior and pathomorphological findings in 11 children].

Pilocytic astrocytomas of the diencephalon with onset of signs and symptoms during the first year of life are reported in 7 boys and 5 girls. Failure to thrive was the initial manifestation in 5 infants. In 2 of them a Russel syndrome emerged. The growth rate of the tumors was slow. One child survived without treatment for 2.5 years. The survival time of the treated children ranged from 7 months to 6 years and 4 months. All children died. No obvious indications of neurofibromatosis were found. All tumors infiltrated and destroyed the hypothalamus. In addition, the tumor infiltrated the optic chiasm in 3 cases and extended into the optic nerves in 2 of them. Most of the astrocytomas were large. Their maximal diameter exceeded 10 cm in 2 children. All were pilocytic astrocytomas grade 1. The grade of malignancy was the same in recurrences as in the initial operative material. Rosenthal fibres were uncommon. It is concluded that diencephalic pilocytic astrocytomas biologically and morphologically resemble most of the pilocytic astrocytomas occurring in early life in other parts of the brain. There is, therefore, no justification for regarding them as a separate tumor entity.