Branchial Cleft Cyst.

Branchial cleft cyst, sinuses, and fistulae are among the most commonly encountered congenital anomalies in pediatric otolaryngic practice. They can present difficulty in diagnosis and surgical management. Here, I report a case of 14-year-old boy who presented with asymptomatic, congenital swelling located just below the jawline in the lateral part of the neck. The lesion was excised surgically. Histopathology showed the cyst lined by squamous as well as columnar ciliated epithelium, which was a characteristic finding of branchial cleft cyst. The aim of presenting this case is its rarity.

What was known?

Branchial cleft cyst is most frequently identified along the anterior border of sternocleidomastoid muscle and adjacent to the muscle.

Introduction

Branchial cleft cyst is a rare disease of the head and neck. Because of its rarity, it is often misdiagnosed. Although present at birth, many cases do not become evident until later in childhood or adolescence, with an initial clinical presentation in adulthood being encountered rarely.[1] Branchial anomalies comprise approximately 20% of pediatric congenital head and neck lesions.[2] Here, I report a case of branchial cleft cyst situated in a location which corresponds to its origin that is from the second branchial arch.

Case Report

A 14-year-old male presented with swelling located just below the jawline in the lateral part of the neck since birth. There were no associated complaints such as pain, change in voice, or difficulty in breathing. The swelling was not moving with protrusion of tongue or on deglutition. There was no history of discharge during eating or drinking. However, the patient gave a history of some fluid discharge from the lesion occasionally, which could be the mucin present in the cyst or could be due to the infection. On examination, solitary, smooth, well-defined, nontender cystic mass measuring approximately 2 cm × 2 cm was noted just below the jawline in the lateral part of the neck [Figure 1]. Lateral to the cyst, chicken pox scars were seen. On palpation, the swelling was nonpulsatile; local temperature was not elevated; and it was soft and movable with normal overlying skin. The differential diagnosis of solitary neurofibroma or solitary palisaded encapsulated neuroma was considered. He was advised excisional biopsy. While excising, there was a mucinous discharge from the lesion.

Figure 1

A cystic lesion with sinus just below the jaw line in lateral part of the neck. Lateral to the cyst are chicken pox scars

Complete excision of the cyst was done and sent for histopathology. It showed irregular cystic structure in the dermis. The cyst was lined by two different epithelium [Figure 2]. Outer stratified squamous [Figure 3] and inner columnar ciliated epithelium [Figure 4] with peripheral cells being cuboidal. There was mild inflammatory infiltrate of lymphocytes in the stroma. The lining cells were seen to be producing mucin in foci. The features were suggestive of branchial cleft cyst. The histopathology differentiated it from mucus retention cyst as mucus retention cyst shows several spaces within the connective tissue filled with mucinous material, but without an epithelial lining. Thus, clinical as well as histopathological findings confirmed the diagnosis of second branchial cleft cyst.

Figure 2

Schematic diagram cyst wall lined with two different types of epithelium (H & E ×100)

Figure 3

Schematic diagram part of cyst wall lined with squamous epithelium (H & E ×400)

Figure 4

Schematic diagram ciliated columnar epithelium in another part (H & E ×400)

Discussion

A branchial cleft cyst commonly presents as a solitary, painless mass in the neck of a child or young adult. These congenital epithelial cysts also called as benign cervical lymphoepithelial cyst.[3] Branchial anomalies are sometimes bilateral.[45] Girls and boys are equally affected. Familial occurrence has been recorded.[67]

The branchial cleft cyst has disputed origin. There are various theories regarding its origin.

Congenital theory says that the cysts develop from remnants of the embryonic gill apparatus

Lymph node theories: In 1949, King concluded that the cyst arises from cystic changes in parotid epithelium that become entrapped in upper cervical lymph nodes during embryonic life

Branchial theory: A basic understanding of cervical embryology is essential to the discussion of branchial anomalies.[891011] The branchial apparatus develops during the 2nd–6th week of fetal life. At this stage, the neck is shaped like a hollow tube with circumferential ridges, which are termed as branchial arches. Branchial arches develop into the musculoskeletal and vascular components of the head and neck. The thinner regions between the arches are termed clefts (on the outside of fetus) and pouches (on the inside of the fetus) [Figure 5].

