The neck

Lump in the neck

The correct diagnosis of a lump in the neck can often be made with a careful history and examination. The clinical signs of size, site, shape, consistency, fixation to skin or deep structures, pulsatility, compressabiliry, transillumination or the presence of a bruit still remain as important as ever.

Branchial cyst

In the fifth week of foetal development four grooves can be seen on each side of the neck. These are the branchial clefts and the intervening bars are the branchial arches. Each arch contains a central cartilage and each cleft is composed of a groove on the outside and a pouch on the inside. The first cleft persists as the external auditory meatus, but the second, third and fourth normally disappear. A branchial cyst develops from the vestigial remnants of the second branchial cleft, is usually lined by squamous epithelium and contains thick turbid fluid full of cholesterol crystals (Fig. 43.54).

The branchial cyst usually presents in the upper neck in early or middle adulthood and is found at the junction of the upper third and middle third of the sternomastoid muscle at irs anterior border. It is a fluctuant swelling which may transilluminate and is often soft in its early stages so that it may be difficult to palpate. If infection occurs it may become markedly erythematous and tender, and on occasions it may be difficult to differentiate from a tuberculous abscess. Ultrasound and fine needle aspiration both aid with diag­nosis, and treatment is by complete excision. This is best undertaken when the lesion is quiescent as attempted exci­sion of an acutely inflammed cyst may convert it into a branchial sinus which may be more troublesome. Although the anterior aspect of the cyst is easy to dissect, it may pass backwards and upwards through the fork of the common carotid artery as far as the pharyngeal constrictors. It passes superficial to the hypoglossal and glossopharyngeal nerves but deep to the posterior belly of the diagastric. The hypoglossal and spinal accessory nerve are encountered in the operative field and must be positively identified to avoid damage. Microscopic examination of these cysts commonly shows a layer of lymphoid tissue suggesting that these cysts may arise as a result of branchial epithelium entrapped within a lymph node.

Branchial fistula

A branchial fistula (Fig. 43.55) may be unilateral or bilateral and are thought to represent a persistent second branchial cleft. Their external orifice is nearly always situated in the lower third of the neck near the anterior border of the sternocleidomastoid, whilst the internal orifice is located on the anterior aspect of the posterior faucial pillar just behind the tonsil. However, the internal aspect of the tract may well end blindly at or close to the lateral pharyngeal wall, con­stituting a sinus rather than a fistula. The tract is lined by ciliated columnar epithelium and as such there may be a small amount of recurrent mucous or mucopurulent discharge on to the neck. The tract follows the same path as a branchial cyst and requires complete excision often by more than one transverse incision in the neck.

Branchogenic carcinoma

It is doubtful whether a primary carcinoma occurs in association with a branchial cyst and it is almost certainly due to cystic degeneration in a lymph node containing a deposit of squamous carcinoma. The primary focus giving rise to the squamous carcinoma may not be apparent, but is usually in the nasopharynx, tonsil, tongue base, piriform fossa or supra­glottic larynx. Full examination, scanning and biopsy of these areas is necessary to exclude the occult primary.

Cystic hygroma (cavernous lymphangioma)

Around the sixth week of embryonic life, the primitive lymph sacs develop in the mesoblast, the principal pair being situated in the neck between the jugular and subclavian veins; these, which correspond to the lymph parts of lower animals, are known as the jugular lymph sacs. Sequestration of a portion of the jugular lymph sac from the lymphatic system accounts for the appearance of these swellings (Fig. 43.56). Cystic hygroma usually manifests itself in the neonate or in early infancy, and occasionally may be present at birth and be so large as to obstruct labour. Swelling usually occurs in the lower third of the neck and as it enlarges it passes upwards towards the ear. Often the posterior triangle of the neck is mainly involved. As a result of the intercommunication of its many compartments, the swelling is soft and partially compressible, it visibly increases in size when the child coughs or cries, but the characteristic that distinguishes it from all other neck swellings is that it is brilliantly translucent. The cheek, axilla, groin and mediastinum are other, although less fre­quent, sites for a cystic hygroma. Cystic hygromas of the neck can on rare occasions be associated with lymphangiomatous lesions of the tongue. The behaviour of cystic hygromas during infancy is so uncertain that it is impossible at that age to predict what will happen. They sometimes expand rapidly and occasionally respiratory difficulty ensues demanding immediate aspiration of much of the cyst’s contents and even, on occasion, a tracheostomy. The lesion may become infected when it becomes inflamed and painful. Spontaneous regression may occur. The cysts are filled with clear lymph and lined by a single layer of epithelium with a mosaic appearance.

