Laboratory Studies
No specific laboratory investigations need to be obtained in the workup of a branchial cleft cyst.
Imaging Studies
A sinogram may be obtained. If a sinus tract exists, radiopaque dye can be injected to delineate the course and to examine the size of the cyst.
Ultrasonography helps to delineate the cystic nature of these lesions. [11, 12]
A contrast-enhanced CT scan shows a cystic and enhancing mass in the neck. It may aid preoperative planning and identify compromise of local structures. Note the images below.
First branchial cleft cyst, type II. Contrast-enhanced axial computed tomography scan at the level of the hyoid bone reveals an ill-defined, nonenhancing, water attenuation mass (m) posterior to the right submandibular gland (g).
Second branchial cleft cyst. Contrast-enhanced axial computed tomography scan at the level of the hyoid bone reveals a large, well-defined, nonenhancing, water attenuation mass (m) on the anterior border of the left sternocleidomastoid muscle(s).
MRI allows for finer resolution during preoperative planning. The wall may be enhancing on gadolinium scans. [11]
Other Tests
No other investigations are needed beyond routine preoperative workup.
Procedures
Fine-needle aspiration may be helpful to distinguish branchial cleft cysts from malignant neck masses. [13] Fine-needle aspiration and culture may help guide antibiotic therapy for infected cysts.
Histologic Findings
Most branchial cleft cysts are lined with stratified squamous epithelium with keratinous debris within the cyst. In a small number, the cyst is lined with respiratory (ciliated columnar) epithelium. Lymphoid tissue is often present outside the epithelial lining. Germinal center formation may be seen in the lymphoid component, but true lymph node architecture is not seen. In infected or ruptured lesions, inflammatory cells are seen within the cyst cavity or the surrounding stroma.
-
First branchial cleft cyst, type II. Contrast-enhanced axial computed tomography scan at the level of the hyoid bone reveals an ill-defined, nonenhancing, water attenuation mass (m) posterior to the right submandibular gland (g).
-
Second branchial cleft cyst. Contrast-enhanced axial computed tomography scan at the level of the hyoid bone reveals a large, well-defined, nonenhancing, water attenuation mass (m) on the anterior border of the left sternocleidomastoid muscle(s).