Figure 5

Schematic diagram branchial arches with clefts and pouches 12

The first branchial cleft develops into the external auditory canal. The second, third, and fourth branchial clefts merge to form the sinus of His, which normally involutes. If a portion of the branchial cleft fails to involute completely, the entrapped remnant forms an epithelium-lined cyst with or without a sinus tract to the overlying skin.[29] Occasionally, both the branchial pouch and branchial cleft fail to involute and a complete fistula forms between the pharynx and the skin.

Precervical sinus theory: The cyst represents the persistence of vestiges of the cervical sinus.

Types

First branchial cleft cyst:

Type I: Located near external auditory canal, inferior and posterior to the tragus, may be in the parotid gland

Type II: Located at the angle of the mandible and may involve submandibular gland.

True anomalies of the first branchial cleft are uncommon. Skin tags, preauricular cysts, and sinus tracts around the ear are not of branchial origin but occur from abnormal entrapment of epithelium during the merger of the six hillocks of His that form the external pinna. They are purely ectodermal in origin.

Second branchial cleft cyst: Among the branchial cleft malformations, the second cleft lesions account for 95% of the branchial anomalies.[5] They are most frequently identified along the anterior border of sternocleidomastoid muscle and adjacent to the muscle. They present as a cyst, sinus, or fistula or any other combination and are of ectodermal and mesodermal in origin containing squamous epithelium, adnexal structures, or cartilage. Attention is usually drawn to the problem by mucoid drainage or recurrent infection. The cyst contains turbid fluid and, therefore, does not transilluminate. Sinuses present in the first decade of life and cysts in the second decade of life

A third branchial cyst is rare. The cyst may arise from the left side of the neck in close relation to the thyroid gland

Anomaly of the fourth branchial pouch is very rare. It may produce a cyst or a fistula very low in the neck.

On histopathology, it shows cyst with lining epithelia were classified into stratified epithelium without keratinization, columnar epithelium with or without cilia, or a mixture of both. Branchial cleft cysts are usually lined by squamous epithelium in about 90% cases. Eight percentage of them are composed of ciliated columnar epithelium, and 2% show both types of epithelium.[10] Beneath the epithelium, there is usually lymphoid tissue, often with germinal centers and subcapsular lymph sinuses. A branchial cleft cyst is often surrounded by lymphoid tissue. Often there are marked inflammatory changes and the epithelium overlying the lymphoid tissue is attenuated or absent.

In this case, the location of the cyst corresponded to its origin that is from the second branchial arch. The histopathology showed the features of branchial cleft cyst. Hence, the diagnosis of the second branchial cleft cyst was accomplished. To the best of my knowledge, the case of branchial cleft cyst has not yet been reported in Indian Dermatology Literature. In my patient, the histopathology showed both types of epithelium, squamous as well as ciliated columnar epithelium, which is rare to be seen.

Differential diagnosis

The differential diagnosis of branchial cleft cyst includes unilateral lymphadenopathy and could be malignant or tuberculoid, parotid and thyroid tumors, thyroglossal cyst, dermoid cyst, teratoma, cystic hygroma, carotid body tumor, infantile lymphangioma, or neurofibroma. The fluctuant nature of the swelling rules out the solid masses such as tumors involving various tissues in the submandibular region and neck as well as cervical lymphadenopathies. Thyroglossal duct cysts present as a midline neck mass at or below the level of the hyoid bone, and it moves with swallowing. Dermoid cysts occur in the midline and differ in location from the cyst in the present case. All these lesions differ in microscopic features from branchial cleft cyst. Cystic hygroma occurs in the posterior triangle of the neck that is posterior to the sternocleidomastoid muscle.

Treatment

Treatment must be tailored depending on which branchial arch is involved and whether a cyst mass or sinus/fistula tract is present.[9] The only effective treatment is total surgical excision. The lack of treatment puts a patient at risk of infections while incomplete removal might result in recurrence. Surgical excision is the gold standard treatment of lesions of branchial anomalies.[10]

Conclusion

Thus, a rare case of branchial cleft cyst is being presented with the aim that, such cases should be identified and treated adequately. It is uncommon to suspect a lesion of such a type in dermatology, and this often leads to misdiagnosis and improper treatment. Hence, the present case is reported.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

What is new?

But, in this case the cyst was located just below the jawline in the lateral part of neck. Thus, the location of the cyst made this case unusual.