A Type I first branchial cleft cyst masquerading as a parotid tumor.

Branchial cleft anomalies are caused by incomplete regression of the cervical sinus of "His" during the 6(th) and 7(th) weeks of embryologic development. Although congenital in origin, first branchial cleft cysts (FBCCs) can present later in life. FBCCs are rare causes of parotid swellings, accounting for <1% of all the branchial cleft abnormalities. The diagnosis of FBCCs is a clinical challenge; the condition is often overlooked and mismanaged. We report a case of Type 1 FBCC in a 22-year-old female with an asymptomatic 3.5 cm × 2.5 cm sized cystic mass. It was removed completely under the impression of a cystic tumor of the parotid. On histopathology, the cyst had a squamous epithelium-lined wall with lymphoid aggregation which was characteristic of a branchial cleft cyst. A good understanding of the regional anatomy and embryology can lead to an early diagnosis and thereby effective management of FBCC.

INTRODUCTION

First branchial cleft cysts (FBCCs) are extremely rare causes of parotid swellings and comprise less than 1% of all branchial anomalies.[1] They are frequently misdiagnosed due to their rarity and unfamiliar clinical signs and symptoms. We present a case of Type I FBCC masquerading as a parotid tumor.

CASE REPORT

This was a case report of a 22-year-old female with an unremarkable medical and family history who presented to us with a painless swelling in the left parotid region of 2 years duration, examination revealed a well-circumscribed 3 cm × 3 cm swelling in the left parotid region [Figure 1]. The facial nerve function was preserved and there was insignificant cervical lymphadenopathy. A magnetic resonance imaging scan of the parotid region confirmed the nature and extent of the swelling in the left parotid gland [Figure 2]. Aspiration cytology from the cyst revealed an acellular proteinaceous material with occasional squamoid cells, degenerating lymphoid cells and histocytes. The cyst reappeared in a few days time; she was hence taken up for surgery. The intra-operative finding showed the cystic lesion within the substance of the superficial lobe of the parotid gland. A left superficial parotidectomy preserving all the branches of the facial nerve was successfully done, no fistulous tract was identified. The histopathology showed a cystic lesion measuring 3.5 cm × 2.5 cm × 2.5 cm surrounded by normal parotid tissue all around. The cyst was lined by ulcerated stratified squamous epithelium; the cyst wall showed lymphoid tissue with deep seated investigations of the squamous cells, the lumen was filled with necrotic debris, features suggestive of a brachial cleft cyst [Figure 3]. She is disease free and continues to be on follow-up for over 2 years.

Figure 1

(a) Clinical photograph at presentation. (b) Clinical photograph following left superficial parotidectomy

Figure 2

Magnetic resonance imaging scan of the parotid region showing the well-circumscribed 3.5 cm × 2.5 cm cystic lesion in the left parotid region

Figure 3

H and E, ×20 -section shows a cystic lesion measuring 3.5 cm × 2.5 cm × 2.5 cm surrounded by normal parotid tissue all around. The cyst is lined by ulcerated stratified squamous epithelium; the cyst wall showed lymphoid tissue with deep seated investigations of the squamous cells, the lumen was filled with necrotic debris, features suggestive of a brachial cleft cyst

DISCUSSION

Branchial cleft anomalies are caused by incomplete regression of the cervical sinus of “His” during the 6th and 7th weeks of embryologic development. They can be cysts, sinuses or fistulae.[1] Cystic type of anomalies is more common rather than fistula or sinus type. Cystic type can occur clinically from the first to fourth branchial cleft.

The location of a branchial cleft cyst is determined by which branchial cleft failed to obliterate during embryological development, with the second branchial cleft cyst being the most commonly recognized lesion. The common clinical presentation of a first branchial cleft abnormality includes a swelling in the preauricular region (24%), parotid (35%) or cervical region (41%).[2] FBCC are rare causes of parotid swellings, accounting for less than 1% of all the branchial cleft abnormalities. Although congenital in origin, FBCCs can present later in life, a median age of around 18 years. The diagnosis of FBCCs is a clinical challenge; the condition is often overlooked and mismanaged.[2] Branchial cleft cysts are often infected following repeated upper respiratory tract infection and are found as rapidly expanding cystic mass in the neck. A history of multiple incision and drainage procedures for an abscess in the upper neck area is considered by some pathognomonic for FBCC.[2] The differential diagnosis of FBCC in children includes cystic hygroma, venous malformation, hemangioma, reactive lymphadenopathy and ectopic salivary or thyroid tissue; the differential diagnosis in adults should further include a parotid tumor, tuberculosis or malignancies like Hodgkin's disease, lymphoma and sarcoidosis.

The Work's classification[3] of FBCCs is widely quoted, the Type I lesions are cystic, of ectodermal origin and are lined by stratified squamous epithelium. They are generally considered a duplication anomaly of the membranous external auditory canal, sitting antero inferiorly to the earlobe in association with the parotid gland and superficial to the facial nerve. The relationship between FBCC and the facial nerve is quite variable.[4] Type II FBCCs are of both ectodermal and mesodermal origin. The usefulness of the various anatomical classifications is reported to be limited and it is difficult and confusing to correlate them with the clinical presentation.

True branchial cleft cysts are often lined with stratified squamous epithelium or ciliated columnar epithelium because they originate from the ectodermal side of the invagination of the cleft. The presence of lymphoid aggregates in the wall of the lesion and keratin debris is a characteristic finding of branchial cleft cysts. The management of FBCCs is complete surgical excision with preservation of facial nerve and to reconstruct the otological structures if necessary.[567] The variable relationship of the facial nerve with the cyst warrants early identification and complete exposure of the course of the nerve, herein lies the technical challenge of performing a safe and complete excision. A good understanding of the regional anatomy and embryology is therefore imperative; it can lead to an early diagnosis and thereby effective management of FBCCs.