Michaels L
J Otolaryngol. 1986 Jun;15(3):169-74.
Thirty-seven of 68 middle ears from fetuses between 10 and 33 weeks gestation show an epidermoid formation (EF) on histological study. This is always found in exactly the same anatomical location: in the anterosuperior middle ear mucosa near the origin of the tympanic membrane and adjacent to the posterior edge of the anterior limb of the bony tympanic ring. The EF is not found after the 33rd week. It is likely that the EF is a vestigial relic of the epibranchial organ that is present in some vertebrates. Epidermoid tissue of primary and even some secondary cholesteatomas may have an origin in the EF.
对妊娠10至33周胎儿的68只中耳进行组织学研究，发现其中37只存在表皮样形成（EF）。其总是出现在完全相同的解剖位置：鼓膜起始部附近的前上中耳黏膜，与骨性鼓环前肢后缘相邻。33周后未发现EF。EF可能是某些脊椎动物存在的鳃上器官的残余遗迹。原发性甚至一些继发性胆脂瘤的表皮样组织可能起源于EF。
