[Simple intraparenchymal cysts of the cerebellum. Apropos of 2 cases].

Introduction: Cysts of the posterior fossa are common in the literature, but the simple cyst is rarely considered in the differential diagnosis of these cysts.

Method: The cases of two female patients with clinical symptoms of expansive cerebellar lesion are described. These patients were explored by MRI. They were operated upon and an anatomico-pathological diagnosis was made.

Results: Both patients had an intraparenchymal cystic lesion of the cerebellum. No mural nodule and no enhancement after gadolinium injection were noted. The anatomico-pathological examination confirmed that the lesion was an intra-parenchymal simple cyst the walls of which showed no tumoral features.

Conclusion: Although this anatomico-pathological entity has not previously been described in the literature, such rare diagnosis should be borne in mind in patients presenting with a cystic tumour of the posterior fossa. MRI is of paramount importance in the evaluation of these lesions, but the anatomico-pathological diagnosis is indispensable to exclude a possible tumour.