Dysplastic gangliocytomas of the cerebellum are usually discovered in the third or fourth decades of life (Ambler
et al., 1969; Vinchon et al., 1994; Robinson and Cohen, 2000; Wiestler et al., 2000), but patients of any age may be affected. Roessmann and Wongmongkolrit (1984) recorded the incidental discovery of one example at autopsy of a newborn, the literature containing reports of this condition presenting in older children, adolescents and adults up to 74 years of age (Ambler et al., 1969; Robinson and Cohen, 2000; Wiestler et al., 2000). There is no clear gender predilection. Associated clinical manifestations, typically protracted in their evolution and often present for years prior to lesion detection, most commonly reflect obstructive hydrocephalus with intracranial hypertension (e.g. headache, nausea, and papilledema). Cerebellar signs (such as ataxia) may be observed, as may cranial nerve deficits, unusual presentations including severe orthostatic hypotension (Ruchoux et al., 1986), tinnitus (Lobo et al., 1999), and acute subarachnoid hemorrhage (Shanley and Vassallo, 1992; Stapleton et al., 1992).