Background/Purpose: With the diagnostic capability of the parotid gland biopsy similar to minor salivary gland biopsy in Sjögren’s syndrome, the parotid gland biopsy may also provide information on treatment response and development of lymphoma. Comparing complications of both procedures, facial nerve damage represents a risk of parotid gland biopsy, while transient numbness of the lower lip incision area may occur after minor salivary gland biopsy. Avoiding the facial nerve during the parotid gland biopsy, therefore, is essential. In recent years, high-frequency (15–25 MHz) ultrasound probes have become available for clinical use,  facilitating high-resolution visualization of small nerves or nerve fascicles.

We aimed to evaluate the diagnostic capability and safety of parotid gland biopsy in cadavers avoiding the region of the facial nerve under high-frequency (15–25 MHz) ultrasound guidance.

Methods: Prior to the parotid biopsy ultrasound exercise,  an ultrasound training session on healthy subjects was conducted with the aim of assessing the most suitable facial nerve-free area for biopsy was determined in healthy subjects using high-frequency ultrasound (Figure 1). Thereafter, nine rheumatologists with experience in salivary gland ultrasound performed ultrasound-guided biopsies from four parotid glands in two different cadavers with 18 G core biopsy needles (Figure 2).

Results: A total of 36 pathology specimens were evaluated histologically by the expert pathologist for the presence of parotid gland tissue and any vascular and neuronal tissue of the gland. Eighty percent of the 36 pathology preparations showed evidence of parotid gland tissue. Neuronal tissue was present in 2 specimens (5.5%), one with a very small amount of neuronal tissue. Vascular tissue was found in another 2 specimens (5.5%).

Conclusion: The present study has demonstrated that ultrasound-guided core needle biopsy of the parotid gland allows obtaining salivary gland tissue in the vast majority of cases. Longer procedural training would most likely improve the capability to obtain glandular samples.

Figure 1. Ultrasound image of a parotid gland. The facial nerve appears as a linear tubular like hypoechoic structure with hyperechoic rim inside the homogenous relatively hyperechoic parotid gland (Esaote MyLab 9 equipped with 6-24 MHz probe).

Figure 2. Core biopsy needle.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/ultrasound-guided-parotid-gland-biopsy-in-cadavers-performed-by-rheumatologists-an-omeract-ultrasound-working-group-study/