Introduction 1 2 3 4 5 7 5 7 8 12 13 18 The present study was undertaken to address these important issues based on a follow-up period of up to 20 years. Here, we present our findings and review some of the more recent literature. Materials and methods A retrospective analysis of the charts of patients treated for benign parotid neoplasm between 1983 and 2004 was performed to identify those patients operated on for RPA. We collected information on patient demographics and clinical history, clinical features of the lesions, diagnostic work-up, the type of surgery, operative findings, facial nerve management, and adjuvant treatment. The study analyzed the prevalence of surgical complications and new recurrences. Statistical analysis was performed using the SPSS statistical package. Tumor recurrence rate was estimated by the Kaplan–Meier method: the entry point was the date of surgery for a recurrent tumor seen for the first time in our department, and the end point was the date of a new recurrence or the date of last consultation for censored observations. The prognostic value of certain categorical variables (age, gender, number of previous operations, type of previous operation, lobe of origin, type of surgery performed for RPA, maximum diameter, facial nerve resection, presence of a pseudocapsule at the surgical margins, rupture of the pseudocapsule, number of neoplastic nodules, postoperative radiotherapy) was tested by univariate analysis using the log rank test. Results 1 Table 1 Summary of clinical history of patients treated for the first time at the Department of Otolaryngology of the University of Brescia for RPA of the parotid gland Previous recurrences   One 63.6% (21)   Two  18.2% (6)   Three  12.1% (4)   Four  6.1% (2) Median time to recurrence   First recurrence (33)  6 years (range 1–23)   Second recurrence (12)  5 years (range 2–28)   Third recurrence (6)  5.5 years (range 3–19)   Fourth recurrence (2)  8 years (both patients) Last operation   Subtotal parotidectomy  33.3% (11)   Local excision  33.3% (11)   Superficial parotidectomy  21.2% (7)   Not reported  12.1% (4) Number of patients in parentheses Ultrasonography was the most frequently used diagnostic tool (23 patients, 69.7%), followed by fine needle aspiration biopsy in 21 (63.6%) patients, magnetic resonance imaging in 14 (42.4%), computed tomography in 3 (9.1%), and sialography in 2 (6.1%). The different types of diagnostic procedures employed reflect the multi-decade period analyzed. At present, after ultrasonography, which is routinely adopted for follow-up, magnetic resonance imaging is used to delineate the extension of the recurrent lesions. In 12 (36.4%) patients, the lesion involved the superficial lobe of the parotid gland, in 9 (27.3%) both lobes, and in 12 (36.4%) only the deep lobe was involved. In 5 (15.2%) patients the lesion also extended to the parapharyngeal space. Information on multinodularity of the lesion could be obtained for 31 patients: multiple lesions were observed in 24 (77.4%) of them. 2 3 Table 2 Surgical treatment for RPA of the parotid gland at the Department of Otolaryngology of the University of Brescia Total or extended total parotidectomy  48.5% (16) Superficial parotidectomy  30.3% (10) Local excision  21.2% (7) Partial or total facial nerve resection 30.3% (10) Number of patients in parentheses Table 3 Postoperative complications of patients treated for RPA of the parotid gland at the Department of Otolaryngology of the University of Brescia Frey syndrome  43.7% (14/32) Temporary paresis of a branch or of the entire facial nerve 30.4% (7/23) Definitive paralysis of the marginal mandibular branch of the facial nerve 4.3% (1/23) Salivary fistula 3.0% (1/33) Keloid 3.0% (1/33) 4 1 5 5 Table 4 Distribution of the new recurrences after treatment for RPA of the parotid gland at the Department of Otolaryngology of the University of Brescia (No. = 11; 33.3%) Variable  % P Age ≤30 years (3/10) 30.0 1 >30 years (8/23) 34.8 Gender Female (4/18) 22.2 0.1 Male (7/15) 46.7 Number of previous operations 1 (7/21) 33.3 1 >1 (4/12) 33.3 Type of previous operations