Congenital dermoid cysts arise from epithelial rests
trapped during midline fusion of these branchial arches whereas acquired dermoid cyst arise from epithelium implanted during trauma and they occur at the sites away from midline.
2] The cases reported in association with embedded teeth indicate the tumor may also develop from proliferation of epithelial rests
in the dental follicle.
Petrous apex cholesteatoma, which is believed to arise from congenital epithelial rests
, can lead to the accumulation of epithelial cells.