Hinohira Y
Department of Otolaryngology, Ehime University School of Medicine.
Nihon Jibiinkoka Gakkai Kaiho. 1991 Jun;94(6):794-804. doi: 10.3950/jibiinkoka.94.794.
The pathogenesis of middle ear cholesteatoma has been thought to be invasion of squamous epithelium originated from the external ear skin including the tympanic membrane. There is no evidence, however, that the external ear skin has more potential to form cholesteatoma than that of other sites. In this report experimental middle ear cholesteatoma of guinea pigs originated from the external ear skin was histologically compared with that originated from the auricular skin. Cholesteatoma as dermal cyst was seen in the middle ear of almost all animals (25/28 = 89.3%), using a free skin graft (3 x 3 mm), regardless of the skin taken from superior (group A) or inferior (group B) part of the external ear, or the auricle (group C) eight weeks after skin implantation. The activity of epithelium such as keratinization was evident in group C. There is, however, no obvious difference in surrounding granulation tissues among group A, B, and C. In a half of this series, cyst wall was broken and its contents (debris) mainly consisted of keratin were put on surrounding granulation tissues three weeks after skin implantation. Striking keratinized epithelium and subepithelial inflammations in relation to the amount of debris were observed at the eighth week. These findings suggest that the external ear skin does not have specific potential to form cholesteatoma and keratin plays some roles in growth of cholesteatoma.
中耳胆脂瘤的发病机制一直被认为是源于包括鼓膜在内的外耳道皮肤的鳞状上皮的侵入。然而，没有证据表明外耳道皮肤比其他部位的皮肤更具形成胆脂瘤的潜力。在本报告中，对源自外耳道皮肤的豚鼠实验性中耳胆脂瘤与源自耳廓皮肤的中耳胆脂瘤进行了组织学比较。在皮肤植入八周后，使用游离皮肤移植片（3×3毫米），几乎所有动物（25/28 = 89.3%）的中耳都出现了作为真皮囊肿的胆脂瘤，无论皮肤取自外耳道的上部（A组）或下部（B组），还是耳廓（C组）。C组上皮的角化等活性明显。然而，A、B、C组周围的肉芽组织没有明显差异。在该系列的一半实验中，皮肤植入三周后囊肿壁破裂，其内容物（碎屑）主要由角蛋白组成，并附着在周围的肉芽组织上。在第八周观察到与碎屑量相关的显著角化上皮和上皮下炎症。这些发现表明，外耳道皮肤没有形成胆脂瘤的特定潜力，角蛋白在胆脂瘤的生长中起一定作用。
