Risk factors for recurrence of pleomorphic adenoma.

Pleomorphic adenoma is the most frequent benign tumor of the salivary glands. It is characterized by a tendency to recur, which is determined by the biological characteristics of the tumor as well as the mode of its treatment. Recurrence of the tumor is associated with a high risk of postoperative facial palsy, risk of subsequent recurrence after revision surgery, and an increased risk of malignant transformation. Knowledge of the recurrence risk factors could allow selection of treatments that minimize the risk. Among the factors in this study the most important are: incomplete excision, intraoperative capsule rupture, myxoid subtype, presence of the satellite nodules and tumor extensions (pseudopodia), lack of the glandular tissue margin and the experience of the surgeon. The possible factors are: the female sex, young age, location and size of the tumor, and the duration of the tumor growth. The technique of tumor enucleation of pleomorphic adenoma carries a high risk of recurrence and should be replaced by parotidectomy. In cases of recurrence the treatment is individually tailored and may: further follow up, limited resection of the tumor, lateral parotidectomy or extended radical parotidectomy with concurrent reconstruction of the facial nerve. The role of radiotherapy is discussed.