Contemporary Use of Imaging Modalities in Neck Mass Evaluation

The effective and efficient management of a patient with a neck mass in a 1-stop clinic requires a collaborative and harmonious partnership among surgeon, radiologist, and pathologist. In this article, theoretic and practical issues are addressed to optimize patient care when prescribing, planning, performing, and interpreting imaging for neck disease.

Key points

  • The incidence of new cases of head and neck cancer in the United Kingdom is approximately 8100.

  • In most patients presenting with neck masses, the diagnosis is benign.

  • The clinical effectiveness and efficiency of separating malignant from benign not only has a significant impact for the patient but also economic benefit to health care providers.

Introduction

A patient presenting to clinic with a neck lump is a common scenario for oral and maxillofacial/head and neck surgeons. In this article, the diagnosis and management of common and important neck masses are discussed, with particular focus on the various roles of imaging. The focus is on adult neck lumps. Thyroid lumps and pediatric cervical swellings are excluded from this discussion. More emphasis is placed on the practicalities of imaging and management rather than the provision of an exhaustive list of differential diagnoses.

In our department, 900 new patients present to a designated 1-stop neck lump clinic annually. The service allows regional general medical and dental practitioners the opportunity for rapid referral of patients with neck lumps of concerning origin. Most patients attending the 1-stop clinic receive senior clinician assessment, coupled with immediate ultrasonography (US) and cytologic investigations, where indicated. By the end of the patient’s visit to the clinic, the patient receives a preliminary diagnosis and a scheduled investigative time scale. After a contemporary departmental audit, approximately 12% of these new referrals are diagnosed as malignant.

Approximately 8100 new cases of head and neck cancer are registered in England annually. Seventy-three percent of patients in the United Kingdom with head and neck cancer are referred from primary care under the urgent or 2-week referral system. In the United Kingdom, the incidence of cancer with unknown primary is 10,000, many of these present as cervical malignancy with undiagnosed primary origin.

In our clinic, most presenting neck lumps are benign, with reactive or suppurative lymphadenopathy, lipomata, and superficial and deep cervical cysts. Benign disease of the parotid tail and submandibular and sublingual glands are also common presentations. Less frequent referrals relate to variations of normal anatomy: a prominent carotid bulb or a spinous process of cervical vertebra or a cervical rib.

The radiology team has an important role in the assessment and diagnosis of neck lumps. In particular, the ability of the radiologist to identify cancer spread and accurately stage malignancy is a key and often pivotal role in influencing treatment at the multidisciplinary team meeting. This situation has reflected the advances across the field of imaging in recent times. In this article, the imaging modalities available are reviewed, highlighting their merits and hurdles of use, and, second, the common and significant neck lumps presenting to our head and neck clinic are reviewed.

Introduction

A patient presenting to clinic with a neck lump is a common scenario for oral and maxillofacial/head and neck surgeons. In this article, the diagnosis and management of common and important neck masses are discussed, with particular focus on the various roles of imaging. The focus is on adult neck lumps. Thyroid lumps and pediatric cervical swellings are excluded from this discussion. More emphasis is placed on the practicalities of imaging and management rather than the provision of an exhaustive list of differential diagnoses.

In our department, 900 new patients present to a designated 1-stop neck lump clinic annually. The service allows regional general medical and dental practitioners the opportunity for rapid referral of patients with neck lumps of concerning origin. Most patients attending the 1-stop clinic receive senior clinician assessment, coupled with immediate ultrasonography (US) and cytologic investigations, where indicated. By the end of the patient’s visit to the clinic, the patient receives a preliminary diagnosis and a scheduled investigative time scale. After a contemporary departmental audit, approximately 12% of these new referrals are diagnosed as malignant.

Approximately 8100 new cases of head and neck cancer are registered in England annually. Seventy-three percent of patients in the United Kingdom with head and neck cancer are referred from primary care under the urgent or 2-week referral system. In the United Kingdom, the incidence of cancer with unknown primary is 10,000, many of these present as cervical malignancy with undiagnosed primary origin.

In our clinic, most presenting neck lumps are benign, with reactive or suppurative lymphadenopathy, lipomata, and superficial and deep cervical cysts. Benign disease of the parotid tail and submandibular and sublingual glands are also common presentations. Less frequent referrals relate to variations of normal anatomy: a prominent carotid bulb or a spinous process of cervical vertebra or a cervical rib.

