The Role of Real-Time Sonoelastography in the Differentiation of Benign From Malignant Parotid Gland Tumors

Abstract

Objective The aims of this study are to evaluate the utility of sonoelastography for parotid gland masses and to determine which cutoff strain ratio (SR) would be best for the differentiation between benign and malignant lesions. Methods From August 2015 to December 2016, 39 parotid gland masses were examined prospectively by ultrasonography and strain sonoelastography. Elastographic scores were determined by a 4-point scoring method. Interventional procedures were performed on all patients after sonographic examinations. The lesions were divided into groups as benign or malignant according to histopathological findings. The difference in elastographic scores between benign and malignant masses was evaluated. Results Among the 39 parotid gland masses, 33 (84.6%) were benign and 6 (15.3%) were malignant tumors with 53.8% (n = 21) of the lesions being on the right side. Pleomorphic adenoma (41%) was the most common neoplasm followed by Warthin tumor (28.2%). The median elastographic score was 2 (range, 1–3) for benign tumors, and it was 3 (range, 2–4) (P = 0.003) for malignant tumors. Median SR was 1.11 (range, 0.26–2.15), and it was 2.75 (range, 1.03–3.54) (P = 0.01) for benign and malignant tumors. In the receiver operating characteristic analysis, the cutoff value of the SR was 2.1, sensitivity was 83.3%, specificity was 97%, positive predictive value was 83.3%, negative predictive value was 97%, and accuracy was 94%. Conclusions There was a statistically significant difference between benign lesions and malignant lesions in both elastography score and SR. It is possible that elastography can improve the noninvasive diagnostic accuracy for certain pathological conditions.

Ultrasonography techniques in the preoperative diagnosis of parotid gland tumors – an updated review of the literature

“…Cortcu et al (2018) managed to differentiate between malignancy and benignity using USE based on strain ratio cutoff value of 2.1 [11]. Encouraging results in the evaluation of parotid tumors with the help of USE have been obtained also by other authors [11,31,39], which shows that this investiga- tion has a potential in differentiating parotid tumors that must be investigated by further studies. USE, especially SE is an operator-dependent investigation, which may explain the large variations between the results of the published studies.…”

“…US can make the differential diagnosis between benign and malignant tumors, can locate the intra-or extra-glandular lesions and is very helpful for the guidance of fine needle aspiration biopsy (FNAB). The technique presents a series of limitations such as: dependence of the operator, lack of standardized sections, low specificity in assessment of parotid tumors histological type, difficulty in evaluating tumors located in the deep parotid lobe or posterior to bone structures [1,5,[7][8][9][10][11][12][13][14].…”

“…At present, the effectiveness of USE, as the only examination technique, is not proven in the differential diagnosis of parotid tumors. Many studies have shown that malignant tumors have higher stiffness values than benign ones and PMAs are in generally stiffer than WTs, but there is a large overlap between these findings [10,11,26,28,33].…”

“…Moreover, adenolymphomas show a great variety of histological structure, which is reflected in the wide range of SWE elasticity modulus of these tumors reported by Huang et al (2018) [44]. However, most authors accept that, in general, malignant tumors are stiffer than benign lesions, and PMAs are stiffer than WTs, but this is not a strong enough criterion to allow the differentiation of parotid tumors [10,11,26,28] Herman et al (2017) obtained encouraging results for differentiating parotid tumors with the help of a coefficient of stiffness variability (CSV) [27]. Cortcu et al (2018) managed to differentiate between malignancy and benignity using USE based on strain ratio cutoff value of 2.1 [11].…”

“…However, most authors accept that, in general, malignant tumors are stiffer than benign lesions, and PMAs are stiffer than WTs, but this is not a strong enough criterion to allow the differentiation of parotid tumors [10,11,26,28] Herman et al (2017) obtained encouraging results for differentiating parotid tumors with the help of a coefficient of stiffness variability (CSV) [27]. Cortcu et al (2018) managed to differentiate between malignancy and benignity using USE based on strain ratio cutoff value of 2.1 [11]. Encouraging results in the evaluation of parotid tumors with the help of USE have been obtained also by other authors [11,31,39], which shows that this investiga- tion has a potential in differentiating parotid tumors that must be investigated by further studies.…”