Huang J M
First Affiliated Hospital of Fujian Medical College, Fuzhou.
Zhonghua Er Bi Yan Hou Ke Za Zhi. 1993;28(4):228-30, 252-3.
Forty-nine fetuses, ranging from 12 weeks to full term of fetal age, were collected to study the epidermoid formation(EF) in the middle ear. The results showed that: 1) Sixteen of 49 fetuses had EFs in the middle ear aged 14 to 38 weeks of gestation. The structure always appeared between the anterosuperior edge of the eardrum and the anterior limb of the tympanic ring. The width and height of the EFs were 60.82 +/- 5.68 microns and 45.87 +/- 6.82 microns respectively. 2) The EFs might be classified into two types: simple EF and hyperplastic EF. Most of the simple EFs would degenerate and disappear in the late fetal stage, but a few of them might transform into hyperplastic ones. The hyperplastic EF showed more active appearance and multilayered structure, so it seemed to grow continuously, and might develop into congenital cholesteatoma.
收集了49例胎龄从12周直至足月的胎儿，以研究中耳表皮样形成（EF）。结果显示：1）49例胎儿中有16例在妊娠14至38周时中耳存在表皮样形成。该结构总是出现在鼓膜前上缘与鼓环前肢之间。表皮样形成的宽度和高度分别为60.82±5.68微米和45.87±6.82微米。2）表皮样形成可分为两种类型：单纯型表皮样形成和增生型表皮样形成。大多数单纯型表皮样形成在胎儿后期会退化消失，但少数可能转变为增生型。增生型表皮样形成外观更活跃且呈多层结构，因此似乎会持续生长，并可能发展为先天性胆脂瘤。
