AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Background

To extract oxygen from their environment, fish evolved thin, layered membranes termed gills (branchiae in Latin), which developed from layers of endoderm in the lateral neck. The human fetus has arches of tissue that are similar to those of fish but that develop into various structures in the head and neck rather than into gills. The similarity between piscine and human embryology thus provides the terminology for human head and neck precursors: the branchial apparatus.

Many developmental anomalies of the branchial apparatus have been identified: cysts, fistulas, sinuses, ectopic glands, and malformations of head and neck structures. This article focuses on the most common abnormality of the branchial apparatus, the branchial cleft cyst. References listed at the end of the article further discuss the various branchial anomalies and associated embryology (see References).

Pathophysiology

The pathophysiology of branchial cleft cysts is controversial. Most authors maintain that branchial cleft cysts result from incomplete involution of the branchial apparatus. Others propose that branchial cleft cysts result from ectopic epithelial cells growing along the course of branchial clefts.

Mortality/Morbidity

• Branchial cleft cysts are benign; however, superinfection, mass effect, and surgical complications account for morbidity.
• Recurrence rates of 3-20% are reported.
• The possibility of carcinoma arising in a branchial remnant is controversial; some authors suggest that branchiogenic carcinoma is possible, but metastatic squamous cell carcinoma to regional lymph nodes that masquerade as a branchial cleft cyst is far more common.

Race

No racial predilection has been identified.

Sex

No sexual predilection has been identified.

Age

Branchial cleft cysts are congenital anomalies; however, they are identified most often in the second to fourth decades. Branchial anomalies such as sinuses and fistulas are usually diagnosed during infancy.

Anatomy

A basic understanding of cervical embryology is essential to the discussion of branchial anomalies. The branchial apparatus develops during the second to sixth weeks of fetal life. At this stage, the neck is shaped like a hollow tube with circumferential ridges, which are termed branchial arches. Branchial arches develop into the musculoskeletal and vascular components of the head and neck. (Differentiation of the arches is a fascinating topic that explains much of the unusual anatomy in the head and neck, but it is beyond the scope of this article.)

The thinner regions between the arches are termed clefts (on the outside of the fetus) and pouches (on the inside of the fetus) (see Image 1). Branchial pouches develop into the middle ear, tonsils, thymus, and parathyroid glands.

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 will normally become involuted. When a branchial cleft is not properly involuted, a branchial cleft cyst forms. Occasionally, both the branchial pouch and branchial cleft fail to become involuted, and a complete fistula forms between the pharynx and skin.

First branchial cleft cysts

First branchial cleft cysts are divided into type I and type II. Type I cysts are located near the external auditory canal. Most commonly, they are inferior and posterior to the tragus (base of the ear), but they may also be in the parotid gland or at the angle of the mandible. Type I cysts may be difficult to distinguish from a solid parotid mass on clinical examination. Type II cysts are associated with the submandibular gland or found in the anterior triangle of the neck (see Image 2).

Second branchial cleft cysts

The second branchial cleft accounts for 95% of branchial anomalies. Most frequently, second branchial cleft cysts are identified along the anterior border of the upper third of the sternocleidomastoid muscle and adjacent to the muscle. However, these cysts may present anywhere along the course of a second branchial fistula, which proceeds from the skin of the lateral neck, between the internal and external carotid arteries, and into the palatine tonsil (see Image 3). Therefore, a second branchial cleft cyst is part of the differential diagnosis of a parapharyngeal mass.

Third branchial cleft cysts

Third branchial cleft cysts are rare. A third branchial fistula extends from the same skin location as a second branchial fistula (recall that the clefts merge during development); however, a third branchial fistula courses posterior to the carotid arteries and pierces the thyrohyoid membrane to enter the larynx, terminating on the lateral aspect of the pyriform sinus. Third branchial cleft cysts occur anywhere along that course (eg, inside the larynx), but they are characteristically located deep to the sternocleidomastoid muscle (see Image 4).

