耳硬化症の病理について

抄録

Histopathological studies of otosclerosis have been well documented by many anatomists and pathologists since the 19th Century, based on microscopic dissections of the temporal bones from Caucasian patients. The author attempts to describe the morphology and development of the normal human otic capsule for better understanding of histopathologic characteristics of otosclerosis.
Otosclerosis is a primary disease of the osseous otic capsule which consists of one or more localized foci where there have been repeated resorption and remodeling of osseous tissue. The most common location for a focus is anterior to the vestibular window. The focus may gradually invade the annular ligament and stapes, causing bony ankylosis of the stapes and impairment of hearing (clinical otosclerosis). In other instances otosclerotic focus may become quiescent in the otic capsule without causing bony ankylosis of the stapes footplate (histologic otosclerosis). Histopathologically, four stages are generally recognized in the development and progression of the otosclerotic bone change:
1. Osteoclastic destruction of endochondral bone of the otic capsule and formation of perivascular spaces which contains vascular channels and fibrous tissue.
2. Formation of immature basophilic bone.
3. The remodeling process of resorption and new bone formation resulting in a more mature acidophilic lamellar bone.
4. Formation of a highly mineralized acidophilic bone which has a mosaic-like appearance at the quiescent stage of otosclerotic lesion.
The author describes the general morphological features of otosclerosis by reviewing the literature and by presenting microphotographs of histologic otosclerosis obtained in a survey of the temporal bones from unselected Japanese ears, and clinical otosclerosis which had been collected from removed stapes footplates by stapedectomies from Japanese otosclerotic patients.