腮腺肌上皮瘤课件

1、Myoepithelioma of the Parotid Gland: CT Imaging findingsHuanhuan Su2012-02-06ME is a benign salivary gland tumor composed almost exclusively of sheets, islands, or cords of cells with myoepithelial differentiationSpindle cells, plasmacytoid cells, epithelioid cells, clear cell patterns.Other termsmy

2、oepithelial adenoma benign myoepithelial tumor IntroductionBenign adenomas account for 65.5% of salivary gland tumors.MEs were recognized as a histologically distinct entity in 1991 by the World Health Organization.IntroductionMEs account for 1.5% of all of the tumors in the major and minor salivary

3、 glands,and 40% arise in the parotid glands.Minor salivary glands follow in frequency, especially in the palate (21%).IntroductionThe age of patients with ME ranges from 9 to 85 years, with an average of 44 years and the peak age of occurrence in the third decade.It typically presents as a solitary,

4、 slowly growing, otherwise asymptomatic mass.MEs are less prone to recur than pleomorphic adenomas.IntroductionCT imaging features and pathologyCT imaging features homogenous enhancement (Fig 1) inhomogeneous enhancement with enhancing nodules, the presence of cystic areas (Fig 2), slitlike-shaped a

5、rea (Fig 3), and linear bands (Fig 4).smooth or lobulated contours located in the superficial lobe of the parotid gland, abutted the capsule of the gland CT imaging features and pathology A 56-year-old woman with ME.A, Contrast-enhanced multiplanar reformatted coronal CT scan shows a well-defined ma

6、ss in the tail of the right parotid gland with inhomogeneous enhancement (white arrow). Note the slitlike-shaped nonenhancing area (small black arrow). B,Microscopic examination (HE40) shows that there are hemorrhage (stars) and tumor cells (arrow) in the stroma.CT imaging features and pathologyA 54

7、-year-old man with ME. A, Precontrast axial CT scan shows a well-defined mass with a lobulated margin in the superficial lobe of the right parotid gland abutted on the capsule of the gland (arrow). B, Contrast-enhanced axial CT scan shows the mass with inhomogeneous enhancement. It contains enhancin

8、g nodules (arrows) and nonenhancing linear band (arrowheads). C, Microscopic examination (HE2)shows the stroma (black asterisks) and epithelioid nests(arrows) with a lot of vessels. D, Microscopic examination (HE100)shows that the nest is composed of plasmacytoid. epithelial nest with plentiful bloo

9、d vessels either collagenous or mucoid stromastroma surrounding hemorrhage nonenhancinglinear bandsslitlike-shapednonenhancing areaEnhancing nodulesCT imaging features and pathology spindle cell type withfibrous stroma Cellular myoepitheliomas with fibrous stromahave more vascularity and enhancement

10、 than those with rich myxoid stroma. intenseenhancement Various enhancement patternswell circumscribedenhancing mass lesions with smooth or lobulated marginslocated chiefly in the superficial lobe and abutted on the capsule of the glandenhancing nodulesnonenhancing areas of linear bands, slitlike-sh

11、aped or of cystic configurationConclusionsDifferential diagnoses Pleomorphicadenomas Relatively large cystic changes are more frequent in MEs than in pleomorphic adenomashappen in superficial and/or deep lobes of the parotid and not often abut the capsule of the glandlittle or no enhancement in the immediate postcontrast scan but manifest increased enhancement in the delayed scan.Differential diagnosesWarthinstumors more common in elderly men than in women and can be multifocal and bilateral in 10%15% of pat