Cholesteatoma

CHOLESTEATOMA, a pearly tumor consisting of scales of horny substance and observed in the skin, bone, mucous membranes, and meninges; in the latter case, due to the accumulation of layered masses of keratinized epidermal scales, the tumor often takes on a special luster and whiteness, which serves as the reason for designating it as a cholesteatoma, a pearly tumor. Structure of cholesteatoma. Macroscopically, the structure of a cholesteatoma is shown in Fig. 1. Microscopically, the main mass of a cholesteatoma consists of concentrically arranged polygonal plates of anucleated epidermoid cells, between which there are, to a greater or lesser extent, cholesterol plates. This mass is surrounded by a membrane—Cholesteatommatrix. The latter consists of an outer and an inner layer. The outer layer, adjacent to the bone, consists of connective tissue poor in cellular elements, with abundant branching of vessels, and a small amount of elastic fibers. The inner layer resembles the epidermis of the skin in structure. History of the development of the theory of cholesteatoma. For the first time, a tumor-like disease of this order was found by Cruveilhier in the arachnoid membrane of the brain and named tumeur perlée (pearly tumor). Similar tumors were described in 1838 by J. Müller, and due to their layered structure and fat-reflecting appearance, they were first named by him as cholesteatomas. The first case of aural cholesteatoma, described in 1838 by Pappenheim as a case of obstruction of the tympanic cavity, concerned an 11-year-old child in whose mastoid process a greasy, shiny tumor the size of a pea was found, consisting primarily of cholesterol crystals and calcium carbonate. The basis of cholesteatoma formation lies in the proliferation of remnants of embryonic epidermis (Virchow). Based on this theory, it becomes clear why cholesteatoma is most often observed in the temporal bone, as the middle ear is formed within it as a result of the involution of the gills. Thus, a view was established of cholesteatoma as an epidermoid congenital tumor. However, the fact that in chronic purulent diseases of the middle ear, cholesteatoma is observed very

Figure 1.

often (40%) (cholesteatoma without ear disease is a rare phenomenon), forced otiatrists at one time to consider aural cholesteatoma as a "false" cholesteatoma, which is a product not of a tumor-like, but of an inflammatory order. As a result, a view was established (Habermann-Bezold) that the Cholesteatommatrix is epidermis that has invaded the middle ear cavity from the external auditory canal. In the vast majority of cases, the invasion of the epidermis of the external auditory canal into the affected mucous membrane of the middle ear occurs through a marginal perforation of the tympanic membrane (see Otitis). It was also possible to induce middle ear cholesteatoma experimentally (Berberich): cold or hot resin was instilled into the external auditory canal of animals, and a perforation was created in the tympanic membrane via paracentesis or cauterization with hot resin; the cholesteatoma formed due to the invasion of excessively regenerating epithelium in the direction of the attic. However, the pathologico-anatomical substrate is the same in both congenital and otogenic cholesteatoma. It would seem, therefore, that both these forms of cholesteatoma should have the same genesis. And indeed, the research of Manasse showed that the pathogenesis of otogenic cholesteatoma is the same as that of true (congenital) cholesteatoma. According to Manasse, the epithelium from the external auditory canal, growing towards the middle ear, does not simply cover the exposed mucosa, but has a tendency to grow intensively in the form of tongues and processes into the submucosal layer and, by proliferating, form a cholesteatomatous tumor, bulging into the middle ear cavity, sometimes covered on the outside by normal mucous membrane. An independent tendency for rapid growth of squamous epithelium along a connective tissue bed is the main point for explaining the origin of otogenic cholesteatoma. The difference between true and "false" (aural cholesteatoma) consists only in the fact that in the first case, the displacement of the epithelium occurred congenitally, and in the second, during life, caused by an inflammatory process. Considering, however, that not all chronic diseases of the middle ear cause cholesteatoma, the very question of the development of otogenic cholesteatoma must be considered open. It is possible that the development of the epidermal surface of a cholesteatoma in the middle ear sometimes proceeds without the ingrowth of epithelium from the external ear, but by way of metaplasia of the middle ear epithelium. Such, in any case, is the mechanism of cholesteatoma development in the uterus, gallbladder, urinary tract, etc. Differential diagnosis between congenital and otogenic forms of cholesteatoma: the absence in the past and present of inflammatory disease of the middle ear, objective data on having suffered such, as well as the location of the cholesteatoma in a place far removed from the middle ear cavities, for example, in the squamous part of the temporal bone (Fig. 2), speaks in favor of cholesteatoma verum. Cholesteatomas of the same order include cholesteatomas in the cerebellopontine angle (Fig. 3). Diagnosis—see Otitis. Suspicious for cholesteatoma is the finding in the lavage fluid during chronic purulent otitis of epidermoid flakes and crumbs that sink to the bottom of the vessel (a vessel with a black-colored bottom). Otoscopically, a cholesteatoma can sometimes be seen, given a sufficient size of perforation, in the form of grayish-whitish epidermoid masses protruding from the perforation opening or the cavities themselves. In doubtful cases, microscopic examination is necessary. A protracted course of acutely proceeding cases of purulent disease of the middle ear can be caused by a cholesteatoma, which can be detected by serial histological examination of the surgical material. Chronic purulent otitis, accompanied by headaches with a sensation of heaviness, fullness in the head, dizziness, and sometimes dysfunction of the facial nerve, is in the vast majority of cases complicated by a cholesteatomatous process. A great diagnostic aid is special X-ray examination, which sometimes reveals the presence of a cholesteatoma even with negligible clinical phenomena. Prognosis. Untreated cholesteatoma leads to death via meningeal or sinusogenic infection. Treatment is exclusively surgical (see Mastoiditis), leading in the vast majority of cases to a cure in the absence of damage to the meninges and brain substance.