Nishimura Y, Kumoi T, Sano S
Ann Plast Surg. 1985 Mar;14(3):296-300. doi: 10.1097/00000637-198503000-00015.
The external auditory canal opens medial to lateral in embryonal development. It is obvious that a developmental arrest anywhere during this stage would produce an absence or discontinuity of the canal, that is, congenital atretic ear. Whether or not the obliterative tissue has a bony structure, cholesteatoma can be formed behind it. Microtia is usually associated with an atretic meatus, and it may involve the possibility of epithelial cyst or cholesteatoma. The diagnosis can usually be made by the finding of tender swelling in the deformed auricle or its surroundings. On occasions, it may become necessary to distinguish these conditions from secondary infection of an epidermal cyst on the auricular surface. Several recurrent painful swellings on the deformed auricle in spite of conservative treatment indicate the need for routine otologic radiographs.
外耳道在胚胎发育过程中由内侧向外侧开放。显然，在此阶段的任何部位发生发育停滞都会导致外耳道缺失或中断，即先天性耳道闭锁。无论闭锁组织是否具有骨质结构，其后方都可形成胆脂瘤。小耳畸形通常与耳道闭锁相关，且可能伴有上皮囊肿或胆脂瘤形成。通常通过在畸形耳廓或其周围发现压痛性肿胀来做出诊断。有时，可能需要将这些情况与耳廓表面表皮囊肿的继发感染相鉴别。尽管进行了保守治疗，但畸形耳廓上出现数次反复疼痛性肿胀提示需要进行常规耳科X线检查。
