Patient and tumor characteristics predictive of primary parotid gland malignancy: A 20-year experience at the University of Wisconsin

Minimal Margin Surgery and Intraoperative Neuromonitoring in Benign Parotid Gland Tumors: Retrospective Clinical Study

Extracapsular dissection (ECD) was introduced for the removal of superficial and small benign parotid tumors. According to a recent proposal, ECD is reserved for tumors that are 3 cm or less, mobile, and close to the parotid borders in cases of pleomorphic adenoma. The aim of the study is to evaluate the effectiveness of ECD for treatment of benign parotid tumors also in cases of tumors that were larger than 3 cm and deeper. All ECD for benign parotid neoplasms conducted between 2007 and 2017 were reviewed. The lesions included were limited to primary parotid tumors and categorized by Quer proposal. Facial nerve monitoring was used in all cases. Facial nerve palsy and local recurrences were assessed. The 88 ECD performed met inclusion criteria. The mean lesion size was 4.26 cm. Of the tumors, 68 were less than 3 cm in diameter and 20 were larger, 64 were superficial, and 24 were deep. The most common lesion types were pleomorphic adenoma (88.6%). There was no significant difference in complication rates between the size of tumor (p = 0.9) and location (p = 0.91). Our results suggest that extracapsular dissection could be considered an option for first-time diagnosed benign parotid tumors, even in cases of large dimensions and deep lobe involvement.

Prevalence and Clinical Implications of Incidentally Detected Parotid Lesions as Blind Spot on Brain MRI: A Single-Center Experience

Background and objective: This study was conducted to assess the prevalence and clinical implications of parotid lesions detected incidentally during brain magnetic resonance imaging (MRI) examination. Materials and Methods: Between February 2016 and February 2021, we identified 86 lesions in the brain MRI reports of 84 patients that contained the words “parotid gland” or “PG”. Of these, we finally included 49 lesions involving 45 patients following histopathological confirmation. Results: Based on the laboratory, radiological or histopathological findings, the prevalence of incidental parotid lesions was low (1.2%). Among the 45 study patients, 41 (91.1%) had unilateral lesions, and the majority of the lesions were located in the superficial lobe (40/49, 81.6%). The mean size of the parotid lesions was 1.3 cm ± 0.4 cm (range, 0.5 cm–2.8 cm). Of these, 46 parotid lesions (93.9%) were benign, whereas the remaining three lesions were malignant (6.1%). Conclusions: Despite the low prevalence and incidence of malignancy associated with incidental parotid lesions detected on brain MRI, the clinical implications are potentially significant. Therefore, clinical awareness and appropriate imaging work-up of these lesions are important for accurate diagnosis and timely management.

Clinicopathological features of incidental parotid lesions

Background

The purpose of this study is to determine the histopathological spectrum and risk of primary malignancy of asymptomatic parotid lesions incidentally discovered on cross-sectional imaging.

Methods

Over a 10-year period, 154 patients underwent 163 ultrasound-guided parotid lesion biopsies at our institution. This retrospective chart review included 89 lesions in 87 patients with asymptomatic parotid lesions discovered on cross-sectional imaging studies performed for unrelated clinical indications. The histopathologic findings of all sampled lesions were reviewed. We evaluated the patient demographics and pathological diagnoses of sampled parotid lesions to determine the histopathological spectrum and risk of malignancy.

Results

The average age was 67.5 years and 92 % were males. 25 % of patients had bilateral lesions. The average size of the parotid lesions was 1.5 cm and 91 % were located in the superficial lobe. 92.1 % of lesions were benign with Warthin tumor being the most common diagnosis followed by pleomorphic adenoma. 2.3 % of lesions were primary parotid malignant neoplasms, while 5.6 % were metastatic lesions in patients with known malignancy.

Conclusions

The incidence of primary parotid malignant neoplasm in asymptomatic incidentally discovered parotid lesions is low. Imaging or clinical follow-up may be considered in patients with incidental parotid lesions who prefer to avoid biopsy.

