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Type 1 first branchial cleft anomaly: duplication of the external auditory canal.

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An otherwise healthy 16-year-old boy was referred for evaluation of a 12-year history of recurrent right otitis externa manifesting as meatal stenosis, otorrhea, and otalgia. He was initially evaluated by a local otolaryngologist who identified a large obstructing "cyst" in the proximal external auditory canal (EAC). The patient subsequently underwent incision and drainage under general anesthesia. Despite decompression, he had recurrence of his symptoms only 1 month after surgery, and a magnetic resonance imaging (MRI) study with gadolinium demonstrated a peripherally enhancing, 6-mm, complex cystic structure involving the posteroinferior external auditory canal just lateral to the osseocartilaginous junction (figure 1).

The patient presented to the Mayo Clinic 2 months later, and on examination his right EAC was found to be stenotic compared to his left, and there was a well-formed sinus opening seen in the proximal EAC at the 6 o'clock position (figure 2). A preliminary diagnosis of a first branchial cleft anomaly (FBCA) was made, and a temporal bone computed tomography (CT) study was obtained to determine the extent of the lesion and its relationship to the facial nerve (figure 3).

The patient subsequently underwent complete excision of the sinus tract under general anesthesia, with a combination of endaural and postauricular dissection. Copious amounts of thick, dark cerumen and keratinous debris were expressed from the sinus tract when postauricular pressure was applied (figure 4). Final pathology was consistent with an FBCA, demonstrating a cystic structure with stratified squamous epithelial lining and keratinous debris within the sinus tract.

FBCAs comprise less than 10% of all branchial cleft defects. (1-3) They result from incomplete closure of the ectodermal portion of the first branchial cleft, development of a cyst, sinus, or fistula depends on the degree of closure. Cysts are twice as common as fistulae and sinuses combined. (4) Work developed a two-category classification system proposing that type 1 FBCAs comprise ectodermally lined cysts and are EAC reduplication phenomena, while type 2 FBCAs are ecto- and mesodermally derived and extend well beyond the periauricular region to the angle of the mandible, often involving the parapharyngeal space. (5)

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FBCAs may manifest with a variety of complaints depending on their location and size. Approximately 50% of patients present with preauricular swelling above the hyoid bone, while fewer than 25% of patients have isolated drainage from the ear canal. (3) Owing to FBCAs' variable presentation and lack of other associated facial malformations, patients undergo on average 2 to 3 incision and drainage procedures over a span of 3 to 4 years before the correct diagnosis is reached. (3)

Most anomalous tracts lie superficial to the facial nerve and are extraparotid. (4) The tract is more likely to course deep to the facial nerve in cases presenting before 6 months of age, in cases of fistulae rather than sinuses, and in sinuses in which the external opening is located outside the EAC. (1) Because of their potential convoluted and inconsistent relationship with the facial nerve, preoperative imaging, consent for possible parotidectomy, and careful dissection are critical to favorable outcomes; complete local excision of the tract in continuity with adjacent cartilage is curative.

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Imaging is critical to both the initial diagnosis and surgical planning. CT, MRI, and ultrasonographic studies have been described; however, CT remains the preferred diagnostic test. (4,6) The clinicoradiographic differential diagnosis of FBCAs includes benign lymphoepithelial cysts, venolymphatic malformations, primary parotid neoplasms, and suppurative adenopathy or abscess. The most common CT appearance includes either a thin-rimmed unilocular or elongated multilocular, cystic, low-density lesion in the periauricular vicinity; increased wall enhancement is less common and is usually associated with an active infection. (4,6) MRI may be complementary to CT to better evaluate small lesions and those associated with sinus tracts. MRI typically demonstrates hypointense T1- and hyperintense T2-weighted sequences with unilocular or multilocular cysts. There is typically no peripheral wall gadolinium enhancement with FBCAs unless they are concurrently infected. (6)

References

(1.) D'Souza AR, Uppal HS, De R, Zeitoun H. Updating concepts of first branchial cleft defects: A literature review. Int J Pediatr Otorhinolaryngol 2002;62(2):103-9.

(2.) Olsen KD, Maragos NE, Weiland LH. First branchial cleft anomalies. Laryngoscope 1980;90(3):423-36.

(3.) Triglia JM, Nicollas R, Ducroz V, et al. First branchial cleft anomalies: A study of 39 cases and a review of the literature. Arch Otolaryngol Head Neck Surg 1998;124(3):291-5.

(4.) Harnsberger HR, Mancuso AA, Muraki AS, et al. Branchial cleft anomalies and their mimics: Computed tomographic evaluation. Radiology 1984;152(3):739-48.

(5.) Work WP. Newer concepts of first branchial cleft defects. Laryngoscope 1972;82(9):1581-93.

(6.) Mukherji SK, Tart RP, Slattery WH, et al. Evaluation of first branchial anomalies by CT and MR. J Comput Assist Tomogr 1993; 17(4):576-81.

Matthew L. Carlson, MD; David J. Archibald, MD; Shelagh A. Cofer, MD

From the Department of Otorhinolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minn.
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Title Annotation:PEDIATRIC OTOLARYNGOLOGY CLINIC
Author:Carlson, Matthew L.; Archibald, David J.; Cofer, Shelagh A.
Publication:Ear, Nose and Throat Journal
Article Type:Case study
Geographic Code:1USA
Date:Jul 1, 2011
Words:824
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