Evaluating neck masses

Nurse Practitioner, Apr 2000 by Prisco, Michelle Kennedy

ABSTRACT

Neck masses often present a diagnostic challenge to the primary care provider: Etiologies range from benign inflammations to life-threatening malignancies. Categorizing the etiologies into three broad categories is helpful when considering the extensive differential diagnosis for a neck mass: congenital, inflammatory/ infectious, and neoplastic causes. This article discusses the evaluation and subsequent determination of whether a neck mass is significant and warrants further evaluation or is insignificant and may simply be observed. By performing a thorough history and physical examination, primary care providers can narrow the possibilities, differentiate between significant and insignificant neck masses, and select the appropriate treatment.

Most patients with neck masses initially present to their primary care providers. Consequently, primary care providers must be familiar with the evaluation and dif ferential diagnosis of neck masses. By understanding the general anatomical structures, addressing key questions during the history, performing a complete physical examination, and reviewing the differential diagnosis, clinicians will be better able to differentiate between masses that may simply be observed and masses that warrant referral.

Etiology

Neck mass evaluation often presents a challenge to the primary care provider. The etiologies range from benign inflammations to life-threatening malignancies.1 The etiologies can be categorized into three broad categories: congenital, inflammatory/infectious, and neoplastic causes. The differential diagnosis for a neck mass is extensive; however, clinicians may significantly reduce the number of possibilities by obtaining an accurate history, performing a thorough physical examination, and realizing that the differential diagnosis for neck masses is relatively age-dependent.2

Anatomy

An understanding of neck anatomy is crucial when evaluating neck masses, because the location of a neck mass and its relationship to surrounding structures must be considered when determining the differential diagnosis.3 The clinician must recognize the location of major neck structures and understand the neck's lymphatic drainage system to differentiate between normal and abnormal findings.

Clinicians must also be familiar with the various landmark neck structures that are often palpable within the head and neck region: the parotid glands, the transverse process of Cl, the sternocleidomastoid muscle, the hyoid bone, the thyroid cartilage, the cricoid cartilage, the trachea, and the lower border of the mandible (see Figure 1).4

A general knowledge of the neck's lymph node anatomy is also essential, because enlarged lymph nodes are the most common type of neck mass.5 The head and neck region contain approximately 300 lymph nodes.5, 6 The cervical lymphatic system consists of interconnected groups, or chains, of nodes that parallel the major neurovascular structures in the head and neck.7,8

The major cervical lymph node locations to consider when evaluating neck masses are the postauricular, preauricular, posterior triangle, midjugular, low jugular, supr y, and submental areas (see Figure 2).9,10 The skin and mucosal surfaces of the head and neck have specific nodes associated with them; consequently, knowledge of the location and the drainage patterns of the cervical lymph nodes is necessary when narrowing the differential diagnosis.10

Subjective History

The evaluation of a neck mass begins with a careful patient history. A logical series of questions may quickly narrow the diagnostic possibilities and streamline the subsequent examination and management(see Table 1) 4,7,11

Neck masses in children tend to be inflammatory or congenital in nature. The majority of neck masses presenting in children are benign.4,12,13 However, the possibility of a malignant lesion, especially lymphoma, should not be excluded, particularly in the presence of abnormal hematologic values, weight loss, enlarged liver/spleen, fixed lymph nodes, or groin/axilla adenopathy.4

The incidence of congenital masses decreases in young adults ages 18 to 40, but these masses may still be diagnosed in patients in their twenties. The majority of masses in young adults are also inflammatory in nature (for example, mononucleosis or strep throat).4,12,13 AIDS-related lymphoma or Kaposi's sarcoma must be ruled out, particularly if the patient is at high risk for AIDS and has other associated symptoms. Similarly, lymphomas should not be excluded in this age-group, particularly if other associated symptoms are present.

Squamous cell carcinomas of.the head and neck region are rare in this age-group.14 In patients age 40 or older, the likelihood of a malignant neck mass increases substantially.15 In patients over age 40 who smoke or regularly drink alcohol, "the rule of 80s" should be considered. This rule states that in individuals over age 40, 80% of all nonthyroid neck masses are neoplastic; 80% of these neoplasms are malignant; 80% of these malignant lesions are metastatic lesions; and 80% of these metastatic lesions arise from primaries that are above the clavicle.1