Clinical approach and treatment of benign and malignant parotid masses, personal experience

Abstract

Parotid gland tumours account for 80% of all salivary gland neoplasms, 20% of these are malignant, but in daily clinical practice most parotid masses are operated on before obtaining the final histological diagnosis. This clinical setting further complicates the critical point of parotid surgery, which is the management of the facial nerve. In the present study, data were evaluated referring to 540 patients who underwent parotidectomy for a mass which was discovered to be a benign (470 cases) or a malignant (70 cases) neoplasm, between November 1994 and December 2007, at our Institution. The most significant single parameter in this series of malignancies regarding disease specific survival was the clinical involvement of the facial nerve at diagnosis (p = 0.006). Also for this reason, as there is no evidence that liberal VIIth nerve sacrifice improves prognosis, when it is not clinically involved, every attempt is made to dissect and preserve it. At present, the most complicated situation concerning nerve preservation may be, on the other hand, recurrence of a benign tumour, in particular pleomorphic adenoma, which, in our series, has a higher incidence (8.3%) of permanent facial dysfunction, than surgery with nerve preservation for malignancy (3.7%).

Keywords: Facial nerve; Parotid tumours; Prognostic factors.

Fig. 1.

In the "benign" group age follows a bimodal Gaussian distribution with a peak in the first half of the seventh decade and another in the second half of the fifth decade (Fig. 1A). In the group of malignancies, age follows an unimodal Gaussian distribution with the peak in the seventh decade (Fig. 1B).

Fig. 2.

Distribution of histotypes in the 470 benign parotid neoplasms.

Fig. 3.

In the salivary histotypes, overall survival in the present series was 85% at 2 years and 72% at 5 years (A); disease specific survival was 93% at 2 years and 89% at 5 years (B).

Fig. 4.

The most significant clinical parameter in the present series was involvement of the facial nerve at diagnosis (p = 0.006 at Log-Rank), associated with a 66% 5-year disease specific survival, versus a 91% 5-year disease specific survival for patients with normal nerve function at diagnosis.

Fig. 5.

A relatively small volume (A, B) malignancy (SCC) of the parotid gland in a 25-year-old female, with a marked static and dynamic facial nerve dysfunction (C) (Grade V according to the House-Brackmann classification). Total parotidectomy, was performed together with modified radical neck dissection (pT4, N2b) and reconstruction with a sural nerve interposition between the proximal and distal (buccal and ocular) stumps (D, E, F, G). The patient then underwent adjuvant radiotherapy. Functional recovery was not successful, as the residual deficit was Grade IV-V as well (H, I).