Evaluating Masses in the Neck

Emerg Med 36(9):20-28, 2004

The many possible causes of a neck mass include congenital, infectious, traumatic, neoplastic, toxic, and vascular processes and conditions. Beginning with a scheme that divides the complex anatomy of the neck into three zones and two triangles, the authors present a systematic approach to assessment.

By Carrie H. Vice, MD, and Cherri Hobgood, MD

Diagnosing and treating patients with neck masses is a challenge for primary care physicians. Management of neck masses requires an understanding of the neck's complex anatomy and multiorgan system pathology. Often, making an accurate diagnosis can only be achieved with tests such as computed tomography (CT), magnetic resonance imaging (MRI), or fine-needle aspiration of the mass. It is important to rule out life-threatening conditions such as impending airway compromise, invasion into vascular, neurologic, or gastrointestinal structures, or signs of systemic illness accompanying the mass.

The most important step in the evaluation of neck masses is deciding how quickly a workup needs to be initiated and determining which studies are needed for a complete workup. Patients with suspected life-threatening conditions should be sent for emergent evaluation and treatment. Those patients with more slowly progressing symptoms may be evaluated as an outpatient with proper specialist follow-up.
 

THREE ZONES OF THE NECK

There are two approaches to mapping the anatomy of the neck. The first uses zones; the second, triangles.

Dividing the neck into three zones has long been used for decision-making with penetrating neck trauma. Zone I extends from the cricoid cartilage to the clavicles and sternum. Important structures in this zone are the vertebral and proximal carotid arteries, large thoracic and mediastinal vessels, superior mediastinum, lungs, trachea, esophagus, thoracic duct, and spinal cord.

In patients who have stable vital signs, trauma to this zone requires evaluation by a specialist using angiography, esophagoscopy, and laryngoscopy. Injuries in this zone can be devastating because they can extend into the chest. Conservative management rather than neck exploration is preferred because it is difficult to evaluate these structures surgically. Diagnostic errors may prove fatal with the rapid development of mediastinal infections or vascular compromise.

Zone II encompasses the area between the angle of the mandible and the cricoid cartilage. Important structures in this zone are the carotid and vertebral arteries, jugular veins, larynx, trachea, esophagus, and spinal cord. Injuries in this zone are more clinically apparent and for this reason observation with supportive diagnostic studies is becoming more common. Significant injuries here are seldom occult, and because the structures in this zone are more easily dissected, surgical exploration of this zone is readily undertaken for injury management.

Zone III encompasses the area above the angle of the mandible. In this zone are the distal carotid and vertebral arteries, pharynx, and spinal cord. As with zone I, surgical exploration of this zone is difficult because many of these structures enter the skull base. With this zone, angiography is required for all stable patients.
 

TWO CERVICAL TRIANGLES

The neck can be further divided into triangles, the two most important being the anterior and posterior cervical triangles. The anatomic borders of the anterior cervical triangle are the medial portion of the sternocleidomastoid muscle, the lower border of the mandible, and the midline of the neck. Important structures within this triangle are the carotid arteries and jugular veins, thyroid gland, esophagus, trachea, larynx, and vagus nerve. The posterior cervical triangle's borders are the lateral edge of the sternocleidomastoid muscle, trapezius, and clavicle. Within this region are the subclavian artery and vein, suprascapular artery, and brachial plexus.

Lastly, the neck has several fascial planes. The superficial cervical fascia houses the platysma muscle and superficial blood vessels, lymphatics, fat, and nerves. Infection in this superficial layer does not spread; however, any infection deeper than this layer may dissect the fascial planes and spread to vital contiguous areas such as the mediastinum and thoracic cavity.

For a guide to the significance of anatomic locations in the preliminary differential diagnosis, see the table below.
 

HISTORY AND PHYSICAL EXAMINATION

Important factors to consider during the history-taking are listed in the box below. During the physical examination, a complete external and internal oral examination should be performed in all patients. This should include the floor of the mouth and the nasopharynx. In all patients, the mass should be palpated and its quality assessed. Is it firm and fixed? Or is it mobile and fleshy? Is there surrounding erythema, fluctuance, or the sensation of fluid? Are there multiple lesions?
 

Adjacent organ systems, particularly the respiratory system, should be examined. Overt stridor is indicative of significant airway compromise and a tracheal diameter of less than 10% of normal. Other changes in phonation or respiratory effort should be evaluated in relation to potential airway compromise from the neck mass. The patient's cardiovascular status should be assessed; some tumors, especially those of the paraganglioma class, may excrete vasoactive substances that result in hypertension. In all patients with neck masses, a full neurologic examination should be performed to detect impingement of cranial nerve function or other compromise.
 

