Dermoid Tumors

Abstract

Dermoid tumors are congenital, nonneoplastic, inclusion lesions which have epidermal capsule and contain dermal appendages such as hair and sebaceous glands. They can occur anywhere along the neuraxis. In the literature, they are often referred to as “cysts” which refers to their histological structure and the presence of secretions (sebum) within the tumor, as well as indicates a nonneoplastic nature of these lesions. Although benign biologically, they can have malignant behavior due to their location causing mass effect and compression of vital structures or having potentially fatal complications such as abscess, spontaneous rupture, and hydrocephalus. Remak was the first to suggest displacement of epithelial rests and defective closure of the neural tube as the cause for development of these lesions. The first description of an occipital dermal sinus connected to a dermoid tumor is attributed to Olge in 1865. Later in 1897, Bostroem suggested ectopic inclusion of dermis and epidermis during embryonic development as the cause for formation of dermoids and epidermoids, respectively. This theory was further supported by Bailey in 1920 and later Citchley and Furguson in 1928 who further proposed that dermoids and epidermoids were the result of fetal inclusion of epidermal cells, depending on the depth of the layer or according to embryonic age.