Fourth branchial cleft cysts

Fourth branchial cleft cysts are extremely rare. A fourth branchial fistula arises from the lateral neck and parallels the course of the recurrent laryngeal nerve (around the aorta on the left and around the subclavian artery on the right), terminating in the apex of the pyriform sinus; therefore, fourth branchial cleft cysts arise in various locations, including the mediastinum.

Clinical Details

Patients most commonly present with a palpable neck mass. Branchial cleft cysts enlarge and become tender when infected (eg, following an upper respiratory tract illness). Patients also may present with a mass effect such as respiratory compromise.

Complete surgical resection is the treatment of choice and results in a good prognosis. Complications of surgical treatment include recurrence, formation of a persistent fistula, and damage to the cranial nerves. Patients with infected cysts receive a full course of antibiotics before surgery to decrease the risk of recurrence and persistent fistula.

Alternative treatments, such as percutaneous sclerotherapy, are promising but remain unproven.

Preferred Examination

Both computed tomography (CT) scanning and magnetic resonance imaging (MRI) are useful in the evaluation of branchial cleft cysts. The choice of preferred modality depends heavily on regional preferences, with some institutions favoring MRI and others favoring CT scanning. Advocates of MRI believe that this modality more reliably confirms the cystic nature of the mass and more precisely defines the extent of the lesion and its relationship to the surrounding structures. Advocates of CT scanning believe that for most lesions, all the clinically relevant information is available as clearly on CT scan as on MRI, but with preferable cost, availability, and ease of imaging.

MRI is most advantageous for type I first branchial cleft cysts and for parapharyngeal masses that may be second branchial cleft cysts. The relationship of glandular tissue to the mass (eg, fat planes between the parotid gland and a parapharyngeal mass) is important for differential diagnosis and for surgical planning.

Ultrasound is useful in situations where CT scanning and MRI are unavailable. Although ultrasound can confirm the cystic nature of a mass, it does not adequately evaluate the extent and depth of neck lesions.

Limitations of Techniques

Both CT scanning and MRI may be unable to distinguish a branchial cleft cyst from a lymphangioma in children. In adults, metastatic squamous cell carcinoma to cervical nodes may mimic a branchial cleft cyst.

DIFFERENTIALS

Section 3 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Other Problems to be Considered

Metastatic squamous cell carcinoma
Glandular cysts
Lymphadenopathy
Dermoid tumor of the neck
Ranula
Laryngocele
Thyroglossal duct cyst
Lipoma
Hemangioma of soft tissue

CT SCAN

Section 4 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Findings

Contrast-enhanced CT scan reveals a well-defined, nonenhancing mass of fluid attenuation in a characteristic location. The location depends on which branchial cleft is affected.

Type I first branchial cleft cysts appear posterior and inferior to the external auditory canal. Type II first branchial cleft cysts appear near the angle of the mandible or in the anterior triangle of the neck.

Second branchial cleft cysts, by far the most common, appear immediately anterior to the upper third of the sternocleidomastoid muscle.

Third branchial cleft cysts lie beneath or posterior to the sternocleidomastoid muscle, within the posterior triangle of the neck.

Fourth branchial cleft cysts, which are exceedingly rare, may be located in the larynx, in the mediastinum, or along the course of the recurrent laryngeal nerve.

Degree of Confidence

CT scan findings are usually diagnostic for branchial cleft cysts, but differential considerations include lymphangioma (cystic hygroma, lymphatic malformations), glandular cysts, lymph nodes, ranulas, dermoid cysts, laryngoceles, thyroglossal duct cysts, lipomas, hemangiomas (venous malformations), and paragangliomas.

