MRI and CT imaging characteristics of myoepithelioma of the parotid gland.
BACKGROUND
Myoepithelioma is a rare tumor of the salivary gland and only few reports have focused on its imaging characteristics.


OBJECTIVE
To characterize the magnetic resonance imaging (MRI) and computed tomography (CT) characteristics of myoepithelioma of the parotid gland.


METHODS
We retrospectively analyzed the MRI and CT findings of nine patients with myoepithelioma in the parotid gland as demonstrated by pathologic analysis. The MRI and CT findings were analyzed regarding the tumor position, size, marginal morphology, and degree and patterns of enhancement.


RESULTS
Unilocular and multilocular tumors were found in seven cases (7/9, 77.8%) and two cases (2/9, 22.2%), respectively. Most of the tumors were located in the superficial lobe (6/9, 66.7%) and abutted the capsule of the parotid gland (7/9, 77.8%). Six of the seven unilocular tumors were round. Most of the tumors displayed smooth contours (6/9, 66.7%) and well-defined margins (5/9, 55.6%). Four of five tumors (80%) display the capsule on T2-weighted (T2W) and contrast-enhanced T1-weighted (T1W) imaging. All five examined tumors exhibited homogeneous intermediate signal intensity on T1W imaging and high signal intensity on T2W imaging. On contrast-enhanced T1W imaging, the tumors displayed homogeneous (n = 4) or heterogeneous (n = 1) moderate to marked contrast enhancement. Based on the enhanced CT scans, four tumors exhibited moderate homogeneous (n = 2) or heterogeneous (n = 2) contrast enhancement.


CONCLUSIONS
Myoepitheliomas are characterized as small, unilocular, round tumors with smooth contours that are located in the superficial lobe and abut the capsule of the parotid gland, display the capsule on T2W and contrast-enhanced T1W imaging, and exhibit homogeneous signal intensities or densities based on MRI and CT.
Department of Radiology, Fudan University Shanghai Cancer Center, Shanghai, PR China Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, PR China dingjh99@163.com.
Jianhui
J
Ding
Department of Radiology, Fudan University Shanghai Cancer Center, Shanghai, PR China Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, PR China.
Wei
W
Wang
Department of Radiology, Fudan University Shanghai Cancer Center, Shanghai, PR China Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, PR China.
Weijun
W
Peng
Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, PR China Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, PR China.
Xiaoyan
X
Zhou
Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, PR China Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, PR China.
Tongzhen
T
Chen
D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009208:Myoepithelioma / Q000000981:diagnostic imaging* / Q000473:pathology; D010307:Parotid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D019786:Gadolinium DTPA
Salivary gland; computed tomography (CT); magnetic resonance imaging (MRI); myoepithelioma