Diagnostic Workup
After initial prescreening during the telemedicine encounter, patients
with signs or symptoms of a salivary gland mass should undergo
diagnostic imaging. All patients must be screened for symptoms of
COVID-19 or risk factors for exposure prior to their visit to the
radiology department. Imaging studies of the patients with the symptoms
concerning for COVID-19 should be cancelled and delayed until the
diagnosis is confirmed and they recover from their illness, or COVID-19
is ruled out with negative test results unless this delay has a high
probability of significant negative outcome for the
patient.7 The most up-to-date institutional guidelines
should be used to determine who needs COVID-19 testing. If possible,
patients must undergo imaging at the sites with less foot traffic and
with fewer critically ill patients to prevent secondary exposure to
COVID-19.
The goal of radiographic evaluation is to assist in the triage of
patients with a suspected salivary gland mass and to determine if the
patient has a lesion requiring a tissue diagnosis for treatment
recommendations. The most readily available imaging studies must be
utilized with the preference given to ultrasonographic evaluation due to
ease of performance and the ability to immediately obtain a fine-needle
aspiration biopsy (FNAB) of identified lesions for cytopathologic
analysis (Table 1). Since several benign and malignant salivary gland
lesions can present with minor or predominant cystic component, and one
third of cystic salivary gland lesions are
neoplastic,8 presence of a cystic component on
ultrasonography should not serve as a determining factor in the decision
to proceed with FNAB. Salivary gland ultrasound can also aid in the
diagnosis of sialolithiasis or other inflammatory salivary gland
conditions, and guide further treatment
recommendations.9,10 If FNAB cannot be done,
consideration should be given to contrast-enhanced magnetic resonance
imaging (MRI) instead of the ultrasound to confirm presence of a
salivary gland mass and to look for radiographic features of common
benign or malignant salivary gland tumors.
Clinical situations of radiographically diagnosed salivary gland masses,
especially deep parotid lobe masses not amenable to FNAB must be
approached on a case-by-case basis with diagnostic options of either
computed tomography (CT) guided biopsy or surgical resection. The final
diagnostic choice will depend on the availability of the hospital’s
interventional radiology department and COVID-19 burden. For patients
with minor salivary gland tumors of the oral cavity, sinonasal region
and pharynx diagnosed based on the office-based biopsy, appropriate
cross-sectional imaging of the head and neck should be performed upfront
to determine the extent of the lesion and the treatment plan.
Telemedicine visits can be used to determine the best location for
salivary gland imaging. Good knowledge of local private imaging
facilities willing to perform salivary gland ultrasound, FNAB or other
head and neck imaging when the hospitals with high volume of COVID-19
patients postpone it will help determine best options for radiology
referrals. Fortunately, evaluation of major salivary gland neoplasms can
be done without oral or nasal examination, and some otolaryngology
physicians have the capabilities to perform an ultrasound and an FNAB in
the office. After completion of salivary gland ultrasound and FNAB, MRI
with contrast must be reserved for preoperative planning in patients
with time-sensitive diagnosis such as salivary gland malignancy and can
be ordered on the basis of the US and the FNAB results if indicated.
Imaging of sialolithiasis and other inflammatory salivary gland
conditions (CT or sialo-MRI) should be postponed in the majority of
patients. However, in rare situations such imaging might become
unavoidable (Figure 1).
Ultrasound characteristics alone cannot distinguish benign from
malignant salivary gland masses, and must be considered in conjunction
with the FNAB results.11,12 FNAB results can be
stratified by the Milan System for Reporting Salivary Gland Cytology
(MSRSGC)13-14 to render treatment recommendations.
Repeat FNAB must be considered if the initial FNAB results are
interpreted as “non-diagnostic” (Table 2). Personal protective
equipment (PPE) should be used appropriately while performing FNAB
procedures and handling specimens according to the College of American
Pathologist guidelines.15 Only essential members of
the health care team should be present during the FNAB procedure to
reduce exposure as expelling aspirates may generate droplets or
aerosols. In addition, agitating air-dried smears should be minimized.