The Accessory Parotid Gland and its Clinical Significance:

Evaluation of the anterior processes of the parotid gland: an ultrasonographic study

OBJECTIVES

This study aimed to determine the prevalence of anterior extensions of the parotid gland (AEPG), namely the accessory parotid gland (APG) and the facial process of the parotid gland (FP), using ultrasonography.

STUDY DESIGN

A total of 338 parotid glands were scanned bilaterally. APG was defined as a soft tissue mass with the same echogenic features as the main parotid gland (MPG) and not in contact with it, while FP was defined as an extension that exceeded the anterior border of the mandibular ramus and was continuous with the MPG. The anteroposterior, mediolateral, superoinferior dimensions and the mean distance from the MPG to the APG were measured.

RESULTS

The prevalence of APG and FP were 19.5% and 36%, respectively, resulting in an AEPG prevalence of 55.6%. The presence of APG was statistically higher in females than in males (p = 0.039). The mean anteroposterior, mediolateral, and superoinferior dimensions of the APG were 18.1 ± 0.57 mm, 0.35 ± 0.17 mm, and 12.3 ± 0.36 mm, respectively, and the mean distance from the MPG was measured as 12.1 ± 0.87 mm.

CONCLUSION

This study can raise awareness among clinicians about the presence of AEPG in the differential diagnosis of mid-cheek masses.

Transoral Excision of a Large Accessory Parotid Gland Tumor

Accessory parotid gland (APG) tumors account for 1% to 7% of all parotid gland neoplasms but are more likely to be malignant than main parotid gland tumors. Management of APG neoplasms entails surgical excision. Four primary approaches to resection have been described in the literature with varying facial nerve outcomes. We report a case of a 4-cm APG pleomorphic adenoma utilizing a transoral approach for excision without postoperative facial nerve injury. A transoral approach is known to mitigate patients' cosmetic concerns; however, prior reports utilized endoscopic assistance on patients with smaller tumors. We conclude that large APG tumors can be excised through a transoral approach without undue risk to the distal facial nerves, though this transoral approach ultimately may not be appropriate for malignant neoplasms or difficult dissections.

Imaging of Major Salivary Gland Lesions and Disease

Infectious and inflammatory disorders are the commonest pathologies to affect the major salivary glands however frequently overlap in clinical presentation. Imaging plays an important role in diagnosis, usually initially performed by CT or ultrasound. MRI, with its superior soft-tissue characterization compared with CT, provides a better evaluation of tumors and tumor-like conditions. Imaging features may suggest that a mass is more likely to be benign versus malignant, however, biopsy is often needed to establish a definitive histopathologic diagnosis. Imaging plays a key role in the staging of neoplastic disease.

Does three-dimensional intraglandular location predict malignancy in parotid tumors?

Tumors arising within the parotid encompass a heterogeneous mix of benign and malignant neoplasms and other tissue growths. The purpose of this study was to determine the association between the location of intraparotid masses and the risk of malignancy. A retrospective cohort study was performed of patients diagnosed with parotid tumors following open tumor excision. The primary predictor variable was the location of the epicenter of the tumor in three-dimensional space, as determined from preoperative imaging. Other variables were patient demographics and clinical parameters. The primary outcome variable was the final histopathologic diagnosis of a benign or malignant process. A χ² analysis was performed to test for any significant associations between demographic, clinical, and radiographic factors in relation to the outcome, and backwards stepwise logistic regression analysis was used to control for variables. Both increasing age (P = 0.002) and the presence of local pain (P = 0.020) were associated with malignancy. Tumors located anterior to the posterior border of the retromandibular vein had 2.18 times higher odds of malignancy (95% confidence interval 1.13-4.21; P = 0.020). Multivariate regression analysis suggested that patient age, the presence of pain, and tumor location anterosuperiorly and superoinferiorly could all assist in determining the odds of malignancy.

Contouring the accessory parotid gland and major parotid glands as a single organ at risk during nasopharyngeal carcinoma radiotherapy

Background and purpose

No research currently exists on the role of the accessory parotid gland (APG) in nasopharyngeal carcinoma (NPC). We thereby aimed to assess the effects of APG on the dosimetry of the parotid glands (PGs) during NPC radiotherapy and evaluate its predictive value for late xerostomia.

Material and methods

The clinical data of 32 NPC patients with radiological evidence of the APG treated at Sun Yat-sen Memorial Hospital between November 2020 and February 2021 were retrospectively reviewed. Clinically approved treatment plans consisted of only the PGs as an organ at risk (OAR) (Plan1), while Plan2 was designed by considering the APG as a single organ at risk (OAR). The APG on Plan1 was delineated, and dose–volume parameters of the PGs alone (PG-only) and of the combined structure (PG+APG) were analyzed in both plans. The association of such dosimetric parameters in Plan1 with xerostomia at 6–9 months post-radiotherapy was further explored.

Results

Fifty APGs were found, with a mean volume of 3.3 ± 0.2 ml. Significant differences were found in all dosimetric parameters between Plan1 and Plan2. The mean dose and percentage of OAR volumes receiving more than 30 Gy significantly reduced in Plan1 itself (PG-only vs. PG+APG, 39.55 ± 0.83 Gy vs. 37.71 ± 0.75 Gy, and 62.00 ± 2.00% vs. 57.41 ± 1.56%, respectively; p < 001) and reduced further in Plan2 (PG+APG, 36.40 ± 0.74 Gy, and 55.54 ± 1.61%, respectively; p < 0.001). Three additional patients met the dose constraint in Plan1, which increased to seven in Plan2. With APG included, the predictive power of the dosimetric parameters for xerostomia tended to improve, although no significant differences were observed.

