Bilateral Ear Canal Cholesteatoma with Underlying Type I First Branchial Cleft Anomalies

Abstract

Objectives:

1. To describe a case of bilateral ear canal cholesteatomas in the setting of underlying first branchial cleft cyst anomalies.

2. To review the pathophysiology underlying the development of EAC cholesteatomas from branchial cleft cysts abnormalities.

Methods and Results:

We present a case study of a 61-year-old male presented with chronic right-sided hearing loss and left-sided post-auricular drainage. Clinical evaluation, radiographic work-up, and pathologic analysis confirmed a diagnosis of bilateral ear canal cholesteatoma in the setting of underlying first branchial cleft cyst anomalies. The patient’s clinical course, surgical treatment, and management considerations are discussed here.

Conclusion:

Ear canal cholesteatoma represents a rare clinical disease entity deserving a thorough initial assessment. Careful consideration of underlying diseases that result in chronic inflammation, such as branchial cleft lesions, should be included in the differential diagnosis of idiopathic canal cholesteatoma in the absence prior otologic surgery or trauma.

Introduction:

Cholesteatoma of the external auditory canal (EAC) is a unique clinical entity. Since its initial description by Toynbee[1] in the 19^th century, otolaryngologists have speculated about the pathophysiology of the disease. While the exact mechanism of EAC cholesteatoma formation remains elusive, association with other diagnoses of EAC abnormalities can provide insight into the disease process. Here, we present a case of bilateral EAC cholesteatoma with clinical and pathologic evidence of untreated adjacent first branchial cleft anomalies, which may provide insight into the complex nature of this rare disease.

Case Description:

Clinical Presentation:

A 61-year-old male presented to our institution at our clinic with right-sided hearing loss and left-sided post-auricular drainage in January 2017. He reported a longstanding history of a cyst below his left ear since childhood that accumulated debris and ruptured weekly. He had limited access to healthcare and was unaware of any congenital abnormalities, but reportedly underwent an excision of a left periauricular cyst 2 years prior to presentation. He denied other previous otologic surgery. He did not have a history of diabetes. He endorsed a longstanding history of smoking about 1 pack-per-day, but no other pertinent medical, surgical, or family history was noted.

External evaluation revealed a normal-appearing left pinna with a small pit in the postauricular crease expressing scant purulent/sanguinous drainage. Otoscopic evaluation of the right ear revealed two separate defects of the inferior bony EAC – one immediately adjacent to the annulus and the other near the bony cartilaginous junction. The left EAC had a similar appearance with two bony inferior defects; the medial defect contained squamous debris, and the lateral had purulent drainage. Bilateral tympanic membranes appeared normal, with a clear effusion present in the right middle ear. Preoperative endoscopic evaluation of the EACs is shown in Figure 1A and 1B. A 512-Hz tuning fork exam demonstrated a right-lateralizing Weber with a positive Rinne on the right.

Figure 1:

Preoperative external auditory canal (EAC) endoscopy, left (A) and right (B) and intraoperative views of the external fistula tracts, left (C) and right (D). EAC cholesteatoma can be seen bilaterally just lateral to the inferior-anterior annulus, with type I first branchial cleft fistulae can be seen lateral to the cholesteatoma site separated from the cholesteatoma by a healthy bridge of tissue (A & B). Surgical exploration revealed significant bony erosion below the granulation tissue in both ears. The fistula tract in the left ear contained purulent drainage (A) that was contiguous with external postauricular drainage. Left fistula tract exiting the preauricular crease posterior to the lobule. Inset shows a more detailed view of this region. The fistula tract was cannulated intraoperatively and determined to tract into the external auditory EAC (C). Intraoperative view of the cannulated right sinus tract. An 0-0 Prolene suture was used to probe the right EAC fistula, which revealed a blind pouch that did not track through to the postauricular skin (D).

Audiometric evaluation showed a moderately-severe to severe mixed hearing loss on the right and a mild to severe sensorineural hearing loss on the left. Speech recognition testing was unable to be completed due to the language barrier. A Type B tympanogram with normal EAC volume was noted in the right ear, while a Type C tracing was recorded in the left ear.

Computerized tomography (CT) scan of the bilateral temporal bones revealed bilateral bony erosive changes of the inferior EACs with associated tissue calcification. Diagnostic impression was consistent with probable bilateral EAC cholesteatomas. Representative coronal slices are illustrated in Figure 2.

Figure 2:

Preoperative non-contrasted CT scan of the temporal bones, coronal views. Right ear with bony erosion of the lateral external auditory canal (EAC) with overlying soft tissue debris (A) and left ear with soft-tissue debris in the EAC (B).

