Branchiogenic

BRANCHIOGENIC (from Greek branchia—gills and genos—origin), originating from the gills, branchial clefts. The term "branchiogenic" is used to designate various congenital developmental abnormalities or acquired diseases if they are related in their origin to the branchial apparatus. In the early embryonic period, 4 parallel grooves of entoderm form on the lateral wall of the pharynx of the embryo between the branchial arches, and opposite them, on the outer surface of the head and neck, 4 grooves of ectoderm (so-called internal and external branchial grooves, pockets). These branchial grooves, or pockets, deepening, turn into rather deep passages, or clefts, but subsequently all disappear with the exception of the upper one, which goes to the construction of the Eustachian tube, the middle ear, and the external auditory canal. Sometimes it may happen that a part of any of the three lower branchial clefts does not undergo normal reduction but persists in the postnatal period. Under such conditions, this remnant of the external or internal branchial groove can be a source of pathological formations, which are called branchiogenic. This includes branchiogenic fistulas and cysts of the neck, and finally, branchiogenic cancers.

A. Abrikosov. A branchiogenic fistula of the neck (branchial fistula, congenital fistula of the neck, fistula colli congenita) represents a product of incorrect development and involution of the branchial clefts (see Gills), when their complete closure is not observed and narrow fistulous passages remain. Branchiogenic fistulas may have either only an internal or only an external opening, or both. A serous-mucous fluid is usually discharged from the opening of a branchiogenic fistula. The external opening, often barely noticeable, usually lies in the space between the hyoid bone and the sternocleidomastoid muscle, at the inner edge of the latter and more often near the sternoclavicular joint (lateral branchiogenic fistula); less often, branchiogenic fistulas lie medially or parasternally and, for the most part, below the hyoid bone. In the opinion of some authors, the origin of medial fistulas of the neck from branchial clefts is not proven; Bramann points to the significance here of the ductus thyreoglossus; indeed, it is sometimes possible to prove the communication of the fistula with the foramen caecum of the tongue. The lumen of the fistula is usually narrow, the length is short. In the depth, the fistulas run, for the most part, in several parallel passages (up to 20). If the opening of the branchiogenic fistula is located high, the fistula runs in the direction of the greater horn of the hyoid bone, between the carotid arteries, to the tonsillar region, where the opening of internal branchiogenic fistulas is often found, or so-called complete branchiogenic fistulas, i.e., opening both into the pharynx and onto the neck. For one or another characterization of a branchiogenic fistula (lateral, medial), it is important to trace its entire direction; sometimes a fistula arises not where it should be; thus, a medial branchiogenic fistula, in case of suppuration and secondary rupture, can give a lateral opening on the neck. The structure of the walls of a branchiogenic fistula is different; its internal entodermal parts are lined with stratified ciliated or squamous non-keratinizing epithelium, under which is located a layer of lymphadenoid tissue with an admixture of mucous (sometimes salivary) glands and smooth musculature. The ectodermal part of the branchiogenic fistula has the usual structure of skin. Branchiogenic fistulas can be primary, i.e., exist from the very beginning as such, or secondary, developing from branchiogenic cysts. Venglovsky pointed to the close relationship of the branchiogenic fistula to the third branchial cleft (specifically to the ductus thymopharyngeus); Kostanecki and Hammar, however, put forward the significance of the second branchial cleft (ductus ectobranchialis II).

