Differential Diagnosis of Neck Masses

Key Points

A thorough history and physical examination are still the cornerstones of the workup for neck mass.
Pediatric neck masses are more often benign; in adults, neck masses should be assumed to be malignant until proven otherwise.
Proximal aerodigestive tract evaluation is essential to neck mass workup.
Computed tomography is still the most cost-effective imaging modality.
Fine-needle aspiration should be attempted prior to obtaining incisional and/or excisional biopsies.
Thyroglossal duct cyst is the most common congenital neck mass in children.
Lymphoma is the most common pediatric primary neck malignancy.
Thyroid nodules are found more frequently in women.
Metastatic squamous cell carcinoma is the most common malignancy in the adult neck.

A comprehensive understanding of the differential diagnosis of the neck mass is integral to the practice of Otolaryngology–Head and Neck Surgery. Neck mass is commonly the only finding in patients with HPV-positive oropharyngeal squamous cell carcinoma (SCC). Because of this, it is critical to understand the various etiologies that cause a neck mass and to initiate workup of these in a timely manner. Often, patients will present from outside providers with significant delays in diagnosis, and it is incumbent on the practicing otolaryngologist to be able to be expeditious and accurate in obtaining the diagnosis. It is important to keep in mind that although neck masses are common in adults and children, the etiology is often considerably different. The goal of this chapter is less to present a list of possible diagnoses, but, instead, to illustrate a safe and effective pathway to obtaining a timely diagnosis as well as organizing a differential in the physician's mind as to what the most likely etiology of the neck mass is. The definitive management of these entities is beyond the scope of this chapter.

History and Physical Examination

Despite significant progress in clinical diagnostic tools, a thorough history and physical examination of the patient remain the mainstay of the workup of a neck mass. A thorough history of present illness is crucial to determine the etiology of a patient's neck mass. Pertinent symptoms such as dysphagia, odynophagia fever, otalgia, weight loss, upper respiratory infection symptoms, hemoptysis, hearing loss, and dyspnea are all findings that will influence the practitioner's decision-making process. Temporal characteristics are important to delineate. Neck masses that fluctuate in size and have been present for a long time are more suggestive of a congenital or inflammatory process, whereas a persistently enlarging lesion that has been present for a shorter period of time is more concerning for malignancy.

The patient's age is also important in the initial assessment. Clinical suspicion for the etiology of a neck mass can usually be stratified in groups according to age. Pediatric patients (aged 0 to 18 years) have a higher likelihood of having a benign lesion, whereas the adult population (age >18 years) has a higher likelihood of harboring a malignancy. The adult population can be further stratified into young adults (age <35 years) and older adults (age >35 years). Younger adults have a higher likelihood of benign neck masses as opposed to older adults, although malignancy should not be excluded. In fact, when thyroid masses are excluded, it has been shown that adults with neck masses have an 80% chance of the mass being malignant. On the basis of this, a neck mass in an adult should be considered malignant until proven otherwise.

Medical and family history is also extremely important. Soliciting information on the patient's immune status, family history of neck masses, and history of irradiation and prior surgery is important in determining the cause of the neck mass. A detailed social history should focus on tobacco and alcohol exposure as well as illegal drug use. Furthermore, it is important to include aspects of the sexual history to further delineate the risk of an HPV etiology.

After a detailed history is performed, a similarly detailed head and neck physical examination should be carried out. Features of the mass should be detailed and include mobility, tenderness, location in the neck (anterior, lateral, or supraclavicular), firmness, fluctuance, erythema, and palpable bruits. As is detailed later in this chapter, such features are helpful in predicting etiology and are frequently encountered, distinguishing characteristics of benign versus malignant processes.

It is essential for the otolaryngologist not to limit the evaluation to the mass itself. Recognizing that a neck mass can be a regional manifestation of a more proximal disease process, a thorough head and aerodigestive examination is warranted. Detailed evaluation of all visible mucosa-lined surfaces should be performed. This can be facilitated with the use of flexible fiberoptic laryngoscopy in addition to standard indirect laryngoscopy techniques. In addition to visual inspection, palpation of suspicious areas should be performed as well. It is important to remember that pathology can reside in the submucosa of the aerodigestive tract, so palpation of the floor of the mouth, oral tongue, buccal mucosa, palate, tonsillar pillars, tonsils, and base of the tongue is crucial. Of equal importance is the understanding that, on occasion, the neck mass is a manifestation of systemic disease. It is of critical importance to not disregard this possibility in the absence of an obvious etiology within the head and neck. The review of systems and past medical history can also help delineate between local and systemic etiologies of the mass.

Anatomy

A thorough understanding of the anatomy of the neck can be especially helpful in understanding the differential diagnosis of a neck mass. Although the specific anatomy of the neck is beyond the scope of this chapter, it is imperative that the practicing otolaryngologists have a clear understanding of the spaces of the neck. Recognizing whether a mass is supraplatysmal versus subplatysmal or in the anterior or lateral neck can aid immensely in the diagnosis and can allow for more appropriate and cost-effective use of diagnostic adjuncts.

Also of significant importance is being able to relay physical examination findings in a systematic and consistent manner. An in-depth understanding of the neck's nodal stations is central to this principle.

Diagnostic Testing

On acquiring a detailed history and information from the physical examination, it is then incumbent on the otolaryngologist to determine the need for additional information. This can be obtained by means of radiologic diagnostics, imaging, and/or cytologic analysis. The next best step in information acquisition should be guided by the practitioner's clinical suspicion after analyzing the details gleaned from the history and physical examination.

Radiology

Although a number of radiologic studies can be utilized to better characterize a neck mass, it is usually not necessary or efficient to order multiple studies for the workup. The practitioner should utilize the information from the history and physical examination to attempt to order the study of highest diagnostic yield. However, this process requires both an understanding of the various strengths of each radiologic study and the ability to focus in on pertinent findings during the history and physical examination. Simple examples include whether the mass is more likely of inflammatory origin or malignant origin, whether surgery is likely to be indicated, or whether adjunct treatments may be necessary that will obviate the use of certain radiologic modalities. It is also of key importance to maintain a cost-effective approach. Furthermore, in the current era, it is important to distinguish between anatomic and functional imaging of the neck, understanding that the incorrect use of various modalities can lead to confusing and incorrect diagnostic workups.

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