Epithelial-myoepithelial carcinoma of the parotid gland: correlation of dynamic magnetic resonance imaging, 18F-fluorodeoxyglucose-positron emission tomography, and pathological findings

Abstract

We encountered two cases of epithelial-myoepithelial carcinoma (EMC), a rare low-grade malignant tumor of the parotid gland. These two EMCs showed similar imaging findings: gradual contrast enhancement on dynamic magnetic resonance imaging (MRI), intense (18)F-fluorodeoxyglucose (FDG) uptake in the solid tumor portion, and little enhancement and little FDG uptake in the hemorrhagic necrotic tumor portion. When a parotid gland tumor shows gradual MRI contrast enhancement and focally intense FDG uptake, EMC should be included in the differential diagnosis.

MRI findings of epithelial–myoepithelial carcinoma of the parotid gland with radiologic–pathologic correlation

“…The frequency of these morphological characteristics was almost identical to the results of the present study. In this study, the signal intensities of the solid components on T1-weighted images were frequently homogeneous, whereas they were often heterogeneous in previously reported cases, especially in larger tumors [4,5,7]. The common signal intensities and enhancement patterns of the solid components in our and previous cases included hypo-to isointensity on T1-weighted images, heterogeneous iso-to hyperintensity on T2-weighted images, and heterogeneous enhancement on contrast-enhanced imaging [4][5][6][7].…”

“…The histological differential diagnosis of EMCs includes all other salivary gland neoplasms, such as pleomorphic adenoma, myoepithelial carcinoma, adenoid cystic carcinoma, acinic cell carcinoma, mucoepidermoid carcinoma, and metastatic renal cell carcinoma [8]. Several previous case reports described the CT and MRI findings of EMCs of the parotid gland [4][5][6][7]. Based on these case reports, EMCs appear as either predominantly solid lesions [4,5,7] or as predominantly cystic lesions [6].…”

“…Based on these case reports, EMCs appear as either predominantly solid lesions [4,5,7] or as predominantly cystic lesions [6]. The interface between the tumor and parotid parenchyma was clearly defined in all cases [4][5][6][7]. A multinodular appearance with internal septa on T2-weighted images was observed in more than half of previous cases [4,5].…”

“…Currently, histopathological examination is required for the diagnosis of EMC and the role of imaging is limited to the evaluation of tumor localization, extension, and metastasis. Although CT and MRI findings of EMCs of the parotid gland have been described in several case reports [4][5][6][7], to the best of the authors' knowledge, no previous studies have summarized the MRI features of EMC. Therefore, this study was performed to determine the…”

A Rare Case of Clear Cell Carcinoma of the Parotid Gland in Iran

“…In studies that used ultrasound in initial assessments, MRI and CT scans were used for more accurate assessments (10). MRI and CT scans are used for comprehensive assessments of large tumors and to determine the possible relationship of lesions in parotid glands with surrounding vessels to enable grading, access for resection, and draw up a treatment plan for neck dissection (10,11). The higher resolution and contrast of MRI make it more suitable than CT scans for the assessment of parotid tumors (10).…”