Branchial cleft cyst
| Branchial arch fistula | |
|---|---|
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| Fistulography of a right branchial cleft sinus. | |
| Classification and external resources | |
| Specialty | medical genetics |
| ICD-10 | Q18.0 (ILDS Q18.020) |
| OMIM | 113600 |
| DiseasesDB | 1588 |
| MedlinePlus | 001396 |
| eMedicine | derm/61 radio/107 |
A branchial cleft cyst is a congenital epithelial cyst that arises on the lateral part of the neck usually due to failure of obliteration of the second branchial cleft (or failure of fusion of the second and third branchial arches) in embryonic development. Less commonly, the cysts can develop from the first, third, or fourth clefts.
Most branchial cleft fistulae are asymptomatic, but they may become infected. The cyst, however, usually presents as a smooth, slowly enlarging lateral neck mass that may increase in size after an upper respiratory tract infection.
Branchial cleft cysts are remnants of embryonic development and result from a failure of obliteration of one of the branchial clefts, which are homologous to the structures in fish that develop into gills.
The cyst wall is composed of either squamous or columnar cells with lymphoid infiltrate, often with prominent germinal centers. The cyst may contain granular and keratinaceous cellular debris. Cholesterol crystals may be found in the fluid extracted from a branchial cyst.
Four branchial clefts (also called "grooves") form during the development of a human embryo. The first cleft normally develops into the external auditory canal, but the remaining three arches are obliterated and have no persistent structures in normal development. Persistence or abnormal formation of these four clefts can all result in branchial cleft cysts which may or may not drain via sinus tracts.
Conservative (i.e. no treatment), or surgical . With surgical excision, recurrence is common, usually due to incomplete excision. Often, the tracts of the cyst will pass near important structures, such as the internal jugular vein, carotid artery, or facial nerve, making complete excision impractical.
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