Scanning electron microscopic study of Warthin's tumor

Three cases of Warthin's tumors were studied with a scanning electron microscope. The free surface of the epithelium was composed mainly of round or ovoid dome-like structures bearing microvilli and apocrine protrusions. Ciliated epithelial cells were detected in 2 of the tumors. The tumor epithelium encircled various amounts of cellular debris resembling degenerate lymphoid cells. A few tiny cystic spaces were also found. Within the lymphoid stroma, tightly packed lymphocytes, a meshwork of reticulum cells and medullary cord-like structures were observed. Our findings support the concept that Warthin's tumors develop from heterotopic salivary gland ducts within pre-existing lymph nodes.