Lymphangiomas (more properly termed "lymphatic malformations") are cystic masses that most often arise in the posterior triangle of the neck; however, these lesions can appear anywhere in the body and can be difficult to distinguish from branchial cleft cysts (see Image 5). Branchial cleft cysts are usually well defined and round, whereas lymphangiomas may be infiltrative. Both lesions are treated with surgical excision. On cross-sectional CT imaging, a branchial cleft cyst can be confused most easily with a lymphangioma.

Glandular cysts, including thymic and parathyroid cysts, are within the spectrum of branchial anomalies. Branchial cleft cysts may involve nearby glandular structures (see Image 6); however, thyroid cysts are more likely to result from degenerated adenomas.

Neoplastic or inflammatory lymphadenopathy can have a clinical and radiographic appearance similar to that of branchial cleft cysts. Cystic metastases (eg, papillary thyroid carcinoma), necrotic metastases (eg, squamous cell carcinoma), and tuberculous lymphadenitis can result in low-attenuating lymph nodes. In patients with acquired immunodeficiency syndrome (AIDS), mycobacterial infections (eg, Mycobacterium avium-intracellulare [MAI] or Mycobacterium avium-intracellulare complex [MAC]) often manifest with cystic cervical nodes. Lymphoma is unlikely to demonstrate cystic degeneration. Positron emission tomography (PET) can be used to distinguish benign masses from malignant masses, but it is notoriously inaccurate in the setting of predominantly-cystic metastases.

Regarding ranulas, lingual salivary gland dilatation may result in a cystic mass extending from the oral cavity through the mylohyoid muscle into the submandibular triangle (ie, plunging ranula). A plunging ranula may mimic a type II first branchial cleft cyst

Dermoid cysts arise in the midline; this feature distinguishes them from branchial cleft cysts. Dermoid cysts generally have low attenuation because of their fat content.

Laryngoceles should be considered in the differential diagnosis of third or fourth branchial cysts arising in the larynx. Both lesions may have thin or imperceptible walls, usually contain simple fluid, and appear on the lateral aspect of the larynx.

Suprahyoid thyroglossal duct cysts lie in the midline. Infrahyoid thyroglossal duct cysts may be off the midline but usually are not as lateral as branchial cleft cysts.

Lipomas have lower attenuation than cysts on CT scans. Liposarcomas of the neck have a variable appearance, but these lesions are rare.

Hemangiomas (venous malformations) often form mixed tumors with lymphangiomas and can appear anywhere in the neck. Hemangiomas show contrast CT scan enhancement, particularly on delayed images; therefore, they can be distinguished from branchial cleft cysts.

The vascularity of paragangliomas makes them easy to distinguish from branchial cleft cysts; however, these entities may be difficult to distinguish clinically.

MRI

Section 5 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Findings

The diagnosis of branchial cleft cysts is based primarily on the location of the lesion (see CT Scan above).

Branchial cleft cysts have high signal intensity on T2-weighted images. On T1-weighted images, the signal intensity is usually low, but prior infection can provoke proteinaceous debris that increases the T1 signal intensity. Uninfected branchial cleft cysts should not enhance on MRI.

Infiltration of surrounding tissue may indicate lymphangioma.

ULTRASOUND

Section 6 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Findings

Ultrasonography may be used to confirm the cystic nature of a neck mass, but it is not commonly used in North America.

ANGIOGRAPHY

Section 7 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Findings

Fluoroscopic fistulography or CT fistulography may be used to delineate the course of a branchial cleft sinus or fistula. This can aid in surgical planning and in predicting potential complications from surgery.

INTERVENTION

Section 8 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Although percutaneous ablation has been considered for branchial cleft cysts, surgery remains the treatment of choice.

Medical/Legal Pitfalls

• Erroneously diagnosing metastatic disease instead of a branchial cleft cyst may result in a more extensive surgery than necessary.
• Erroneously diagnosing a branchial cleft cyst instead of metastatic disease may delay definitive treatment.