Definitive treatment is excision of all of the cyst at an early stage. This requires a meticulous conservative neck dissection with excision of all lymphatic-bearing tissues whilst preserv­ing the normal neurovascular structures if possible. A pre­liminary injection of sclerosing agents is not advisable as it destroys normal tissue planes making the curative surgery more difficult.

Thyroglossal duct cysts

Embryology. The thyroid gland descends early in foetal life from the base of the tongue towards its position in the lower neck with the isthmus lying over the second and third tra­cheal ring. At the time of its descent the hyoid bone has not been formed and the track of the descent of the thyroid gland is variable passing in front, through or behind the eventual position of the hyoid body. Thyroglossal duct cysts represent a persistence of this track and may therefore be found any­where in or adjacent to the midline from the tongue base to the thyroid isthmus. Rarely, a thyroglossal cyst may be the only functioning thyroid tissue in the body.

Clinical features. The cysts almost always arise in the midline but when they are adjacent to the thyroid cartilage they may lie slightly to one side of the midline (Fig. 43.57). Classically, the cyst moves upwards on swallowing and notably with tongue protrusion but this may occur with other midline cysts, such as dermoid cysts, as it merely indicates attachment to the hyoid bone. Thyroglossal cysts may become infected and rupture on to the skin of the neck presenting as a discharging sinus. Whilst they often occur in children they may also present in adults even as late as the sixth or seventh decade of life.

Treatment. Treatment must include excision of the whole thryoglossal tract which involves removal of the body of the hyoid bone and the suprahyoid tract through the tongue base to the vallecula at the site of the primitive foramen caecum together with a core of tissue on either side. This operation is known as Sistrunk’s operation and prevents recurrence, most notably from small side branches of the thyroglossal tract.

Cervical rib and the scalene syndrome

Approximately 0.5 per cent of people have a seventh cervical rib, of which approximately half are unilateral and more commonly found on the right side. The cervical rib may give rise to nerve pressure symptoms and Fig. 43.58 shows the four main varieties of cervical rib. At their exit from the neck, the brachial plexus and subclavian artery pass through a narrow triangle and, if the base of the triangle is raised by the height of one vertebra due to the interposition of a cervical rib, the subclavian artery and the fourth first dorsal nerve are bound to be angulated or compressed. The artery may become constricted with a fusiform dilation of the first 2—4 cm distal to the constriction. Clotting may occur and portions of a mural thrombus may become detached and give rise to an embolus or emboli (Fig. 43.59). Three clinical situations are encountered with cervical ribs, the simplest being the patient presenting with a lump in the lower part of the neck which may be visible, bony hard and fixed. It may cause tenderness in the supraclavicular fossa. A cervical rib with vascular symptoms occurs only when the rib is complete, and pain in the forearm, but in some instances radiating to the upper arm, is the prevailing symptom. The pain is brought on by use of the arm and the pain is accelerated if the arm is in a raised position at the time of exercise. The pain is relieved by rest and is due to ischaemic changes in the muscles of the arm. The hand on the affected side may be colder than the opposite side, may become unduly pale when it is held aloft and may become blue when it is dependent for a time. The radial pulse may be less than on the normal side and sometimes absent. This will depend on the level of collateral circulation. The distal part of the subclavian artery should be auscultated and the systolic bruit will be significant. Numbness of the fingers may occur, followed by ulceration and very occasionally gangrene.

Treatment is by prompt extraperiostal excision of the cervical rib together with any bony prominence from the first rib. It may be advisable to perform sympathetic denervation of the upper limb. True cervical rib with nerve pressure symptoms is probably a rare occurrence as most cases have been found to be related to cervical spondylosis with pressure on the cervical roots in the region of the intervertebral foramina or by carpal tunnel syndrome which may cause wasting of the thenar eminence. Other conditions such as motor neuron disease and syringomyelia may cause similar symptoms. If a cervical rib needs excision it is essential to remove it with its periosteum or it will regenerate. Care must be exercised to avoid damage to the brachial plexus and phrenic nerves.