Branchioma

BRANCHIOMA (from Greek branchia- gills and oma- a particle added to denote a tumor), a tumor of branchial origin. The term Branchioma designates those cystic tumors of the neck which arise from the remnants of branchial grooves that have not undergone regression and have been preserved. From these remnants, if they are not in communication with the pharynx or the outer surface of the neck, cysts are usually formed; when they have a significant volume and, especially, if they appear as a polycystoma, i.e., are found to consist of many cavities, they are called Branchiomas. Depending on whether the source of the development of the Branchioma is the remnants of the external or internal branchial grooves, the localization and structure of the tumor may be different. In the first case, a movable elastic tumor lies superficially under the skin and consists of cavities containing an atheromatous mass and lined with a multilayered cornifying squamous epithelium (ectodermal Branchioma or branchial dermoid cyst); in the second case, the tumor is located deep in the neck, often under the m. sternocleidomastoideus, and is formed by cavities and fissures filled with serous or mucous fluid, the inner surface of the cavities being covered by a multilayered ciliated columnar epithelium, beneath which is a voluminous layer of lymphoid tissue (entodermal Branchioma). Branchiomas belong, in their course, to benign tumors, but they may transform into carcinomas (see Branchiogenic).