Enucleation (2/11) 18.2 0.2 Parotidectomy (8/18) 44.4 Lobe of origin Superficial (5/21) 23.8 0.1 Deep (6/12) 50.0 Intervention performed Parotidectomy (6/26) 23.1 0.02 Other (5/7) 71.4 Maximum diameter ≤2 cm (7/16) 43.8 0.3 >2 cm (3/15) 20.0 Facial nerve resection No (7/23) 30.4 0.7 Yes (4/10) 40.0 Involvement of surgical margins No (8/23) 34.8 0.5 Yes (2/8) 25.0 Capsular rupture No (6/23) 26.1 0.2 Yes (4/8) 50.0 Multiple nodules No (0/7) 0 0.04 Yes (10/24) 41.7 Postoperative radiotherapy No (9/24) 37.5 0.3 Yes (2/9) 22.2 Fig. 1 Estimated recurrence rate after treatment for recurrent pleomorphic adenoma of the parotid gland at the Department of Otolaryngology of the University of Brescia (Kaplan–Meier method)  Table 5 Estimated tumor recurrence rates after treatment for RPA of the parotid gland at the Department of Otolaryngology of the University of Brescia (log-rank test) Variable  Estimated tumor recurrence rates (%) P 5-year 10-year 15-year 20-year Age ≤30 years (10) 12.5 ± 11.7 41.7 ± 18.6 – – 0.8 > 30 years (23) 14.7 ± 7.9 26.9 ± 10.5 42.4 ± 12.8 56.8 ± 15.7 Gender Female (18) 13.4 ± 9.0 30.7 ± 13.1 30.7 ± 13.1 30.7 ± 13.1 0.4 Male (15) 14.3 ± 9.4 30.7 ± 13.0 56.7 ± 15.1 71.1 ± 16.3 Number of previous operations 1 (21) 11.8 ± 7.9 25.4 ± 11.1 45.6 ± 14.7 63.7 ± 17.8 0.9 >1 (12) 18.5 ± 11.9 41.8 ± 16.3 41.8 ± 16.3 41.8 ± 16.3 Type of last previous operation Enucleation (11) 9.1 ± 8.7 24.2 ± 15.6 24.2 ± 15.6 24.2 ± 15.6 0.2 Parotidectomy (18) 20.0 ± 10.3 45.1 ± 14.0 58.9 ± 15.9 100 Lobe of origin Superficial (21) 0 13.8 ± 9.1 32.1 ± 13.6 54.8 ± 20.6 0.07 Deep (12) 35.8 ± 14.4 59.9 ± 16.4 59.9 ± 16.4 59.9 ± 16.4 Intervention performed Parotidectomy (26) 5.3 ± 5.1 16.4 ± 8.7 30.5 ± 11.7 47.9 ± 17.4 0.001 Other (7) 42.9 ± 18.7 – – – Maximum diameter ≤2 cm (16) 19.6 ± 10.2 26.9 ± 11.6 44.3 ± 14.0 72.2 ± 20.9 0.4 >2 cm (15) 10.0 ± 9.5 32.5 ± 15.5 32.5 ± 15.5 32.5 ± 15.5 Facial nerve resection No (23) 9.4 ± 6.3 27.2 ± 10.6 35.3 ± 12.1 51.4 ± 16.7 0.4 Yes (10) 25.0 ± 15.3 40.0 ± 18.2 – – Involvement of surgical margins No (23) 14.0 ± 7.5 24.7 ± 9.7 37.9 ± 11.7 53.4 ± 16.0 0.3 Yes (8) 25.0 ± 21.7 62.5 ± 28.6 – – Capsular rupture No (23) 16.4 ± 8.8 38.7 ± 12.8 38.7 ± 12.8 38.7 ± 12.8 0.8 Yes (8) 12.5 ± 11.7 12.5 ± 11.7 40.0 ± 18.2 100 Multiple nodules No (7) 0 0 0 0 0.02 Yes (24) 19.6 ± 8.9 36.8 ± 11.2 53.2 ± 13.4 100 Postoperative radiotherapy No (24) 14.2 ± 7.7 34.3 ± 11.8 48.9 ± 12.9 65.9 ± 16.4 0.3 Yes (9) 12.5 ± 11.6 25.0 ± 15.3 25.0 ± 15.3 25.0 ± 15.3 Discussion 7 5 7 6 8 9 11 12 14 17 19 24 10 13 18 25 13 18 4 24 26 26 4 2 4 24 2 4 24 19 23 10 14 6 8 15 17 18 20 23 25 9 11 13 15 18 23 25 24 2 4 18 9 13 16 17 24 27 17 6 9 13 16 19 20 27 9 13 16 17 27 24 22 8 10 12 15 17 20 23 25 12 25 18 1 5 13 18 13 13 14 15 15 16 17 18 Conclusion The management of RPA is a major challenge for the clinician. RPAs, particularly multinodular tumors, are prone to new recurrences especially when treatment of the initial tumor is performed according to currently accepted standards. MRI is considered to be the best tool to delineate the extension of the lesion, although it can miss microscopic nodules. Options for management include pure observation, not only for the elderly or infirm, but also in cases of small lesions until they begin to grow. When surgery is elected, it should be tailored to the single patient, because even if on one side a limited local excision is considered acceptable, on the other side a total or extended parotidectomy may be inadequate to control an RPA adjacent to the nerve. In these cases, facial nerve resection and reconstruction must also be considered and discussed with the patient in the preoperative counseling. Postoperative radiotherapy is an option, particularly for older patients for whom the risk of inducing other malignancies is considered to be low. Follow-up for patients treated for RPA should be done with regular ultrasonography for the lifetime of the patient and with magnetic resonance in selected cases with deep lobe or parapharyngeal involvement. All patients should be informed about the possibility of the need for multiple treatment procedures.