From the Guidelines
To rule out a neck mass versus lymphadenopathy, I would request a contrast-enhanced CT or MRI of the neck. This recommendation is based on the strongest and most recent evidence, which suggests that CT or MRI with contrast is the preferred imaging modality for evaluating neck masses, especially in patients at increased risk for malignancy 1.
The use of CT or MRI with contrast allows for the localization and characterization of the mass, assessment of additional nonpalpable masses, and screening of visualized organs for potential primary malignancy. While ultrasound is a useful tool for characterizing superficial tissue and guiding percutaneous tissue sampling, it may not adequately visualize most portions of the upper aerodigestive tract, where many primary tumors arise 1.
Some of the key benefits of CT include its widespread availability, lower cost, and shorter scanning time, making it a more easily tolerated procedure for patients. However, MRI offers improved tissue contrast and is preferred when a primary tumor of the nasopharynx is suspected or when there is cranial nerve abnormality on physical examination.
Key features to assess on the imaging study include the size, shape, borders, internal architecture, and vascularity of the mass, as well as the presence of any additional masses or lymphadenopathy. The imaging study should extend from the skull base to the thoracic inlet to adequately capture all structures for evaluation.
It's worth noting that the choice between CT and MRI ultimately depends on the specific clinical scenario and patient factors, such as the presence of implantable medical devices or dental artifact that may obscure visualization of certain areas. However, based on the available evidence, contrast-enhanced CT or MRI of the neck is the recommended initial imaging modality for evaluating neck masses.
From the Research
Ultrasound Options for Neck Mass vs Lymphadenopathy
To differentiate between a neck mass and lymphadenopathy, the following ultrasound options can be considered:
- High-frequency ultrasound for superficial structures 2
- Ultrasound-guided fine-needle aspiration (USFNA) for lymphadenopathy 3, 4, 5
- Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for lymphadenopathy 6
- Core needle biopsy (CNB) for axillary lymphadenopathy 5
Characteristics of Ultrasound Options
The characteristics of these ultrasound options include:
- High-frequency ultrasound: high spatial resolution imaging of superficial structures, suitable for skin, blood vessels, musculoskeletal anatomy, oral mucosa, and small parts 2
- USFNA: systematization and standardization of lymph node FNA methodology, increased efficacy and efficiency 3
- EUS-FNA: safe and less invasive method for obtaining pathologic specimens from extraluminal lesions, useful for diagnosing and determining the management of lymphadenopathy 6
- CNB: excellent diagnostic performance, useful for diagnosing and managing axillary lymphadenopathy 5
Diagnostic Performance
The diagnostic performance of these ultrasound options is as follows:
- USFNA: sensitivity, specificity, and accuracy of 0.909,0.900, and 0.917 for FNA, 0.958,1.000, and 0.970 for CNB, and 0.941,0.952, and 0.945 for FNA + CNB 5
- EUS-FNA: diagnostic sensitivity, specificity, positive and negative predictive value, and overall accuracy were 95.3,100,72.7 and 95.8%, respectively 6