Intravascular tumour in intra-oral pleomorphic adenomas: a diagnostic and therapeutic dilemma

Aims: Intravascular tumour has been described very rarely in pleomorphic ad enomas. The aim of this study was to establish the frequency of intravascul ar tumour in pleomorphic adenomas arising in minor salivary glands and to d etermine the biological significance of this phenomenon. Methods and results: Representative sections of 67 widely excised pleomorph ic adenomas were examined for the presence of intravascular tumour. Sixty-t wo cases were derived from the palate while the remaining five were from th e cheeks and lips. In instances where intravascular tumour was identified, multiple serial sections were assessed and immunohistochemical stains were performed. None of these cases showed cytological evidence of malignancy. S olid cords of intravascular tumour were present in six palatal tumours (8.9 %) and consisted of plasmacytoid myoepithelial cells permeating muscular wa lled blood vessels and capillaries both within the tumour and capsule. Immu noperoxidase staining confirmed that the intravascular cells were phenotypi cally identical to those of the tumour being S100- and smooth muscle actin (SMA) positive. There is some evidence that; this phenomenon represents tru e vascular invasion although artefactual spillage cannot be excluded. Conclusions: Although the biological significance of intravascular tumour i n pleomorphic adenomas of minor salivary glands remains unknown, the occurr ence of metastatic disease has not been demonstrated nor have aggressive be haviour or recurrences.