See Figure 8 in pmid:16714456. Epidermoid cysts arise from ectodermal inclusion during neural tube closure in the 3rd-5th week of embryogenesis. The microscopic cyst lining consists of stratified squamous epithelium supported by an outer layer of collagenous connective tissue. Cystic contents usually include debris, keratin, water, and cholesterol laid down in a lamellar fashion. Epidermoid cysts do not contain dermal appendages.