Epidermoids; clinical evaluation and surgical results.

Abstract

T HE EPIDERMOIDS or eholesteatomas often present opportunities for complete removal and cure. This is due to their frequent epidural position, avascular character, and extremely slow development. Our paper deals with the surgical t rea tment and results of the group of ~r epidermoids verified on the Neurosurgical Service of the Hospital of the University of Pennsylvania and the Graduate Hospital of the University of Pennsylvania since 1930. I t is not intended at this time to go into the slightly controversial etiology of these tumors, as they are now generally accepted to be the product of epithelial cell rests. Discussion has arisen concerning the better name for these tumors. At present, the term choles teatoma is synonymous with pearly and epidermoid, the latter being the term of choice. 5'15'1s A difference of opiaion also arises as to whet [er the cholesterin-containing masses, arising in the petrous portion of the temporal bone, should be classified as true tumors of the cholesteatoma group. The majority of pathologists believe these cholesteatomatous masses, often associated with chronic otitis media, to be unrelated to true epidermoid tumors. They are merely the result of some chronic inflammatory desquamative process2 '18 These are best designated by the term cholesteatoses. ''2 The fact that both epidermoids and contain cholesterin often serves to confuse their differential diagnosis. The differential point is that the dermoids contain hair or other dermal elements due to their mode of origin. Critchley and Ferguson ~ pointed out that both occur as the result of a fetal inclusion of epidermal cells which, depending on the depth of the layer or according to their embryonic age, produce an epidermoid or dermoid type of tumor. A complete review of the literature is not intended at this time, and one is referred to the more exhaustive works of Mahoney, 12 King, 1~ and Rand and Reeves. 18 However, a brief historical outline is included to reveal the development of terminology and theory of origin of these tumors. 1807--Pinson, 17 an artist in the School of Medicine of Paris, first described an epidermoid tumor from Dupuytren ' s service at the HStel Dieu. 18~9--Cruveilhier, 6 in his Anatomie Pathologique, fully described the tumor of Pinson and also a parapitui tary tumor of the same type. Because of their highly refractile and nodular surface, he gave them the name, tumeur perlde.