CONGENITAL CAUSES OF NECK MASSES

A helpful mnemonic for establishing a differential diagnosis for neck masses is CIT-N-VIT, which stands for congenital, infectious, traumatic, neoplastic, vascular, idiopathic or iatrogenic, and toxic or metabolic causes.

Congenital causes include branchial cleft cysts (BCCs), which develop from the remnants of embryologic branchial clefts and are located anterior to the sternocleidomastoid muscle. About 95% of all BCCs are remnants of the second branchial cleft. These cysts can present at any age and are the most common congenital lesion in adults. They are slowly enlarging masses of the neck formed from the buildup of cellular debris.

Branchial fistulas can also form between the skin and the aerodigestive tract. When this occurs, particles of food can be seen at the opening of the cutaneous portion. These masses are usually painless unless they become secondarily infected. Treatment for branchial cleft cysts is complete excision.

Cystic hygromas develop from a malformation of lymphatic channels. These masses do occur elsewhere in the body, but they are most commonly found in the cervical region. Cystic hygromas usually present in childhood, with 80% to 90% occurring prior to age two. They are soft and painless. Because of their lymphatic origin, many cystic hygromas are discovered after an upper respiratory infection. There is a strong association between cystic hygromas and chromosomal disorders such as Turner's and Down's syndromes. If there is no involvement of surrounding tissue, the prognosis is excellent and resection is usually curative. However, if there is localized tissue invasion, recurrence is common after resection.

Teratomas can present as neck masses. They may occur at any age but are more commonly discovered in childhood. These midline masses are derived from pluripotent embryonic stem cells and contain elements of all three germ layers. When found in infancy, they are usually benign; however, after infancy, more than 50% of teratomas are malignant. Complete surgical resection is required for treatment, and workup for malignant spread is indicated.

Thymic cysts are remnants from the thymic tract and, therefore, are found lateral to the midline, either anterior or deep to the sternocleidomastoid muscle. These are very rare lesions that are usually asymptomatic and have a good prognosis. Thymic tissue can be seen histologically within the walls of the cyst.

Thyroglossal duct cysts (TDCs) are midline masses arising from the descent of the thyroid gland from the base of the tongue to below the cricoid. They usually present in childhood but may be found later in life. These cysts are mobile, especially with swallowing or protrusion of the tongue. They are usually not tender, but when infected they can become painful. If infection does occur, initial treatment is with antibiotics; all TDCs require follow-up for complete surgical excision. If they are left untreated, there is an increased risk of malignant transformation.
 

NECK MASSES CAUSED BY INFECTION

Bacterial abscesses are common causes of neck masses, especially in patients with poor dentition. The most common organisms are group A beta-hemolytic streptococcus, Streptococcus pneumoniae, and Haemophilus influenzae. A potentially fatal complication from bacterial infections involving the neck and mouth is Ludwig's angina. This complication presents as brawny edema under the tongue and can rapidly progress to airway compromise. Abscesses need emergent surgical evaluation and antibiotic coverage.

Granulomatous infections can present in the neck from many different causes, such as tuberculosis, syphilis, actinomycosis, and tularemia. These masses need evaluation for possible surgical incision and drainage, which should be performed by a specialist. If granulomatous disease is suspected, referral is indicated. Often, excisional biopsy will be required to obtain specimens for pathology and culture. The results of these tests guide treatment with antituberculosis or antifungal medications.

Infectious lymphadenopathy, especially as a result of the Epstein-Barr virus (mononucleosis), can present with significant neck swelling. Lymphadenopathy from infection tends to be quite painful on palpation; in many cases, multiple nodes can be palpated instead of a single solitary mass. Other common infectious causes of lymphadenopathy are AIDS-related infections, Kawasaki disease, tonsillitis, viral upper respiratory infections, and dental abscesses.

Necrotizing fasciitis can also present in the neck, where it is often of an odontogenic origin. Patients with necrotizing fasciitis commonly have a condition such as diabetes mellitus, vascular disease, alcohol abuse, or cirrhosis that leads to a compromised immune system. These patients tend to be very sick at presentation and need surgical evaluation for extensive debridement as well as broad-spectrum antibiotics.
 

OTHER CAUSES OF NECK MASSES

As noted above, neck masses may also result from traumatic, neoplastic, vascular, idiopathic or iatrogenic, and toxic or metabolic causes. There are also various miscellaneous causes of neck masses.

Traumatic causes. Penetrating traumas should be evaluated systematically. Again, an injury in zone II lends itself to local exploration because of the accessibility of its anatomical contents. Injuries in zones I and III may need further invasive testing because their contents enter the thoracic cavity and the skull, respectively. Blunt trauma can cause significant soft tissue swelling and edema, which can compromise other structures, most importantly the airway. Often, blunt trauma will need to be evaluated with a CT scan.

