Download Differential diagnosis of Neck masses A mass in the neck is a

Differential diagnosis of Neck masses
A mass in the neck is a common finding that present in patients of all age groups. The
differential diagnosis may be extremely wide.
There are 3 main categories: inflammatory, congenital and neoplastic which are different
in their distribution according to the age.
The congenital and inflammatory masses are more common in children and adults below
40 years while a mass in an adult above 40 should be considered as neoplastic until proved
otherwise.
Surgical anatomy
It is impossible to understand the assessment, diagnosis or detailed surgical treatment of
any procedure within the neck without understanding the underlying anatomy.
Anatomical divisions:
The neck is divided by the sternomastoid muscle into 2 triangles: anterior and posterior.
The posterior t. is bounded by the trapezius m. posteriorly, middle third of the clavicle
inferiorly and posterior border of the sternomastoid m. anteriorly.
It can be further subdivided by the omohyoid m. into superior occipital t. and lower
subclavian t.
The anterior t. is bounded by the anterior border of sternomastoid m. posteriorly, mandible
superiorly and the midline of the neck anteriorly. It can be further subdivided into 4 smaller
triangles: muscular, carotid, submandibular and submental triangles.
The structures lying deep to the sternomastoid m. are considered within the anterior
triangle.
Fascial neck spaces
Understanding fascial neck layers and spaces is crucial since operative procedures
appear easier, less vascular and are better controlled if they proceed along fascial spaces
rather than through them.
The superficial fascia of the neck is a single layer of fibrofatty tissue lying superficial to
the platysma muscle.
The deep cervical fascia is more extensive and much more important and lies deep to
the platysma m.
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There are 3 layers of the deep cervical fascia:
1- investing layer: invests the whole neck and splits to surround the trapezius m.
posteriorly and sternomastoid anteriorly. It also surrounds the parotid and submandibular
glands and forms the carotid sheath which surrounds both external and internal carotid
arteries, the common carotid artery along with the internal jugular vein and the vagus nerve.
This layer forms the roof of the anterior and posterior triangles.
2- visceral or middle layer: surrounds the pharynx, larynx , esophagus and trachea and
allow these structures to slide upon each others. The pretracheal fascia which surround the
thyroid gland is included in this layer.
3- internal layer: also known prevertebral fascia and surrounds the deep muscles of the
neck i.e. the 3 scalenus mm. , longus capitus and logus colli , erector spinae and levator
scapula m. It forms the floor of the posterior triangle and has important relations with some
important nerves in the neck. The cervical sympathetic trunk lies superficial to prevertebral
f. while the phrenic nerve and brachial plexus lie deep to it.
Head and Neck lymphatics
There are more than 500 LN in the body, about 200 found in the neck.
The lymphatic drainage of the head and neck is divided into superficial and deep systems.
The superficial system
which drains the superficial tissues of the head and neck consists of 2 circles one in the
head and the other is in the neck.
In the head the lymph nodes are situated around the skull base and known as the
occipital, postauricular, parotid and buccal LN.
In the neck are the superficial cervical, anterior jugular, submandibular and submental
LN.
The superficial system receive s drainage from the skin and underlying tissues of the
scalp and face.
The deep system
Consists of :
1- junctional LN : along the internal jugular vein and divided into upper, middle and lower
groups.
2- spinal accessory group: accompany the spinal accessory nerve in the posterior triangle.
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3- visceral nodes: in the midline of the neck and upper mediastinum.
The deeper structures of the head and neck drain either directly into the deep system or
indirectly through the superficial system first then into the deep system.
It is convenient to use the level system to describe the location of LNs in the neck.
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Level 1: submental and submandibular LN.
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Level 2: upper jugular LN.
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Level 3: middle jugular LN.
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Level 4: lower jugular LN.
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Level 5: posterior triangle LNs ( occipital and spinal accessory LNs) .
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Level 6: anterior midline LNs : pretracheal, prelaryngeal and precricoid LNs.
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Level 7: upper anterior mediastinal LNs.
Causes of a mass in the neck
1- Mass in the anterior triangle
a- midline mass
b- lateral mass
2- Mass in the posterior triangle
Mass in the anterior triangle
A- Midline neck mass
Congenital
1- Thyroglossal cyst:
Remnant of the thyroglossal duct through which the thyroid gland descends from the
foramen cecum in the tongue to its usual position in the neck. The duct atrophies but may
persist as thyroglossal cyst.
It usually lies in the midline of the neck closely related to the hyoid bone as painless,
mobile, cystic mass and moves with swallowing and tongue protrusion.
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Treatment : surgical removal of the cyst with the midportion of the hyoid bone (Sistrunk
procedure) to prevent recurrence.
2- Dermoid cyst:
Is an epithelium-lined cavity filled with skin appendages (e.g., hair follicles and
sebaceous glands), more common in the submental region in the neck but might be found in
other sites in the head and neck as the nose and orbit.. It does not move on swallowing or
tongue protrusion.
Treatment: surgical excision.
Acquired
1- Ludwig's angina :
Inflammation of the soft tissues of the floor of the mouth which may extends into the
neck causing midline swelling in the submental region. Mostly due to dental problem and
caused by Streptococcus viridans.
The swelling is tender, hot and associated with fever and trismus.
Treatment : broad spectrum antibiotics with oral hygiene. Incision and drainage rarely
needed.
2- Perichondritis of thyroid cartilage:
Usually follows radiation to the neck or neck trauma.
Clinically: firm, tender swelling over the thyroid cartilage with bad odor. Pseudomonas
is the commonest M.O. isolated
Treatment: antibiotics with steroids . In resistant cases total laryngectomy is indicated.
3- Tumors of the larynx:
Advanced malignant tumors of the larynx may invade the laryngeal cartilage and skin
presenting as a midline neck mass.
4- Thyroid isthmus swelling:
Whether simple, toxic or neoplastic . Presented as a solid or cystic mass and moves up
with swallowing.
5- Lymph node enlargement: lymphadenopathy (LAP)
Submental, prelaryngeal, pretracheal or precricoid LNs. The cause is either
inflammatory or neoplastic.
6- Skin and associated structures:
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A- Boil: Staph.aureus infection of the hair follicle . Present as a hot tender skin nodule
Treatment: drainage with anti-staph. Antibiotics as cloxacillin.
B- Sebaceous cyst :
Due to obstruction of the sebaceous gland duct. Presented as a cystic painless mass with
a characteristic punctum on its surface.
Treatment : surgical excision.
C- Lipoma:
Slowly growing , ill-defined tumor of fat cells. It is non-tender and lobulated mass.
Treatment: surgical excision if symptomatic.
D- Skin tumors:
Benign as keratoacanthoma and naevi . Or malignant as squamous cell carcinoma, basal
cell carcinoma and melanoma.
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