A congenital dermal and/or subcutaneous cyst lined by an epidermis with mature dermal and appendageal structures in the cyst wall.
•Cyst(s) may communicate with the overlying epidermis via a small pore
•Often found on the midline of young animals
•Lined by a stratified squamous keratinizing epithelium
•Hair and keratin are found within the cyst lumen
•Hair follicles and sebaceous glands found within the dermis that surrounds the cyst