Surgical Intervention:

The patient initially underwent left-sided canalplasty, excision of EAC cholesteatoma, with excision of a first branchial cleft cyst. Subsequent right-sided canalplasty, meatoplasty, and excision of EAC cholesteatoma and branchial cleft sinus followed 4 months later. During the first surgery, the presence of both an external fistulous tract behind the pinna (Figure 1C) and an internal tract in the EAC were confirmed. Applying pressure on the external tract resulted in purulent discharge emanating from the lateral defect within the EAC. A modified facelift incision was made, extending inferiorly to the lobule and ending in the preauricular crease. An ellipse was made around the postauricular fistulous tract. Both incisions were carried through the subcutaneous tissue. Skin flaps were then raised over the parotid fascia. Sequential dissection along the tragal cartilage was performed meticulously, and the facial nerve was noted to be medial to the tract. No nerve dissection or parotidectomy was required. During dissection along the tragal cartilage, there was noted to be an irregular area at the bony-cartilaginous junction corresponding to the fistulous tract in the EAC. The tract was dissected out from the post-auricular ellipsed skin down to this area where a second ellipse incision was made around the fistulous tract in the EAC. The tract was then taken out through the parotidectomy incision and removed in its entirety. Bone erosion in the area of the fistula was drilled down with a diamond burr. The cholesteatoma was completely excised, and nonviable bone was removed. Pathologic evaluation of the submitted specimens showed the medially-situated cholesteatoma (Figure 3A) while the lateral fistulous tract was consistent with a branchial fistula (Figure 3B).

Figure 3:

Selected slides from pathologic evaluation of submitted specimens. Upper show specimens from the initial surgery on the right ear, with keratinized squamous epithelium and the underlying granulation tissue representing the usual findings in a classic cholesteatoma (A), and squamous lined fistulous tract mucosa with chronic inflammation, fibrosis and focal granulation tissue formation (B). Submitted specimens from the second procedure are shown in the lower panels with the medially situated cholesteatoma keratin eroding the underlying bone of the external canal (C), and the laterally situated specimen with squamous lined sinus tract extending from the first branchial cleft cyst (D).

The second surgery was carried out via a postauricular approach with an anterior-based Palva-like flap. The bony erosion underlying the medial keratin debris along the annulus required wide saucerization of the inferior EAC with a diamond burr. A tympanomeatal flap was elevated to verify no extension of disease into the middle ear space and to ensure complete removal of cholesteatoma. Normal bone existed between this defect and the more lateral defect. The lateral defect at the bony-cartilaginous junction contained a sinus tract, which was cannulated with an 0-0 Prolene suture to follow its extent, revealing a blind pouch. Bone was drilled away until the area was well-saucerized and remaining soft tissue was excised. Figure 1D shows an intraoperative view of the blind pouch in the lateral EAC. Pathologic evaluation of the submitted specimens from the second procedure showed findings consistent with medially-situated cholesteatoma (Figure 3C) and lateral branchial cleft cyst (Figure 3D). Postoperative course was uneventful without recurrence as of most recent follow-up at >12 months following surgery.

Discussion:

The branchial arches develop in utero during the 4^th to 5^th week of gestation, with defects resulting from incomplete fusion of the cleft or incomplete division of the tube[2,3]. First branchial cleft anomalies account for fewer than 10% of all branchial cleft defects[2,3]. The Work classification system[4] divides the anomalies into two groups: Type 1 defects, which are characterized by exclusively ectodermal origin, are typically located superficially to the facial nerve, and commonly terminate at the bony-cartilaginous junction; and Type II defects, which are both ectodermal and mesodermal in origin, have a variable relationship to the facial nerve, and typically contain a tract ending in the parotid or neck that extends upward to the inferior EAC. Anomalies may be further classified as cysts, sinuses, or fistulas[5] and are known to cause chronic inflammation with or without drainage.

Pathogenesis of cholesteatoma originating in the EAC has been a subject of speculation for many years. In isolated cases[6,7], the presence of a blind pouch or tract has led some to postulate the origination of idiopathic cholesteatoma from entrapment of epithelial nests resulting from abnormal first branchial pouch development[8]. Secondary disease is thought to arise as a post-obstructive or post-traumatic process. Obstruction from EAC stenosis or atresia[9,10], osteoma, foreign bodies, and other lesions has led to the development of cholesteatoma in some cases; however, most commonly secondary disease is seen following iatrogenically entrapped desquamating epithelial tissue[11,12].

The case presented here is of clinical interest for several reasons. From our review of the literature to date, this is the first reported case of synchronous, bilateral EAC cholesteatomas presenting in the context of bilateral branchial cleft anomalies. Furthermore, branchial cleft anomalies are typically diagnosed in pediatric patients, but was delayed in this case due to limited access to healthcare, thus allowing us to observe the natural progress of the disease. Although only a single case, it demonstrates the natural history of first arch anomalies, and may help to understand the pathogenesis of EAC cholesteatoma. The non-contiguous nature of the keratin debris-containing lesions highlights the complexity underlying the etiology of EAC cholesteatoma and may reflect contribution of both entrapment of epithelial nests during aberrant development, as well as a chronic post-obstructive inflammatory mechanism to the progression of disease.

Conclusion:

Canal cholesteatoma often presents in the setting of previous otologic surgery, though chronic untreated inflammation is known to cause EAC cholesteatoma in some cases. Here we present the first reported case of synchronous bilateral EAC cholesteatomas in the setting of chronic inflammation due to Type I branchial cleft anomalies. Branchial cleft lesions of the EAC are rare, but they should be included in the differential diagnosis of idiopathic canal cholesteatoma in the absence prior otologic surgery or trauma.