Fig. 1Cytologic and histologic findings of pleomorphic adenoma case misdiagnosed as mucoepidermoid carcinoma. The fine needle aspiration cytology smear shows a few cellular clusters with squamoid features (A), and histologically squamous metaplasia and microcystic changes are observed (B).
Fig. 2Cytologic findings of pleomorphic adenoma cases misdiagnosed as an inflammatory condition. The fine needle aspiration cytology smear displays low cellularity with a lack of three cellular components such as epithelial, myoepithelial and stromal origin (A), and the nuclear debris in the necrotic background that are misinterpreted as inflammatory cells (B).
Fig. 3Cytologic findings of the Warthin's tumor cases showing diagnostic discrepancies. The typical cytologic features of Warthin's tumor consist of oncocytic cell clusters and mature lymphocytes in the necrotic background (A). A case, diagnosed as simply benign, shows degenerated or squamoid cells mixed with inflammatory cells instead of oncocytic cell clusters (B). Another Warthin's tumor case with cystic change reveals cell debris in the necrotic background (C), and scanty spindled or squamoid cells mixed with cell debris (D).
Table 1Causes of diagnostic discrepancy in the 61 cases of pleomorphic adenoma
Table 2Causes of diagnostic discrepancy in the 12 cases of Warthin's tumors