Neoplastic causes. These masses tend to develop over months to years and are typically painless unless there has been significant invasion into surrounding tissue. Benign masses of the neck include lipomas, fibromas, and hemangiomas. Malignant tumors of the neck include squamous cell of the pharynx, larynx, or oral cavity, metastatic disease to the cervical nodes, thyroid cancers, melanoma, lymphoma, carotid body tumors, and salivary gland tumors.

All neck masses can compromise the airway, but neoplastic processes are especially susceptible to this complication. The presence of stridor and a neck mass should prompt direct fiberoptic laryngoscopy prior to any imaging study such as a CT scan.

Vascular causes. Neck masses can develop from vascular aneurysms, dissections, or malformations. Carotid blowout can be caused by postoperative complications, aggressive infectious etiologies, invasive head and neck tumors, or radiation therapy. Unlike masses resulting from neoplastic or congenital causes, vascular masses tend to develop rapidly over minutes to hours and may be pulsatile.

Idiopathic and iatrogenic causes. Postoperative complications with carotid blowout, as noted above, may be a cause of neck masses. Idiopathic etiologies would be a diagnosis of exclusion.

Toxic and metabolic causes. Several thyroid conditions, such as hyperthyroidism and hypothyroidism, can cause toxic or metabolic derangements that may present as neck masses, including hot and cold nodules, goiters, and inflammatory thyroiditis.

Miscellaneous causes. Masses involving the submandibular gland may be caused by sialolithiasis, sialadenitis, tumors, or abscesses. Muscular sources of masses in the neck include myositis and torticollis. The differential for lesions of the parotid gland includes parotitis, malignant and benign tumors, and Sjögren's syndrome.
 

DIAGNOSTIC TESTING

Although some laboratory values can be helpful in the workup of neck masses, they are rarely of significant diagnostic value. Complete blood counts may suggest a neoplastic source, blood loss from a vascular source, or an elevated white blood cell count from an infectious source. Coagulation factors are important to obtain if a vascular cause is suspected, and thyroid function studies can indicate hyperthyroidism or hypothyroidism.

Plain radiographs can sometimes show soft tissue swelling or foreign bodies, but they cannot demonstrate how surrounding nerve, vascular, or airway structures are being affected. Because of their lack of sensitivity and specificity, x-rays are rarely justified. Computed tomography with intravenous contrast is most often indicated, especially in the acute setting, because it is quick and provides accurate information regarding surrounding structures. Magnetic resonance imaging can be useful in evaluating masses that are close to the skull base or in patients for whom CT is contraindicated, such as those with a contrast dye allergy or an elevated creatinine level from renal failure. However, an MRI is lengthy and costly and should not be done on patients with possible airway compromise or other immediately life-threatening conditions.

Ultrasound can be useful in determining if a mass is solid or cystic and in obtaining a biopsy of the lesion. It can also be used with patients who have contraindications to CT or in facilities where CT and MRI are unavailable.

Another diagnostic modality that can be helpful in the diagnosis of a palpable neck mass is fine- or thin-needle aspiration biopsy. This technique is simple to perform and has few contraindications. In many institutions, the procedure is performed by a pathologist or otolaryngologist, but with training the sample acquisition phase may be performed in the general office setting. A fine needle is introduced into the mass, cells are aspirated, and a cytological diagnosis is rendered by a pathologist. The procedure has a 95% diagnostic accuracy for all head and neck masses and should be used as a first-line diagnostic test for palpable masses that are not obvious abscesses. While there are no absolute contraindications to the procedure, most clinicians are uncomfortable performing fine-needle aspiration biopsy on pulsatile neck masses.
 

TREATMENT OPTIONS

Treatment of neck masses depends on the diagnosis. If there is a possibility of an infectious cause, antibiotics that cover both gram-positive and anaerobic organisms are indicated. Incision and drainage of neck masses is not indicated and in many cases is contraindicated. With certain congenital lesions, this procedure can lead to the formation of a cutaneous track, and with neoplastic lesions it can lead to seeding of the cancer along the needle track. In addition, masses in the neck most often need complete resection of the cyst or abscess wall to prevent recurrence. Masses that are considered in need of drainage or excision are best managed by an otolaryngologist after a thorough workup.

If the diagnosis is unsettled, the patient should have further imaging or diagnostic testing and should be referred to an otolaryngologist. If there is any question of airway compromise, rapidly progressing lesions, severe infections, change in voice, or trauma, an evaluation should be initiated immediately with prompt ear, nose, and throat assessment.

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