Michaels L
Institute of Laryngology and Otology, University College and Middlesex School of Medicine, London, U.K.
Int J Pediatr Otorhinolaryngol. 1988 Feb;15(1):51-65. doi: 10.1016/0165-5876(88)90050-x.
The sites of involvement of congenital cholesteatoma, a lesion which has recently become more frequently recognized, are reviewed from literature sources. There is a propensity for its occurrence, especially when small, in the anterior superior part of the middle ear. The same situation is the precise location of an epidermoid cell rest, the epidermoid formation (EF). This is seen in most fetal ears at the junction of the Eustachian tube with the middle ear near the anterior limb of the tympanic ring, until 33 weeks gestation, when it disappears. Its origin is traced to early fetal life from the ectoderm of the first branchial groove. In embryonic and early in fetal life it seems to act as an organizer in the development of the tympanic membrane and middle ear. It is likely that congenital cholesteatoma is derived from the EF by its continued growth instead of regression. Congenital cholesteatomas show a thinner and flatter matrix than acquired cholesteatomas, probably because the former are most frequently 'closed' and therefore subject to pressure effects from the keratin within the cyst. 'Open' forms also occur in smaller numbers. It is possible that a screening program for congenital cholesteatoma in infants might reduce the incidence of the severe, extended form of the disease.
先天性胆脂瘤是一种近年来越来越常被认识到的病变，本文从文献资料中对其受累部位进行了综述。它尤其在中耳前上部分发生，且病变较小时更易出现。同样的位置也是表皮样细胞残余即表皮样形成（EF）的确切所在。在妊娠33周之前，大多数胎儿的耳朵在咽鼓管与中耳交界处、鼓膜环前肢附近可见到这种表皮样形成，之后它便消失了。其起源可追溯到胎儿早期，源自第一鳃沟的外胚层。在胚胎期和胎儿早期，它似乎在鼓膜和中耳的发育中起组织者的作用。先天性胆脂瘤很可能是由表皮样形成持续生长而非退化演变而来。先天性胆脂瘤的基质比后天性胆脂瘤更薄更平，这可能是因为前者大多是“封闭型”，因此受到囊肿内角蛋白的压力影响。“开放型”的数量也较少。对婴儿进行先天性胆脂瘤筛查项目有可能降低该疾病严重的、扩展性形式的发病率。
