Histopathological classification of tympanosclerotic plaques

Abstract

Tympanosclerotic plaques seen in the middle ear and tympanic membrane as a sequelae of otitis media have different characteristics. Tympanosclerotic plaque consistency shows a wide range from soft to hard during surgical excision and can be classified histologically. The aim of this study is to classify surgically excised tympanosclerotic plaques macroscopically and histologically. Seventeen surgically excised tympanosclerotic tissues were examined otomicroscopically and light microscopically. Otomicroscopically, plaques were classified as type I: soft (four cases), type II: moderately hard (six cases) and type III: very hard (seven cases), according to their consistency and surgical detachment feature. Sections prepared from tympanosclerotic tissues were stained with hematoxylin-eosin, Mallory-Azan and von Kossa stains for light microscopic evaluation. In type I tympanosclerotic tissue, fibroblasts and collagen fibers were equally abundant in typical loose connective tissue. A few small calcium crystals were seen. In type II tympanosclerotic tissue, large bundles of collagen fibers, proliferation of fibroblasts and focal calcification points were seen. In type III tympanosclerotic tissue, round shaped condroblast-like cells located in lacunae and intense calcification points were evident. Tympanosclerotic tissues can be classified in respect of their morphological and histological aspects. Histological classification of tympanosclerotic tissue may inform us about the maturation of the tissue, and therefore the grade of the disease. In type I tympanosclerotic disease, even if complete resection of sclerotic tissue is performed, the underlying process may go on and new sclerotic tissue formation can be expected. Type III sclerotic tissue is associated with limited, inactive disease. Progress of the disease and the patient's benefit from surgery can be interpreted according to this classification. However, these results will need to be verified by long-term patient follow-up and comparison of histological classification and clinical audiological symptoms.