[Abscess of the posterior cranial fossa. Report of 4 cases].

The posterior cerebral fossa is an uncommon location for cerebral abscess. In most cases diagnosis is made at the encapsulation stage with the risk of life-threatening tonsillar herniation. The purpose of this retrospective study was to describe our experience in the management of four cases of abscess located in the posterior cerebral fossa between January 2000 and December 2004. All patients benefited from clinical examination and radiological study (CT-scan). Surgical treatment performed in all cases consisted of trepano-puncture of the abscess. The minimum duration of post-operative follow-up was 6 months. Mean patient age was 38.75 years. All patients presented infectious syndrome and intracranial hypertension. The male:female sex ratio was 3:1. A history of chronic middle ear otitis was noted in two patients. Diagnosis of abscess in the posterior cerebral fossa was confirmed by CT-scan in 2 cases. Cholesteatoma and triventricular hydrocephaly were noted in 2 cases. All patients benefited from trepano-puncture of the abscess. Bacteriologic study of pus was positive for Staphylococcus aureus in 1 case, and Providencia Sp associated with Bactéroïdes fragilis in another. Second-stage radical mastoidectomy was performed in 2 cases. One patient died. The outcome was favorable in 3 cases. Because of the small size of the posterior cerebral fossa, abscess in that location requires emergency treatment. Delay can be life-threatening due to the risk of obstructive hydrocephaly and tonsillar herniation.