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

Abstract

Intravascular tumour has been described very rarely in pleomorphic adenomas. The aim of this study was to establish the frequency of intravascular tumour in pleomorphic adenomas arising in minor salivary glands and to determine the biological significance of this phenomenon. Representative sections of 67 widely excised pleomorphic adenomas were examined for the presence of intravascular tumour. Sixty-two cases were derived from the palate while the remaining five were from the 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. Solid cords of intravascular tumour were present in six palatal tumours (8.9%) and consisted of plasmacytoid myoepithelial cells permeating muscular walled blood vessels and capillaries both within the tumour and capsule. Immunoperoxidase staining confirmed that the intravascular cells were phenotypically identical to those of the tumour being S100- and smooth muscle actin (SMA) positive. There is some evidence that this phenomenon represents true vascular invasion although artefactual spillage cannot be excluded. Although the biological significance of intravascular tumour in pleomorphic adenomas of minor salivary glands remains unknown, the occurrence of metastatic disease has not been demonstrated nor have aggressive behaviour or recurrences.