New insights into the nature of Warthin's tumour.

Warthin's tumour is considered heterogeneous as to its pathogenesis with some data supporting a polyclonal origin for the epithelium, implying a non-neoplastic nature. After inconsistent reports, current information from molecular studies suggests that a recurrent t(11;19) and associated CRTC1-MAML2 fusion oncogene characterizes a subset of Warthin's tumours and supports a clonal origin in such cases. CRTC1-MAML2 is also a frequent feature of mucoepidermoid carcinoma. These findings, and the recent reports of Warthin's tumour and co-existent mucoepidermoid carcinoma with common CRTC1-MAML2 expression, provide a morphological and molecular framework for future studies as a basis for a fresh appraisal of the pathogenesis of Warthin's tumour. The underlying molecular basis and the pivotal studies defining such events are discussed.