Cholesteatoma is a destructive and expanding growth consisting of keratinizing squamous epithelium in the middle ear and/or mastoid process. Although these are not strictly speaking tumours or cancers they can still cause significant problems because of their erosive and expansile properties resulting in the destruction of the ossicles as well as their possible spread through the base of the skull into the brain. They are also often infected and result in chronically draining ears.
There are two types: congenital and acquired. Acquired cholesteatomas, which are more common, can be caused by pathological alteration of the ear drum leading to accumulation of keratin within the middle ear.
Less commonly the disease may be a developmental abnormality, when it grows from birth behind the ear drum, in the form of a keratin-filled cyst.
On initial inspection, an ear canal full of discharge may be all that is visible. Until the doctor has cleaned the ear and inspected the entire tympanic membrane, cholesteatoma cannot be either confirmed or excluded.
Once the debris is cleared, cholesteatoma can give rise to a number of appearances. If there is significant inflammation, the tympanic membrane may be partially obscured by an aural polyp.
The patient may commonly also have clinical signs of conductive hearing loss. Less frequently, there may be signs of imbalance or facial weakness.
If untreated, a cholesteatoma can eat into the three small bones located in the middle ear (the malleus, incus and stapes), it can result in nerve deterioration, deafness, imbalance and vertigo. It can also affect and erode, through the enzymes it produces, the thin bone structure that isolates the top of the ear from the brain, as well as lay the covering of the brain open to infection with serious complications (rarely even death due to brain abscess and septicemia).
The pathologic differences between cholesteatomatous (C-COM) and non cholesteatomatous chronic otitis media (NC-COM) have not been analyzed fully yet, and this seems to be one of the reasons for the ambiguity of the pathogenic mechanisms and prophylaxis of cholesteatoma. Although our understanding of the molecular mechanism underlying the pathogenesis of cholesteatoma is limited, one of the important pathologic processes in this entity is active proliferation of epithelial cells , which is thought to be stimulated by various growth factors .
Typical sections of C-COM and NC-COM show granulation tissue formation, including infiltration of fibroblasts, can be seen in the subepithelium and middle ear submucosa at various levels, as well as the presence of predominantly chronic inflammatory cells such as lymphocytes,monocytes, and plasma cells .
However, it is often difficult to differentiate the two entities by hematoxylin and eosin staining.
Several studies reported that various cytokines such as interleukin 1(IL-1), transforming growth factorα, and keratinocyte growth factor (KGF) are involved in epithelial proliferation in middle ear cholesteatoma.
Co expression of KGF and its receptor (KGFR) seemed to induce the proliferation of epithelial cells in primary and recurrent C-COM .
Keratinocyte growth factor is a mesenchymal cell derived paracrine growth factor that specifically stimulates epithelial cell growth and is thought to be secreted by fibroblasts present mainly in the stroma and binds to KGFR; the latter has only been detected on the surface of epithelial cells .
The aims of the present study were to compare the KGF/KGFR activity between C-COM and NC-COM to determine if they can explain the pathogenesis of cholesteatoma&if they can be used to differentiate between them.the patients with Chronic suppurative otitis media and of both sexes divided into two groups:
Group (1): Consists of 40 patients with cholesteatoma.
Group (2): Consists of 20 patients with non cholesteatoma
The epithelium and granulation tissues were harvested during surgery from all patients from the site of cholesteatoma whereas in the NC-COM group, the epithelium was harvested from the edge of the perforated eardrum and the granulation tissue underneath the epithelium.These specimens were exposed to histopathplogical preparation and examination for the prescence of Keratinocyte growth factor and its receptors.
We found that Keratinocyte growth factor and its receptors are positive In one case only of the non cholesteatoma cases (5%)&negative in 19 cases (95%). where it is positive in 36 cases of the cholesteatoma cases (90%) &negative in four cases(10%).Results were considered significant (s) as student T test P value was |