Extracapsular Dissection vs Superficial Parotidectomy of Benign Parotid Lesions: Surgical Outcomes and Cost-effectiveness Analysis

Importance

The clinical implications of extracapsular dissection over superficial parotidectomy are controversial and limited in data on cost-effectiveness.

Objective

To compare extracapsular dissection with superficial parotidectomy for benign parotid tumors with respect to surgical outcomes and cost-effectiveness.

Design, Setting, and Participants

This was a retrospective medical record review and cost-effectiveness analysis performed from August 2012 to November 2015 at a tertiary care institution. Adult patients (age ≥18 years) who underwent parotidectomy for benign parotid lesions were included.

Exposures

Treatment by extracapsular dissection or superficial parotidectomy.

Main Outcomes and Measures

Differences in postoperative complication rates and health services outcomes, including procedure time, anesthesia time, length of stay, and charges for surgeon, anesthesia, operating room, and hospital.

Results

A total of 46 parotidectomies consisting of 26 extracapsular dissections and 20 superficial parotidectomies met criteria. Of the 46 patients, 33 were women. Patient ages ranged from 18 to 83 years. Lesion features were similar between groups with most being pleomorphic adenoma. Procedure time (effect size, -1.31; 95% CI, -1.93 to -0.65), anesthesia time (effect size, -1.37; 95% CI, -1.99 to -0.70), and length of stay (effect size, -0.66; 95% CI, -1.25 to -0.05) were significantly shorter for extracapsular dissection compared with superficial parotidectomy. Moreover, anesthesia (effect size, -1.55; 95% CI, -2.19 to -0.86), operating room (effect size, -1.09; 95% CI, -1.69 to -0.45), and total hospital charges (effect size, -1.13; 95% CI, -1.74 to -0.49) were significantly less for extracapsular dissection while remaining charges, including surgeon, showed no difference. Finally, facial nerve weakness, great auricular nerve dysesthesia, and other relevant postoperative complications were comparable between groups.

Conclusions and Relevance

In the hands of an experienced surgeon, extracapsular dissection is a shorter, less costly, and equally safe alternative to traditional superficial parotidectomy when treating benign parotid lesions. Further follow-up is needed to ensure these perceived advantages are maintained over time.

Diagnostic value of metabolic heterogeneity as a reliable parameter for differentiating malignant parotid gland tumors

OBJECTIVE

Exact classifying between malignant and benign tumors in the parotid gland is important because the cancer has relatively poor prognosis. There have been several studies that F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) can differentiate between malignant and benign parotid gland tumors. However, the role of FDG PET is still controversial because many benign parotid gland tumors, such as Warthin's tumor and pleomorphic adenoma, show high FDG uptake. We hypothesized that metabolic heterogeneity would differentiate malignant parotid tumors because tumoral heterogeneity is an important characteristic in the malignancies.

METHODS

From January 2010 to April 2015, we retrospectively reviewed the 46 patients who showed FDG uptake at the parotid gland. To differentiate malignant parotid gland tumors, we obtained maximum SUV and mean SUV. Metabolic tumor volume and total lesion glycolysis were measured as metabolic volumetric parameters. We also included heterogeneity parameters of FDG PET such as heterogeneity factor (HF) and the coefficient of variation for all patients.

RESULTS

There was significant difference of HF between malignant (-0.30 ± 0.25; range -0.937 to -0.084) and benign parotid gland tumors (-0.06 ± 0.05; range -0.291 to -0.012; p < 0.0001). In receiver operating characteristic analysis, when ≤-0.084 was used as the cut-off value for HF, the sensitivity and specificity were 100 % (95 % CI 81.5-100) and 89.2 % (95 % CI 71.8-97.7), respectively. HF showed the highest area under the curve of 0.947 among the parameters. In logistic regression analysis, the HF was the most powerful factor for differentiation of the parotid gland tumors (p = 0.002).

CONCLUSIONS

Our results suggest that HF can be utilized as a reliable and non-invasive method for differentiation of malignant and benign parotid gland tumors.