European Review for Medical and Pharmacological Sciences 1999; 3: 175-178 Chronic : histopathological changes A post mortem study on temporal bones

F. SALVINELLI, M. TRIVELLI, F. GRECO, F.H. LINTHICUM JR*

Institute of Otolaryngology, “Campus Bio-Medico” University - Rome (Italy) *Department of Histopathology, “House Institute” - Los Angeles, CA (USA)

Abstract. – The temporal bones of 4 Materials and Methods deceased individuals, with concomitant chronic otitis media are studied. The various histopathological changes in the We have studied the histopathological cleft are examined: suppuration, polyps, changes in temporal bones of 4 deceased in- granulation tissue. The possibilities of spon- dividuals, with concomitant chronic OM. taneous healing of a perforated TM and the These patients were donors and agreed indications of surgical treatment are dis- during their life to donate post mortem their cussed. temporal bones to the House Ear Institute as Key Words: a contribution to a better knowledge of tem- Temporal bone, Middle ear, , Chronic in- poral bone diseases. flammation, Metaplasia, Complications. We have removed the temporal bones in our usual way9.

Introduction Results

Otitis media (OM) is an infection localized Clinical features in the middle ear: mastoid, middle ear cavity, The , while often indolent, . The classification of OM in- may at times give rise to serious complica- cludes: tions and even cause death. The that is a constant concomitant also con- tributes to the immense socio-economic problem. Chronic OM sometimes, but not al- • OM with effusion1-3, without perforation ways, follows an attack of the acute disease. of the tympanic membrane (TM)4-6, due The major feature is discharge from the mid- to an increase of fluid in the middle ear dle ear. Sometimes polyps may occlude the cavity, mainly for eustachian tube dis- external auditory meatus. The TM is usually function . perforated in the pars tensa. • OM without effusion, which is the simple inflammation of the TM, that can evolve Gross appearances towards an infection7,8. There has been little study of the gross ap- pearances of chronic OM, except at surgery The two conditions may be predisposing when the examination of the middle ear cleft agents to a perforation of the TM. is limited to the operative field. With the use This is a modification of normal anatomy, of the microslicing method a more complete that let the infectious agents enter into the gross examination of the whole middle ear middle ear cavity. The patient has recurrent may be carried out post-mortem. An impor- or chronic inflammation and infection of the tant feature of chronic OM is the variation in middle ear epithelium and surgical therapy is the degree and extent of the inflammation. mandatory. The tubotympanic region is the most fre-

175 F. Salvinelli, F. Greco, M. Trivelli, F.H. Linthicum Jr quently involved and mastoid air cells may al- Microscopic appearances so be affected. Mucopurulent material often The most characteristic feature of the fills the middle ear space in the tubotympanic pathology of chronic OM is the presence of region and may also be seen within mastoid inflammatory granulation tissue (Figure 1). air cells. In the inflamed regions the mucosa This cellular reaction has two components. is thickened and congestion may be severe. On one hand there is the presence of leuco- Granulation tissue formation may be exten- cytes characteristic of chronic inflammation, sive, showing as red thickened areas particu- i.e. lymphocytes, plasma cells and histiocytes. larly on the promontory, in the epitympanum, On the other hand there is granulation tissue, in the round and oval window niches and in constituted by newly formed capillaries and the mastoid. The granulation tissue on the by fibroblasts (Figure 2). Granulation tissue promontory mucosa may be of sufficient formation takes place in the early stages of thickness to protrude through the perforation healing after the inflammatory destruction of in the TM. Such a lesion is the common aural tissue. Chronic inflammatory leucocytes and polyp presenting clinically in the . granulation tissue may be found in the mid- A variable degree of loss of ossicular bone dle ear in chronic OM independently of each may be observed. The most frequently af- other. The two forms of cellular reaction are fected ossicle is the incus, particularly in the seen together in aural polyps (Figure 3). This region of its long process, but dissolution of lesion is frequently subjected to biopsy in the other ossicles may also occur. In post- investigation of cases of chronic OM. The mortem temporal bones with chronic OM, polyp is usually covered by columnar epithe- large surgically produced cavities are some- lium, which is often ciliated. Sometimes the times present in the mastoid region. These epithelium is squamous. This may be pro- are the results of operations to remove in- duced by metaplasia in the middle ear or by fected parts of the mastoid to drain the mid- irritation of the polyp when it reaches the ear dle ear cleft, and they may or may not be ac- canal. The core of the polyp is made up of companied by evidence of other surgical chronic inflammatory granulation tissue. procedures involving the ossicles, depending Groups of keratin squames accompanied by on the severity of the “clearance” of the foreign body type giant cells may be promi- middle ear undertaken by the surgeon. nent in aural polyps, particularly in the pres- Yellow localized areas seen anywhere in the ence of a of the middle ear. middle ear cleft are regions of cholesterol The middle ear cleft is normally lined by a and pearly white patches particu- single layer of cubical or columnar epitheli- larly in the attic are likely to be um, which may bear cilia. Tos and Bak- , which are frequently pre- Pedersen10,11 studied the normal and patho- sent in association with chronic OM. logical middle ear epithelia by a whole mount

