Representative images of hematoxylin and eosin-stained pathologic specimens. Low-grade tumor was composed of epideroid, intermediate, columnar, and goblet cells. The goblet cells were rich in mucin. (A) Low-grade mucoepidermoid carcinoma (MEC), 100×; (B) low-grade MEC, 400×. The cellular component of high-grade tumor was the same as that of low-grade tumor, but squamoid cells were predominant. Cytologic atypia and mitotic activity were more common in high-grade tumor. (C) High-grade MEC, 100×; (D) high-grade MEC, 400×.