Tissue that has lost its track: Warthin's tumour.

The origin of cystadenolymphoma (Warthin's tumour) of the parotid gland is unknown. According to the most favoured hypothesis, Warthin's tumour results from the proliferation of salivary gland ductal cells that were entrapped in parotid lymph nodes during embryonal life. If this is correct, and the almost total lack of recurrence and malignant transformation of this lesion lends credence to this view, Warthin's tumour is correctly classified in the group of tumour-like lesions and should not be considered to be a monomorphic adenoma.