From the Guidelines
A small lymph node visualized on ultrasound at the back of the neck that is not pathologically enlarged is likely a normal finding.
Key Points
- The presence of a small lymph node in the neck is a common finding, especially in adults, and can be a normal variant or a reactive process 1.
- The American College of Radiology recommends contrast-enhanced CT or MRI for patients with a neck mass deemed at risk for malignancy, but ultrasound can be used as an initial imaging option for suspected thyroid or salivary masses 1.
- The significance of a small lymph node in the neck depends on the clinical context, including the patient's age, symptoms, and medical history, with a higher suspicion for malignancy in patients over 40 years old, especially with a smoking history 1.
- Imaging findings should be correlated with clinical evaluation and histology to confirm any suspected malignancy 1.
Imaging Modalities
- Ultrasound is a useful initial imaging modality for evaluating neck masses, particularly for suspected thyroid or salivary masses 1.
- Contrast-enhanced CT is the preferred initial imaging modality for a palpable nonpulsatile neck mass in an adult, due to its superior spatial resolution and ability to identify abnormal lymph nodes 1.
From the Research
Significance of a Small Lymph Node
The presence of a small lymph node at the back of the neck that is not pathologically enlarged may not necessarily be a cause for concern. According to 2, metastatic deposits in normal-sized lymph nodes can be smaller than a millimeter, making them a diagnostic challenge.
Ultrasound Evaluation
Ultrasound is a reliable method for lymph node characterization, especially in subcutaneous areas 2, 3. However, distinguishing between benign and malignant lymphadenopathies can be difficult using B-mode and Doppler-ultrasound criteria alone 2.
Features of Abnormal Lymph Nodes
Certain features can help distinguish abnormal from normal cervical lymph nodes, including:
- Peripheral vascularity
- Shape
- Overall lymph node echogenicity
- Absence of hilus
- Presence of nodal microcalcifications
- Cystic changes 4 These features can be evaluated using ultrasound to assess the likelihood of malignancy.
Clinical Implications
The presence of enlarged cervical lymph nodes can be associated with an increased likelihood of thyroid malignancy 5. However, the significance of a small, non-pathologically enlarged lymph node is less clear. Further evaluation and correlation with clinical findings and other diagnostic tests may be necessary to determine the clinical significance of such a finding.