Unreported Cytologic Characteristics of Oncocytes in Warthin's Tumors

Abstract Objective Warthin's tumors can contain markedly atypical or degenerated oncocytes; some have been mistaken for carcinoma or even metastatic carcinoma. To decrease the rate of false cytological diagnosis associated with this tumor, we tried to identify the characteristic cytologic features of Warthin's tumor oncocytes. Materials and Methods The clinical and pathologic features of Warthin's tumor were retrospectively reviewed in 45 cases from 1998 to 2003, in which fine-needle aspirates from 13 patients were examined. Results The male-to-female ratio was 21.5:1, the highest reported to our knowledge. Only 15 patients had a definite smoking history. Diff-Quik stained slides revealed cytologic characteristics not previously described, in which sheets of oncocytes with nuclei containing uniform, eccentric, and single pinpoint nucleoli were arranged in the same plane in all cases. Conclusion These cells with cytologic characteristics that have not been found in other lesions with oncocytes most likely derive from the basal layer of cuboid oncocytes in Warthin's tumor. They may improve the cytological diagnostic accuracy associated with Warthin's tumor.