Branchial cleft cyst.

Second branchial cleft cyst anomalies can occur in two forms or distributions. In infants, a mass can be found at the level of the angle of the mandible. If an associated fistulous tract is present, the opening is identified in the anterior neck just above the clavicle. The second form is found in young adults. Usually trauma or infection produces the initial appearance of a cystic mass at the level of the mandible. In some cases, there is a history of "unsuccessful abscess drainage." [1]

Computed tomography (CT) and magnetic resonance imaging might reveal a unilocular cystic mass in the posterior submandibular space at the level of the mandibular angle. As the mass enlarges, it usually displaces the submandibular gland anteromedially, the sternocleido-mastoid muscle posterolaterally, and the contents of the carotid space posteromedially (figure). The jugulodigastric lymph node is located in the same area as a typical second branchial cleft cyst. As a result, a second branchial cleft cyst can be mistaken for an enlarged suppurative, reactive, or tumor-infiltrated jugulodigastric node. [1]

From the Department of Radiology, Louisiana State University Health Science Center, New Orleans (Dr. Palacios), and the Department of Radiology and Otolaryngology, University of Illinois Medical Center, Chicago (Dr. Valvassori).

Reference

(1.) Harnsberger HR. Cystic masses of the head and neck: Rare lesions with characteristic radiologic features. In: Harnsberger HR. Handbook of Head and Neck Imaging. 2nd ed. St. Louis: Mosby, 1995:199-223.