Dysplastic gangliocytoma of the cerebellum: rare differential diagnosis in space occupying lesions of the posterior fossa.

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos) is a rare space occupying lesion of the posterior fossa with some typical neuroradiological features which can be better diagnosed in the MRI era. This is the major CNS manifestation of Cowden disease. In recent years more publications underlined the association of these hamartomatous lesions. We add another patient with a dysplastic gangliocytoma of the cerebellum who also had a thyroid adenoma and fulfilled the criteria of having Cowden disease.A problem of surgical removal of these tumors is missing the borderline between tumor and healthy cerebellum tissue so that incomplete removal of the tumor is not rare. Surgical removal of these tumors in an open MRI unit would be a good indication.