The diagnosis of a branchiogenic fistula of the neck in the majority of cases does not present significant difficulties. A branchiogenic fistula can be confused with a fistula as a consequence of trauma or an inflammatory process (tuberculosis, syphilis, actinomycosis). The location of the fistulous opening—the midline for median fistulas and the medial edge of the m. sternocleidomastoideus for lateral fistulas; the character of the fistula mouth—small, sometimes pinpoint, barely allowing the head of a probe to pass; the absence of significant inflammatory changes on the skin around the fistula is a characteristic symptom for a branchiogenic fistula. The discharge of a branchiogenic fistula is also characteristic. In contrast to fistulas of inflammatory origin, which discharge pus (in actinomycosis, containing characteristic granules), branchiogenic fistulas discharge a purely serous or serous-purulent fluid, in which purulent cells are mixed with epithelial ones. An auxiliary method of diagnosis is a microscopic examination of a scraping of the wall of the fistulous passage: the presence of vulgar granulation tissue speaks for an inflammatory character, the presence of epithelial cells—for a branchiogenic fistula. The treatment of a branchiogenic fistula consists in the destruction of the epithelial lining of the fistula. Injections of various caustic liquids (iodine, silver nitrate) proposed for this purpose usually do not provide a lasting cure, because it is not possible to cauterize all the small recesses and passages of the branchiogenic fistula. Only excision of the branchiogenic fistula is radical; leaving a part of it can lead to a recurrence. To obtain an idea of the length of the fistula, its direction, and relations to neighboring tissues, it is recommended to fill it through the mouth with a 20% solution of NaBr and take an X-ray of the fistula. Incomplete short external fistulas are eliminated by simple splitting and removal of the mucous membrane lining them. The operation for a complete branchiogenic fistula begins with the introduction of a probe into its lumen, on which an incision is made around the mouth of the fistula. Following the course of the fistulous canal, the soft tissues over the probe are cut and the fistula is carefully dissected from its bed. Having reached the hyoid bone, it is often necessary to resect a section of the hyoid bone, with which the end of the fistula is tightly fused. Most median fistulas end at the hyoid bone or in the thickness of the latter; in the case of the continuation of the branchiogenic fistula into the depth, into the foramen caecum of the tongue, the peripheral part of the fistula must be resected, having ligated the central part at the root of the tongue with a ligature, the leaving of which (the central part) for the most part does not lead to recurrences. Lateral fistulas are dissected along the course of the large vessels to the hyoid bone, from where, following the course of the fistula into the depth, they pass under the posterior belly of the m. biventeris and dissect its end at the wall of the pharynx. N. Blumenthal. Branchiogenic cancer, a cancerous tumor of the neck that has developed from preserved epithelial remnants of the external or internal branchial grooves of the embryonic period. Branchiogenic cancers arise either directly from these branchial remnants or from branchiogenic cysts and branchiomas. Branchiogenic cancer is usually encountered in adults (40-50 years old); more often in men. The tumor appears in the depth of the tissues of the neck, usually under the m. sternocleidomastoideus, and in its course exhibits signs of a malignant tumor; sometimes it can reach a significant volume. Microscopic examination most often reveals the structure of squamous cell keratinizing or non-keratinizing cancer; in such cases, only the absence of any connection of the tumor with epithelial organs (skin, larynx, esophagus), as well as the absence of cancer in any other place (e.g., in the head region), make it possible to exclude banal squamous cell cancer or its metastasis to a deep lymph node of the neck and to speak of branchiogenic cancer. In rarer cases, the tumor consists of peculiar garland-like strands of polygonal epithelial cells located among the stroma, in which foci of lymphadenoid tissue are observed; such a structure, approaching a branchioma, presents fewer difficulties for the diagnosis of branchiogenic cancer. During the life of the patient, without surgical intervention and microscopic examination, the diagnosis of branchiogenic cancer is very difficult; usually, the tumor is mistaken for a primary neoplasm of the lymph nodes of the neck, for a tuberculous lesion of them, etc. With further growth, the tumor can spread to neighboring regions, reaching upward to the parotid gland and downward to the clavicle; sometimes it even enters the mediastinum. Spreading anteriorly, branchiogenic cancer can compress the larynx and the trachea. Branchiogenic cancers ulcerate late. Treatment consists in the earliest possible removal of the tumor. Branchiogenic cancer has a tendency even in early stages to tightly fuse with surrounding tissues (v. jugularis, a. carotis, n. vagus), as a result of which its removal is often a technically very difficult operation. De Quervain, Küttner, and others proposed large incisions (cross-shaped, Z-shaped, skin-muscle flap), giving a particularly good and spacious access. With extensive adhesions, it is necessary to ligate large vessels of the neck, often to resect a part of the vagus nerve. The results of the operation for branchiogenic cancer are not particularly encouraging: according to Veau's statistics, only in two cases out of 31 operated was a lasting recovery noted.—See also Branchioma.