Pathology of the Fetal Membranes
Localized edema with resultant cyst formation is occasionally seen on the fetal surface. Infrequently, such cysts represent amnionic epithelial inclusion cysts. These are simple cysts lined by a single layer of amnionic epithelium and usually contain clear fluid (Fig. 14.1). Rarely, an epidermal inclusion cyst or epidermoid cyst may be seen within the amnion lined by keratinizing stratified squamous epithelium (Fig. 14.2).