The radiology team has an important role in the assessment and diagnosis of neck lumps. In particular, the ability of the radiologist to identify cancer spread and accurately stage malignancy is a key and often pivotal role in influencing treatment at the multidisciplinary team meeting. This situation has reflected the advances across the field of imaging in recent times. In this article, the imaging modalities available are reviewed, highlighting their merits and hurdles of use, and, second, the common and significant neck lumps presenting to our head and neck clinic are reviewed.

Anatomic classification of the neck

Cervical Lymphatic Classification

The extensive lymphatic system in the head and neck provides a physiologic mechanism for channeling fluid, cells, and protein from the interstitium into the systemic circulation. There are approximately 300 lymph nodes within this region, which account for 40% of the total body lymph nodes. An understanding of the head and neck lymphatic system is needed in the management of patients with head and neck cancer with regional metastasis. Lymphatics in the neck have been classified into superficial and deep systems ( Fig. 1 ). The superficial system arising in the reticular dermis and superficial cervical fascia and the deep lymphatic circulation functions beneath the investing layer of the deep cervical fascia ( Table 1 ). The American Head and Neck Society and American Academy of Otolaryngology–Head and Neck Surgery organized the cervical lymphatic system into separate levels, reflecting patterns of drainage ( Fig. 2 , Table 2 ). This division provides reproducible anatomic localization for both surgeon and radiologist.

Fig. 1
Anterior and posterior triangles of the neck. Anterior: submental ( blue ), submandibular ( green ), muscular ( orange ), carotid ( purple ); posterior ( red ).

Table 1
Cervical triangles: boundaries and contents
Cervical Triangle Boundaries Contents
Anterior
Submental Neck midline
Lower border of mandible
Anterior belly of digastric muscle
Submental vessels uniting with anterior jugular vein
Level Ia lymph nodes
Submandibular Lower border of mandible
Anterior belly and digastric
Posterior belly of digastric muscle
Facial vessels
Level Ib lymph nodes
Submandibular gland
Marginal mandibular branch of facial nerve
Hypoglossal nerve
Carotid Mid third of sternomastoid muscle (anterior margin)
Posterior belly of digastric muscle
Superior belly of omohyoid
Bifurcation of common carotid artery
Carotid branches (superior thyroid, lingual, facial, occipital, ascending pharyngeal)
Internal jugular vein and tributaries (superior thyroid, lingual, common facial, ascending pharyngeal, occipital)
Sympathetic trunk
Vagus nerve
Hypoglossal nerve
Cervical plexus
Spinal accessory nerve
Level II/III lymph nodes
Upper larynx/lower pharynx
Muscular Lower third of sternocleidomastoid (anterior margin)
Superior belly of omohyoid
Median line of neck (hyoid to sternum)
Carotid sheath (common carotid artery, internal jugular vein, vagus nerve, sympathetic trunk)
Ansa cervicalis
Inferior thyroid artery and vein
Esophagus
Thyroid gland
Trachea
Lower part of larynx
Recurrent laryngeal nerve
Level II/III lymph nodes
Posterior Anterior border of trapezius
Middle third of clavicle
posterior border of SCM
Transverse cervical vessels
Distal part of subclavian artery
Suprascapular artery
Lower part of external jugular vein
Level V lymph nodes
Spinal accessory nerve
Cervical plexus
Phrenic nerve (C3,4,5)

Fig. 2
The American Head and Neck Society and American Academy of Otolaryngology–Head and Neck Surgery classification of cervical lymph nodes shown on a profile view of the neck.

Table 2
The American Head and Neck Society and American Academy of Otolaryngology–Head and Neck Surgery classification of cervical lymph nodes
Level Anatomic Site Draining Source
IA Submental triangle Lips, chin, nasal tip, incisors/canines
IB Submandibular triangle Cheek, premolar and molar teeth, anterior tongue
IIA Base of skull to upper border of hyoid bone: anterior to SAN Oropharynx, anterior and posterior tongue
IIB Base of skull to upper border of hyoid bone: posterior to SAN Oropharynx, parotid
III Upper border of hyoid bone to upper border of cricoid Oropharynx, larynx
IV Upper border of cricoid to upper border of clavicle Oropharynx, larynx, upper thorax
VA Posterior triangle: anterior to SAN Occiput and scalp
VB Posterior triangle: distal to SAN Occiput and scalp
VI Lower border of hyoid to suprasternal notch. Lateral border is common carotid artery Thyroid gland, larynx, piriform sinus, esophagus
Abbreviation: SAN, spinal accessory nerve.
Adapted from Robbins KT, Shaha AR, Medina JE, et al. Consensus statement on the classification and terminology of neck dissection. Arch Otolaryngol Head Neck Surg 2008;134(5):536–8.

