Introduction: Dysontogenetic tumors (Dts) are developmental disorders, resulting from displaced secreting skin epithelium, manifesting by cysts filled with cellular detritus, cholesterol, sebum, hair, etc. DTs generally include epidermoid cysts (ECs) and dermoid cysts (DCs), but also colloid cysts, enterogenous cysts, mature teratomas and craniopharyngiomas exists. This paper will focus on ECs and DCs only.