cyst

A Boy With a Bump Behind the Ear

Bhagwan Das Bang, MD

A 3-year-old African American boy presented with a swelling behind his right ear. The swelling had been first noticed 2 months ago, and it was cystic, nonpainful, and nontender. The results of a systemic physical examination were otherwise normal.

 cyst

What is the probable diagnosis?

A. First branchial cleft cyst

B. Dermoid cyst

C. Epidermoid cyst

D. Lipoma

(Answer and discussion on next page)

Answer: First branchial cleft cyst

The branchial apparatus develops between the second to sixth week of gestation.1 It is divided into 3 parts: the branchial clefts (derived from ectoderm), the branchial arches (from mesoderm), and the branchial pouches (from endoderm). The first branchial cleft develops into the external auditory meatus; therefore, anomalies of the first branchial cleft often involve external ear canal structures.1 The second through fourth clefts form temporary cervical sinuses, which are obliterated by the proliferation of second arch mesenchyme.1 Many authors maintain that a branchial cleft cyst results from incomplete involution of the branchial apparatus. The second branchial cyst is the most common, representing 95% of branchial cysts.2

First branchial cleft cysts are divided into 2 types. Type 1 cysts are located near the external auditory canal, most often inferior and posterior to the tragus.3 Type 2 cysts are associated with the submandibular gland or are found in the anterior triangle of the neck.3

The branchial cleft cyst commonly presents as a solitary, smooth, cystic swelling in child or a young adult. It is benign and painless unless it is infected or has ruptured. These cysts may become tender, enlarged, or inflamed, or they may develop abscesses, especially during periods of infection, due to the lymphoid tissue located beneath the epithelium. Spontaneous rupture of an abscessed branchial cleft cyst can result in a purulent draining sinus to the skin or the pharynx.

cystThe diagnosis of branchial cleft cyst is made primarily by exclusion based on the patient’s medical history and the mass’s clinical manifestations. Subcutaneous dermoid cysts are saclike growths containing structures such as hair, fluid, teeth, or skin glands; they usually present on the face, neck, or scalp, but most commonly on the forehead. Unlike branchial cleft cysts, however, dermoid cysts are present at birth, and they arise in the midline.

Epidermoid cysts are nonpainful, slowly growing lumps that generally are not present at birth. They may be accompanied by the discharge of a foul-smelling, cheesy substance. A lipoma is a benign tumor with a rubbery consistency that is lobulated and most commonly presents as a subcutaneous, slow-growing mass. The areas most commonly affected by lipoma are the neck, back, and proximal extremities.

Computed tomography (CT), ultrasonography, and fine-needle aspiration biopsy can be useful tools in the diagnosis of a first branchial cyst.3,4 Laboratory tests are of not much use in diagnosing the cysts. CT with contrast may be particularly useful in visualizing the full extent of the cyst and delineate its association with adjacent structures. Histology results of the fine-needle aspirate may show squamous cells, polymorphonuclear cells, lymphocytes, and cholesterol crystals.5

Most uncomplicated branchial cleft cysts call for conservative management. Surgical excision is the definitive treatment, and many surgeons believe that the mere presence of the lesion is reason enough for removal, primarily because of its propensity to become infected. A branchial cleft cyst that does become infected should be treated with antibiotics before surgery. The danger of facial nerve injury during surgery and failure to identify the sinus tract communicating with the external ear canal are the main reasons for incomplete excision.6 The facial nerve must be identified and preserved, and the lesion completely excised. Sclerotherapy with picibanil has been reported to be an effective alternative to surgery. After surgical excision of the cyst, recurrence is uncommon.7

References: 

1.Benson MT, Dalen K, Mancuso AA, Kerr HH, Cacciarelli AA, Mafee MF. Congenital anomalies of the branchial apparatus: embryology and pathologic anatomy. Radiographics. 1992;12(5):943-960.

2.Branstetter BF IV. Branchial cleft cysts imaging. Medscape Reference. http://emedicine.medscape.com/article/382803-overview. Updated February 6, 2013. Accessed November 14, 2013.

3.Finn DG, Buchalter IH, Sarti E, Romo T, Chodosh P. First branchial cleft cysts: clinical update. Laryngoscope. 1987;97(2):136-140.

4.Hong C-H. Branchial cleft cyst. Medscape Reference. http://emedicine.
medscape.com/article/1110351-overview. Updated September 19, 2012. Accessed November 14, 2013.

5.Rosa PA, Hirsch DL, Dierks EJ. Congenital neck masses. Oral Maxillofac Surg Clin North Am. 2008;20(3):339-352.

6.Lanisnik B, Didanovic V, Cizmarevic B. First branchial cleft anomaly, a case for misdiagnosis. Wien Klin Wochenschr. 2004;116(suppl 2):72-74.

7.Glosser JW, Pires CA, Feinberg SE. Branchial cleft or cervical lymphoepithelial cysts: etiology and management. J Am Dent Assoc. 2003;134(1):81-86.

Dr Bang is a pediatrician in Opp, Alabama.