Consultation appointment

With the space constraints of this article, the full history taking and examination process are not considered. However, the importance of targeted questions relevant to diagnosis must be highlighted. The fundamental aim of the clinic is to identify the malignant conditions from most referrals that prove benign. Patients presenting with an undiagnosed malignancy may have been suffering local, regional, and systematic symptoms associated with local tumor behavior and metastatic and paraneoplastic effects. In addition, questions about B symptoms in suspected lymphoma are recommended. A careful social history analyzing tobacco and alcohol habits and details of past sexual practice assigns a level of risk to the patient.

Specific questions on renal function and allergy are required before referring for radiologic investigations requiring intravenous contrast. Inherited and acquired coagulopathies need to be identified before invasive sampling. We have found that increasingly more patients attending clinic report taking new-generation antiplatelets (eg, prasugrel, ticagrelor, clopidogrel). These antiplatelets can be easily overlooked but require appropriate discussion with hematology colleagues before investigative procedures and treatment.

A routine head and neck examination should be performed, which should include an oral examination and flexible nasal endoscopy. Clues from the history may encourage the clinician to examine the chest, axillae, abdomen, and nervous system.

Findings and recommendations from the Eighth Annual Review of Data Analysis of Head and Neck Oncology showed that only 80% of patients had TNM cancer staging and 66% performance status recorded at the time of multidisciplinary team discussion. The initial consultation is an ideal time to start collecting this information.

Imaging modalities in the assessment of neck lumps

Radiology is continually and rapidly advancing and forms a critical component of the diagnostic pathway for investigating neck lumps. Faster image acquisition, improved resolution, and expanding software capabilities all contribute to more detailed and more informative imaging.

The main imaging modalities used in the assessment of lumps presenting in the head and neck are US, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). An overview of their strengths and weaknesses is provided in Table 3 , with guidance related to image acquisition.

Table 3
Imaging modalities: summary of strengths, weaknesses, and practical tips
Modality Strengths Weaknesses Tips and Technique
US
  • Cheap and available

  • Patient friendly:

    • No safety issues

    • Patient does not have to lie completely still

    • No ionizing radiation

  • High-resolution real-time imaging

  • US-guided fine-needle aspiration and biopsy

Operator dependent; neck US best performed by specialist head and neck radiologist
Limited depth penetration
Limited visualization of bony structures
Patient scanned with neck extended
High-frequency probe (8–12 MHz)
CT
  • Available

  • Patient friendly:

    • Quick (<5 min to complete scan)

    • Not claustrophobic

    • No breath hold required

    • Kyphotic patients can be scanned

  • Single supine scan with volumetric data allowing multiplanar reconstruction

  • Good anatomic localization

  • Excellent bony detail

  • Can simultaneously image the chest for staging in the setting of malignancy

Uses ionizing radiation
Requires intravenous iodinated contrast for optimum visualization of structures in the neck
Image quality degraded by artifact from dental amalgam and swallowing
Limited soft tissue characterization
Scan during quiet breathing
Slow intravenous injection of contrast (100 mL injected at 1 mL/s and scanned at 100 s) for arterial, venous. and soft tissue enhancement
MRI Excellent soft tissue characterization
No ionizing radiation
  • Expensive and less readily available

  • Less patient friendly than CT:

    • Safety issues with implants (eg, pacemaker)

    • Longer scan time (typically 30 min)

    • Scan quality degraded by motion artifact

    • Claustrophobia can be an issue

    • Unable to scan kyphotic patients

Scan with quiet breathing
Fat-saturated postcontrast T1 sequence makes pathologic enhancement more conspicuous
Acquire diffusion-weighted sequence
PET/CT Provides functional data regarding metabolic activity of the primary tumor and any metastatic disease
Wider scan range (typically skull base to mid thighs or whole body)
Expensive and limited availability
High ionizing radiation dose

Ultrasonography

US is commonly the first-line imaging modality for assessing neck lumps. It is a quick, well-tolerated examination, which is widely available and offers a high spatial resolution without the use of ionizing radiation. Furthermore, US allows real-time guidance for fine-needle aspiration (FNA) cytology (FNAC) and core biopsy when a tissue sample is required. The main disadvantages of US are that it is limited to relatively superficial structures and is user dependent, with a high level of expertise required for the assessment of neck disease. Image quality is improved if good neck extension can be achieved ( Fig. 3 ).

Jan 23, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Contemporary Use of Imaging Modalities in Neck Mass Evaluation
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