[Hygroma of the posterior cranial fossa. Case report].

Posterior fossa hygroma is a rare entity. In a series of 553 cases of surgically treated traumatic subdural lesions, reported by Jamieson and Yelland, only 14 were in the posterior fossa; of these 7 were hygromas and 7 haematomas, giving an incidence of only 1,4% of all subdural haematomas. This report describes a case of a posterior fossa hygroma, that occurred in a 16-years-old boy, 4 days after an occipital head injury.