Incidental pneumoparotid detected on computed tomography: Should it raise an alarm?

Pneumoparotid: Practical impact of Surgeon performed Ultrasound in an effective Diagnostic Approach

OBJECTIVES

Pneumoparotid is characterized by air inclusions in the parotid duct system. Use of ultrasound has proved valuable for evaluating air inclusions in various parts of the body; the diagnostics of this condition has not been systematically analyzed, however. The aim of this study was to evaluate the value of ultrasound in the detection of air inclusions along the parotid duct system and its closer characterization.

METHODS

Retrospective analysis was carried out of patients diagnosed with pneumoparotid between 2005 and 2020 in a salivary gland center. Ultrasound was performed in all cases, and features of air inclusions were described. Reference standard was the clinical demonstration of foamy saliva after gland massage and/or sialendoscopic evidence of intraductal air inclusions.

RESULTS

Twenty-one patients were identified (48.8 ± 3.8 years). Two were associated with wind instruments; seven were iatrogenic, following treatment for duct stenosis; one after radiotherapy; four with known bruxism and seven were idiopathic and without associated conditions. On ultrasound examination, pneumoparotid was characterized by three phenomena: flattened, mobile hyperechoic reflexes, dirty shadows with reverberation or "sunbeam effect," and shifting shadows during gland massage.

CONCLUSIONS

Ultrasound was useful for characterizing pneumoparotid in a fast and practical way and could serve as imaging tool of first choice.

Etiology of Pneumoparotid: A Systematic Review

Pneumoparotid describes retrogradely insufflated air within the Stensen's duct and/or parotid gland. It is a rare condition with variable causative factors. This study aimed to elucidate the clinical characteristics of pneumoparotid. Reports in all languages were evaluated following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement 2020. A literature search was conducted using electronic medical databases (PubMed, Scopus, Web of Science, EBSCO, Ovid, Google Scholar, SciElo, LILIACS, and others) from 1890 to 30 June 2022. One hundred and seventy patients (mean age; 28.4 years) from 126 studies were reviewed. Common symptoms included swelling (84.7%) and pain (35.9%). Characteristic findings were crepitus in the parotid region (40%) and frothy saliva from the orifice (39.4%). The common etiologies included abnormal habits such as blowing out the cheeks (23.5%), idiopathic (20%), self-induced (15.9%), playing wind instruments such as trumpets or flutes (8.8%), and diseases inducing coughing or sneezing (8.2%). The treatments included antibiotic therapy (30%), behavioral therapy to avoid continuing causative habits (25.9%), psychiatric therapy (8.2%), and surgical procedures (8.2%). Treatment should be individualized and etiology-based. However, the etiology was not identified in 20% of patients. Further detailed data from larger samples are required to clarify and improve the recognition of this entity.

Pneumoparotid in "puffed cheek" computed tomography: incidence and relation to oropharyngeal conditions

Pneumoparotid is common in patients with lesions of the oral cavity who have diagnostic computed tomography (CT) with the "puffed cheek" technique. Although such observations are often noted, we could find few papers about the incidence in relation to oropharyngeal conditions. We present a retrospective series of 47/300 patients who developed pneumoparotid during multidetector CT examination of the oropharyngeal region to assess the incidence and any possible correlation with regional disease. Patients were followed up for any symptoms and also for complications. In 14 patients the pneumoparotid was right-sided, in 17 left-sided, and in 16 it was bilateral. There was a significant association between the incidence of pneumoparotid and the site of disease, it being stronger (p<0.001) with lesions in the oral cavity than with those in the oropharynx and hypopharynx. Apart from brief discomfort, none of the patients had any symptoms after the procedure. In summary, pneumoparotid developed in 47/300 (16%) of our patients after multidetector CT when the "puffed cheek" technique was used, and was more common in patients with lesions of the oral cavity and anterior tongue than among patients with lesions of the oropharyngeal, nasopharyngeal, and hypopharyngeal regions. Few patients experienced transient fullness immediately after the procedure. None of our patients had lasting or infective symptoms.