Characteristic Sonographic Findings of Warthin's Tumor in the Parotid Gland

Purpose. The aim of this study was to define the characteristic sonographic features of Warthin's tumors in the parotid gland, thus enhancing the ability to make a preoperative diagnosis of this disease process. Methods. We retrospectively evaluated the sonograms of Warthin's tumors of the parotid gland that had been confirmed by histopathologic examination of surgically excised specimens from patients treated at our institution over a 2-year period. We recorded the echogenicity, shape, margin, and internal structure of the tumors and categorized them into 2 groups on the basis of size (< 5 cm versus ≥ 5 cm in the largest diameter). Results. Eighteen patients (16 men and 2 women) with a mean age of 57 years (range, 29-82 years) were included in the analysis. One patient had 2 tumors (1 in each parotid gland); the other 17 patients each had only 1 tumor. Our review of the sonographic findings revealed that all 19 tumors were hypoechoic compared with the normal parenchyma of the affected parotid glands. Most of the tumors were ovoid, had well-defined margins, and contained multiple irregular, small, sponge-like anechoic areas. Tumors that were 5 cm or greater in diameter had a higher proportion of cystic content than smaller lesions had and in some cases were composed almost entirely of cystic material. Conclusions. Our evidence suggests that the sonographic appearance of a Warthin's tumor in the parotid gland is distinctive: a well-defined round or ovoid hypoechoic mass containing microcystic anechoic areas. These sonographic features constitute useful criteria in the preoperative diagnosis of Warthin's tumor in the parotid gland, although sonographically guided fine-needle aspiration biopsy may be needed to confirm the diagnosis.