Classification of salivary gland tumours--a brief histopathological review

Tumours of the salivary glands display a wide variety of histological appearances, and vary in behaviour from totally benign to high grade and usually fatal malignancies. Over the past 40 years several classification schemes have been proposed, of which the most comprehensive and accurate are those of the Armed Forces Institute of Pathology (AFIP) and the World Health Organization (WHO) which were both revised in 1991. They are readily applicable by practising surgical pathologists, and encompass most of the range of tumours likely to be encountered. If I have a slight preference, it is for the WHO classification which is more concise. This paper briefly discusses each tumour, and highlights the changes from previous classifications, including the proper recognition of several newly described tumours which are distinct clinico-pathological entities. Neither of the new schemes solves every problem, and brief attention is drawn to defects. These are minor, and do not significantly detract from the advantages of both new classifications, which represent a major advance in our ability to understand these often perplexing tumours.