Fig.  Benign ovarian teratoma (dermoid cyst) containing central nervous tissue with differentiated cerebellar folia (arrow in the inset A; note hair follicles at asterisk). Purkinje cells were present forming numerous dendritic spines (s) on their dendrites (d). Regular synapses with parallel axons were developed(inset D). Many dendrites and their spines changed into their shrunken dark forms (inset C), perhaps due to hypoxia and perioperative mechanical trauma. The dark dendrites covered with spines were stainable by toluidine blue in semithin sections (inset B). (Human, ovary, in cooperation with Dr. Ales Kohout.)