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
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
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).
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
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
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.