Mucoepidermoid Carcinoma : High-grade
High-grade mucoepidermoid carcinomas are solid tumors with no cyst formation. They are composed predominantly of solid sheets and clusters of epidermoid and intermediate cells with cytologic atypia. They have prominent nucleoli and show brisk mitotic activity. They may focally resemble moderately-differentiated squamous cell carcinoma; however, extensive keratinization, large prominent keratin pearls, and intercellular bridges are not common. There may be only individual cell keratinization or formation of small keratin pearls. This high-grade mucoepidermoid carcinoma from an elderly male was a recurrent tumor in the submandibular region that arose several years after the initial resection. There were scattered mucicarmine-positive cells throughout the tumor.