Key points:

1 Introduction

During the embryological development, in the fourth week of gestation, six pairs of arches, clefts and pouches form the branchial or pharyngeal apparatus. Every arch consists of a cartilaginous element, muscular component, a corresponding branch of the aortic arch and a cranial nerve. These components later form various structures in the head and neck and due to non-fusion or subinvolution can result in branchial cleft anomalies (BCA).[1, 2] These BCA can occur as sinuses, fistulas or cysts and are present at birth, although maybe symptomatic until later in adulthood. [2, 3] BCA comprise about 20% of congenital lesions in children and arise from the first, second, third or fourth pharyngeal cleft [2]
Whereas first branchial cleft anomalies can be divided into Work type I (preauricular and lateral to the facial nerve) and Work type II (mandibular angle/submandibular and medial/or lateral to the facial nerve), third branchial anomalies present in the middle and lower third of the sternocleidomastoid muscle (SCM). The fourth BCA are extremely rare (1%) and normally present in the middle portion of the SCM.[2]
BCA arising from the second pharyngeal cleft are the most common and represent 40-95%. [2, 4] They are usually located in the lateral neck anterior and medial to the SCM and can have contact to the ipsilateral pharyngeal, explicitly the tonsillar region. [2, 4, 5] The majority of BCA present as cysts between the age of 20-40, in younger age (<5 years) sinuses and fistulas are more common.[4]