MULTIMEDIA

Section 9 of 10  

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

Media file 1:  Coronal cross-section of the right side of the neck in a fetus.
	View Full Size Image
Media type:  Image

Media file 2:  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).
	View Full Size Image
Media type:  CT

Media file 3:  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).
	View Full Size Image
Media type:  CT

Media file 4:  Third branchial cleft cyst. Contrast-enhanced axial computed tomography scan at the level of the thyroid cartilage reveals a large, well-defined, nonenhancing, water attenuation mass (m) deep to the right sternocleidomastoid muscle (s), medially displacing the common carotid artery and internal jugular vein.
	View Full Size Image
Media type:  CT

Media file 5:  Lymphangioma mimicking a type I first branchial cleft cyst. Nonenhanced axial computed tomography scan at the level of the parotid glands reveals an ill-defined water attenuation mass (m) immediately anterior to the left parotid gland (p).
	View Full Size Image
Media type:  CT

Media file 6:  Intraglandular extension of the third branchial cleft cyst. Contrast-enhanced axial computed tomography scan at the level of the cricoid cartilage reveals an ill-defined water-attenuation mass (m) within the right lobe of the thyroid gland. Note the third branchial cleft cyst (c) lateral to the thyroid gland and deep to the sternocleidomastoid muscle(s).
	View Full Size Image
Media type:  CT

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Differentials
• CT SCAN
• Mri
• Ultrasound
• Angiography
• Intervention
• Multimedia
• References

• Benson MT, Dalen K, Mancuso AA. Congenital anomalies of the branchial apparatus: embryology and pathologic anatomy. Radiographics. Sep 1992;12(5):943-60. [Medline].
• Brown RL, Azizkhan RG. Pediatric head and neck lesions. Pediatr Clin North Am. Aug 1998;45(4):889-905. [Medline].
• Chandler JR, Mitchell B. Branchial cleft cysts, sinuses, and fistulas. Otolaryngol Clin North Am. Feb 1981;14(1):175-86. [Medline].
• Gadiparthi S, Lai SY, Branstetter BF 4th. Radiology quiz case 2. Parapharyngeal second branchial cleft cyst. Arch Otolaryngol Head Neck Surg. Sep 2004;130(9):1121, 1124-5.
• Hamilton WJ, Mossman HW. Alimentary and respiratory systems. In: Hamilton WJ, Mossman HW (eds). Human Embryology. 4th ed. London, UK: Macmillan Press;1972:291-376.
• Jereczek-Fossa BA, Casadio C, Jassem J. Branchiogenic carcinoma – conceptual or true clinico-pathological entity?. Cancer Treat Rev. Apr 2005;31(2):106-14.
• Koch BL. Cystic malformations of the neck in children. Pediatr Radiol. May 2005;35(5):463-77.
• Mukherji SK, Fatterpekar G, Castillo M. Imaging of congenital anomalies of the branchial apparatus. Neuroimaging Clin N Am. Feb 2000;10(1):75-93. [Medline].
• Som PM, Smoker WRK, Curtin HD. Congenital lesions. In: Som PM, Curtin HD, eds. Head and Neck Imaging. 4th ed. St. Louis, Mo: Mosby-Year Book;2002:1828-64.
• Som PM, Sacher M, Stollman AL. Common tumors of the parapharyngeal space: refined imaging diagnosis. Radiology. Oct 1988;169(1):81-5. [Medline].
• Tom BM, Rao VM, Guglielmo F. Imaging of the parapharyngeal space: anatomy and pathology. Crit Rev Diagn Imaging. 1991;31(3-4):315-56. [Medline].
• Weichert CW, Presch W. Respiratory system and related structures. Elements of Chordate Anatomy. 3rd ed. New York, NY: McGraw-Hill;1967:131-61.
• Whetstone J, Branstetter BF, Hirsch BE. Fluoroscopic and CT fistulography of the first branchial cleft. AJNR Am J Neuroradiol. Oct 2006;27(9):1817-9.

Article Last Updated: Oct 24, 2006