Dysplastic ganglioneuroma of the cerebellum was described in 1920 as the main manifestation of the autosomal dominant Cowden syndrome in the central nervous system. MRI shows widening of the cerebellar cortex with thickened stratification and structural disorganization. Microscopically, the regular molecular layer, Purkinje cell layer and granular cell layer of the cerebellar cortex are replaced by abnormal proliferation of sheathed axons and neurons, forming an outer layer composed of bundled sheathed axons and an inner layer composed of abnormal proliferation of neurons; the inner layer is wide and filled with poorly developed and disorganized neurons. The inner and outer layers resemble an inverted cerebellar cortex. The neurons in the inner layer are divided into two types: large, polygonal, and obvious nuclei, and small, deep nuclei, with different proportions, most cases having more small ones. In addition, there are often subarachnoid vascular abnormalities and calcifications in the lesion area. Immunolabeling showed that a few cells were derived from Purkinje cells; electron microscopic ultrastructure suggested that large neurons were derived from Purkinje cells and small neurons from granule cells. The WHO classification of neurological tumors (2000) classifies it as a neuronal and mixed neuronal-glial tumor WHO grade 1. In addition, Cowden’s syndrome itself may have multiple malformations or malformations, as well as multiple benign or malignant tumors of the skin, mucosa, or viscera, which should be examined systemically.