Recurrent Benign Salivary Gland Neoplasms.

The most important causes of recurrence of benign pleomorphic adenoma are enucleation with intraoperative spillage and incomplete tumor excision in association with characteristic histologic findings for the lesion (incomplete pseudocapsule and the presence of pseudopodia). Most recurrent pleomorphic adenomas (RPAs) are multinodular. MRI is the imaging method of choice for their assessment. Nerve integrity monitoring may reduce morbidity of RPA surgery. Although treatment of RPA must be individualized, total parotidectomy is generally recommended given the multicentricity of the lesions. However, surgery alone may be inadequate for controlling RPA over the long term. There is growing evidence from retrospective series that postoperative radiotherapy results in significantly better local control. A high percentage of RPAs are incurable. All patients should therefore be informed about the possibility of needing multiple treatment procedures, with possible impairment of facial nerve function, and radiation therapy for RPA. Reappearance of Warthin tumor is a metachronous occurrence of a new focus or residual incomplete excision of all primary multicentric foci of Warthin tumor. Selected cases can be observed. Conservative surgical management can include partial superficial parotidectomy or extracapsular dissection. Not uncommonly, other major and minor salivary gland neoplasms, including myoepithelioma, basal cell adenoma, oncocytoma, canalicular adenoma, cystadenoma, and ductal papilloma, follow an indolent course after surgical resection, with rare cases of recurrence.