Conclusion

APG is anatomically similar to the PGs. Our findings suggest the potential benefits of treating the APG and PGs as a single OAR during radiotherapy (RT) of NPC by improving PG sparing.

Conventional and MR-sialography of accessory submandibular glands: A case report

Our review of the literature shows anatomical variation of the submandibular gland is a rare entity, unlike the variation that can be seen in parotid glands. Specifically, bilateral submandibular abnormality has only been reported on one occasion with limited imaging in our review. We report a 78-year-old female with a history of sialadenitis and sialolithiasis who presents with swelling and pain in the right submandibular gland. Sialography of the right submandibular gland disclosed a second primary duct branching off the main duct to a second submandibular gland. Cannulation of the left submandibular duct was unsuccessful due to scarring of the duct orifice; however, subsequent MR sialography identified marked submandibular duct dilation and the incidental finding of a second anteriorly located left submandibular gland. The anatomic detail provided by conventional digital sialography is contrasted to the useful but less-defined imaging provided by MR sialography. To our knowledge, this is the first reported case of bilateral accessory submandibular glands that has been evaluated using both conventional and MR sialography.

Ultrasound in Inflammatory and Obstructive Salivary Gland Diseases: Own Experiences and a Review of the Literature

Background: Ultrasound is established as a diagnostic tool in salivary glands for obstructive diseases such as sialolithiasis and tumors. Concerning inflammatory diseases and in non-sialolithiasis-caused obstruction, much fewer data are available. In recent years, technical development has allowed a better assessment of the gland parenchyma, and knowledge about intraductal pathologies has increased considerably, which has provided new insights and a new interpretation of ultrasound findings. Objectives: To provide a comprehensive review of the literature that includes our own experiences and to point out the state of the art in ultrasound in the diagnostics of inflammatory and obstructive salivary gland diseases, taking adequate techniques and recent technical developments into consideration. Data sources and study eligibility criteria: A systematic literature search was performed in Pubmed using various specific key words. Results: According to the literature results, including our own experiences, ultrasound is of value in up to >90% of cases presenting with inflammatory and/or obstructive diseases. Technical developments (e.g., elastography) and the application of modified ultrasound techniques (e.g., transoral ultrasound) have contributed to these results. Today, ultrasound is considered a first-line diagnostic tool in these diseases. However, in some inflammatory diseases, the final diagnosis can be made only after inclusion of the anamnesis, clinical symptoms, serologic blood tests, or histopathologic investigation. Conclusions: Ultrasound can be considered as a first-line diagnostic tool in obstructive and inflammatory salivary gland diseases. In obstructive diseases, it may be sufficient for diagnostics in >90% of cases. In inflammatory diseases, ultrasound is at least an excellent screening method and can be used to establish the diagnosis in cases of an early suspicion. In all diseases ultrasound can contribute to better management and can be used for monitoring during follow-up.

Morphological Boundaries of the Parotid Gland in Koreans

ABSTRACT

This study aimed to examine the accurate location and boundary of the parotid gland in Koreans.Forty hemifaces from embalmed cadavers (mean age: 73 years) were studied. The line connecting the porion, gonion, and gnathion was used as a reference line. To measure the boundary of the parotid gland, the Frankfort horizontal line was used as the x-axis, whereas the vertical line passing through the porion was used as the y-axis. All measurements were taken from the lateral side of the face.The parotid gland has a variety of shapes: irregular, reverse triangle, and falciform. In all specimens, the boundary of the parotid gland was located 20 to 60 mm below the Frankfort horizontal line and located 10 mm anterior to the y-axis. On average, the most anterior and posterior distances of the parotid gland from the porion-gonion line were 36.4 ± 13.9 mm and 20.1 ± 10.5 mm, respectively, and the most inferior distance of the parotid gland from the gonion-gnathion line was 9.8 ± 5.8 mm. All specimens of parotid glands were found within an area 20 to 40 mm below the Frankfort horizontal line and 10 mm to the left of the y-axis. The most anterior point of the parotid gland was observed at varying locations. The maximum value of the most anterior point was 61.26 mm; it rarely exceeded the ectocanthion. The most posterior points of the parotid gland were located between the mastoid process and sternocleidomastoid muscle.These results might be useful for preventing injury to the parotid gland during facial rejuvenation procedures.

Ten must know pseudolesions of the head and neck

Patients may present in the emergency setting for a variety of head and neck complaints such as fever, trouble swallowing, or a newly palpable mass. When reviewing radiologic head and neck exams for etiology of complaints, it is important to be familiar with the multiple pseudolesions that may mimic pathology. These may be normal variant anatomy, normal anatomy located in an atypical location, as well as iatrogenic or self-introduced foreign bodies. This review article discusses ten common pseudolesions encountered in the head and neck and their typical imaging appearance so that one does not mistake them for ominous pathology, thus preventing unnecessary follow-up, biopsy, or continued concern for the patient.