Relationship between histological features of pleomorphic adenoma in the parotid gland and recurrence after superficial parotidectomy

Background: Pleomorphic adenoma is the most common parotid gland tumour. It is a benign tumour composed of epithelial and myoepithelial cells arranged in various morphological patterns. Thinning or absence of the pseudocapsule and the presence of fingerlike projections of the tumour have been observed in all histological subtypes of pleomorphic adenoma, in particular the myxoid type. It has been suggested that myxoid subtype are involved in the recurrence of disease.