White mass in the middle ear.
Different pathologic and nonpathologic conditions can result in the formation of a mass or a mass-like lesion behind the tympanic membrane. The differential diagnosis of a white mass includes a congenital or acquired cholesteatoma, middle ear tympanosclerosis, a cartilage graft, an osteoma of the ossicular chain, and a foreign body (e.g., Silastic). The history and physical examination often suggest the diagnosis.
In the case of a cholesteatoma, the status of the middle ear and tympanic membrane are important in determining its type and origin. Congenital cholesteatoma presents in children as a white mass behind an intact tympanic membrane. Early in the process, the tympanic membrane remains intact while a whitish, pearl-like mass ("pearl") is typically seen in the anterosuperior or posterosuperior quadrant. Primary acquired cholesteatoma originates from an attic retraction pocket and spreads to involve the posterior epitympanum, posterior mesotympanum and, less frequently, the anterior mesotympanum. In advanced cases of both congenital and acquired cholesteatoma, the integrity of the middle ear and tympanic membrane is affected, and distinguishing between primary acquired and congenital cholesteatoma becomes difficult. A white or epidermal inclusion cyst can be seen underneath an intact drum. This often results from iatrogenic introduction of squamous epithelium into the middle ear.
In tyrnpanosclerosis, a hyaline degeneration of fibrous tissue in the ear may involve the tympanic membrane or the middle ear mucosa. A history of recurrent or chronic otitis is usually noted. A calcific plaque often respects the periphery of the eardrum or its remnant. A history of progressive conductive hearing loss is usually present.
Cartilage used during reconstruction may be seen as a white mass underneath the tympanic membrane. Although such a finding is evident to an experienced physician, a novice may misidentify it as a pearl or a recurrent middle ear cholesteatoma. Morphologic characteristics, squared edges, and location help differentiate cartilage from a residual cholesteatoma or a cholesteatomatous pearl. Careful palpation with an otomicroscope can be helpful in certain cases.
We evaluated a patient with a white mass (figure) who had previously undergone a right-side canal-wall-up tympanomastoidectomy for chronic otitis media. Ossicular reconstruction had been undertaken with placement of tragal cartilage on top of a titanium partial ossicular reconstruction prosthesis (PORP). The graft had been placed to prevent extrusion of the PORP. The result was a reduction of the air-bone gap of 20 dB and a mean pure-tone average of 16 dB.
Postoperative hearing results are usually better with a PORP than with a TORP (total ossicular chain reconstruction prosthesis).
Brackmann DE, Sheehy JL, Luxford WM. TORPs and PORPs in tympanoplasty: A review of 1042 operations. Otolaryngol Head Neck Surg 1984;92(1):32-7.
Gerber MJ, Mason JC, Lambert PR. Hearing results after primary cartilage tympanoplasty. Laryngoscope 2000;110(12):1994-9.
Maroun T. Semaan, MD; Jose N. Fayad, MD
From the House Ear Clinic, Los Angeles.