RESUMEN
The authors attempt to justify the term cerebral tumour of primitive germinal origin from four of their own cases and a review of the literature. They emphasise the specific features. The tumours are more common in boys and involve the pineal, the walls of the third ventricle, the hypothalamus and the posterior pituitary. Several histological types may be distinguished by the degree of differentiation but the stromal reaction, which is partly responsible for the symptoms, is always present. The clinical course of the illness is biphasic. The first is manifest by endocrine disorders and is of relatively long duration. Water homeostasis is always affected and may be associated with other hypothalamic disorders. In the second phase, neurological symptoms and raised intracranial pressure appear. Surgical removal is not always possible, but radiotherapy improves the outlook.