Relative Proportions of Stromal to Cellular Components of Pleomorphic Adenomas

Abstract

Determination With Shear Wave Elastography easurement of tissue stiffness by sonography is a relatively new and expanding field of research. The principle theory in elastography is that malignant tumors are stiffer than benign ones. Preliminary evidence suggests that elastographic techniques may have a discriminatory value for detecting malignancies in the breast and thyroid gland. 1-3 However, elasticity imaging (both by qualitative and quantitative elastographic methods) is not definitive in distinguishing benign from malignant lesions in the salivary glands. [4][5][6][7][8][9] In particular, the appearance of pleomorphic adenomas Deniz Cebi Olgun, MD, Fatih Kantarci, MD, Umit Taskin, MD, Fahrettin Kilic, MD, Mehmet Faruk Oktay, Serdar Altinay, MD, Nuray Kepil, MD, Ibrahim Adaletli, MD, Mehmet Ada, MD, Ismail Mihmanli, MD Received July 2, 2013, Objectives-The purpose of this study was to evaluate whether the relative proportions of stromal to cellular components of pleomorphic adenomas have an effect on the shear elastic modulus determined by shear wave elastography (SWE).Methods-This study was approved by the Ethics Committee of our institution and performed between September 2011 and December 2012. Thirty-five patients who underwent surgery for a parotid mass were included in the study. The maximum shear elastic modulus of the mass was measured by SWE. Pleomorphic adenomas were histopathologically subdivided into stroma-poor, intermediate-stroma, and stroma-rich tumors based on the relative proportion of stromal to cellular components.Results-The maximum shear elastic modulus values of the pleomorphic adenomas ranged from 12.6 to 291.9 kPa (mean ± SD, 120.9 ± 92.8 kPa). The Friedman test revealed a statistically significant relationship between the stromal amount and maximum shear elastic modulus (P < .001). Stroma-poor adenomas (mean, 32.3 ± 27.7 kPa; range, 12.6-81.1 kPa) were softer on SWE than stroma-rich adenomas (mean, 174.1 ± 48.4 kPa; range, 92.7-217.2 kPa; P = .009). No such significant difference was detected between stroma-poor and intermediate-stroma tumors (mean, 146.3 ± 106.1 kPa; range, 19.1-291.9 kPa; P = .062) or between intermediate-stroma and stroma-rich tumors (P = .465).Conclusions-Shear wave elastography depicts pleomorphic adenomas with a variable appearance, which is due to the relative proportions of stromal to cellular contents in the tumors.

Differential Diagnosis of Parotid Gland Tumors: Role of Shear Wave Elastography

“…This is caused by very variable histoarchitecture of salivary gland tumors which results in considerable variance in stiffness found both in our study ( Figure 3 ) and previously published papers [ 4 , 13 ]. Another complicating factor is the extremely wide range of elastographic values in pleomorphic adenomas (stiffness maxima may vary from 12.6 to 291.3 kPa) [ 6 ]. Due to its myxochondroid component, the stiffness of this benign lesion may be very high, overlapping that of malignant tumors.…”

“…Therefore, the statistical comparison between the two groups was not possible [ 13 ]. Olgun et al did not include any malignant tumor in their study at all [ 6 ]. In a group of 10 carcinomas, Wierzbicka et al reported the sensitivity of conventional ultrasound in differentiation of benign from malignant lesions to be 93.8% and 62.5%, respectively.…”

“…So far, it is well established in breast and thyroid gland lesions [ 11 , 12 ]. We are aware of three studies only that report the use of SWE in salivary glands [ 6 , 8 , 13 ]. The aim of this study was to calculate the sensitivity and specificity of conventional US and SWE parameters.…”

Is There Any Difference Between Seminomas and Nonseminomatous Germ Cell Tumors on Shear Wave Elastography?

“…Notably, SWE effectively differentiated seminomas from nonseminomatous germ cell tumors. Recently, Olgun et al 13 used SWE to classify pleomorphic adenomas in terms of their stromal and cellular components. We thus sought to build on their work.…”

Utility of Real-Time Shear Wave Elastography in the Assessment of Testicular Torsion

“…Precompression is a substantial factor in obtaining accurate results with elastography so that the operator should place the transducer onto the skin surface with light contact using ample coupling gel and keeping the transducer stationary during acquisitions in order to reduce compression on the structures[ 29 , 33 – 34 ]. SWE image was displayed along with the gray-scale ultrasound (US).…”