Figure 1. Perforation of the tympanic membrane. Near Figure 2. Granulation tissue (white arrow) forming in the malleus handle the squamous epithelium has migrated fibrous tissue in the middle ear. Black arrow indicates around the edge of the tympanic membrane (arrow). ×35 the tympanic membrane epithelium. ×120

176 Chronic otitis media: histopatological changes: A post mortem study on temporal bones

Figure 4. Chronic otitis media with suppuration. Pus Figure 3. Polyp (1) projecting into middle ear space (1) fills the middle ear space between the tympanic containing fluid and pus cells (2). ×115 membrane (2) and the promotory (3). ×120 method, in which the entire mucosa was re- from an early age. This has been ascribed to moved and stained with PAS-Alcian blue. By inflammatory change, but such an interpreta- this method goblet cells appear as oval to tion has been doubted by others who have re- round, sharply demarcated blue structures on garded the sclerosis as primary, perhaps due a pale background. Few goblet cells were to genetic factors13. The appearance of the found in the normal middle ear, but in chron- mastoid in primary arrest of pneumatization ic otitis the numbers were greatly increased is said to be unlike that following OM, in that to a level similar to those in other parts of the in the former the mastoid air cell system is respiratory tract. Unlike other parts of the small and the bone is diffusely sclerotic. respiratory tract, including the cartilaginous portion of the eustachian tube, where tubulo- alveolar glands containing mucous and serous elements are present, the middle ear is nor- Discussion mally devoid of glands. Under conditions of chronic inflammation, however, the middle The chronic modifications of the middle ear epithelium comes to resemble the rest of ear cleft, visible in our histological slides, the respiratory tract by the formation of show the presence of inflammatory granula- glands. They consist usually of a simple tion tissue (Figure 2) with newly formed cap- tubule of mucus-producing cells. Gland for- illaries and fibroblasts, sometime with active mation is particularly active in children with suppuration (Figure 4) sometimes with secretory OM12. Glandular transformation polyps (Figure 3), but always with variable may take place in the mastoid air cells as well degree of metaplasia in the middle ear. In as the main middle ear cavity. The secretion our opinion, the perforation of the TM must derived from the glands is an important com- be closed as soon as possible. In traumatic ponent of the aural discharge in chronic OM perforations, the earlier the closure, the bet- (Figure 4). The mastoid air cells show fibrosis ter the possibilities of success. The delay in and their bony walls are markedly thickened. operation leads to penetration of antigens Cement lines in the lamellar bone are numer- and bacteria, that provoke infection and ous and irregular, often forming a mosaic pat- modifications of the middle ear cleft, with tern. This indicates the recent active deposi- mastoid involvement. The wait and see policy tion and resorption of bone as a result of the is justified in perforation of TM smaller then inflammatory process. The product of these 2 mm diameter, not in bigger perforations. preparative processes in the mastoid is a As visible in Figure 1, in a big perforation, patchy sclerosis with some cystic cavities rep- the squamous epitelium migrates around the resenting distended air cells. The obliteration edge of the TM14. The fibroblast try to spon- of mastoid air cells as a result of chronic otitis taneously close the perforation, but in big is referred to as secondary sclerosis. In some perforations can not do anything but migrate the mastoid air cells lack pneumatization around the edge of the TM, thus forming a

177 F. Salvinelli, F. Greco, M. Trivelli, F.H. Linthicum Jr concentric fibrous layer that impede the nor- 6) JAISINGHANI VJ, PAPARELLA MM, SCHACHERN PA, LE CT. mal healing of the TM. Further more, the Tympanic mambrane/middle ear pathologic corre- lates in chronic otitis media. Laryngoscope 1999; penetration of epitelium in the middle ear 109: 712-716. cleft is a great favoring conditions for the de- veloping of a cholesteatomatous OM, with 7) FORSENI M, HANSSON GK, BAGGER-SJOBACK D, HULTCRANTZ M. Am J Otol 1999; 20: 152-157. possible severe complications, like labirinthi- 8) HURST DS, AMIN K, SEVEUS L, VENGE P. Mast cells tis, sensorineural hearing loss, facial nerve and tryptase in the middle ear of children with oti- palsy, meningitis. tis media with effusion. Int J Pediatr Otorhinolaryngol 1999; 49 (Suppl) 1: S315-19.

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