Salivary Gland Tumors in Maxillofacial Region: A Retrospective Study of 130 Cases in a Southern Iranian Population

Abstract

Tumors of the salivary glands are uncommon head and neck neoplasia. We conducted a retrospective study of 392 cases over the last 6 years in Shiraz, south of Iran, to investigate the clinicopathological features of these tumors in Iranian population. The age of the patients ranged from 8 to 85 years, with the mean age 44.57 ± 14.65 years and male-to-female (M : F) ratio was 1.02 : 1. For benign tumors, there was a propensity towards females, whereas the malignant tumor was more common in males. The ratio of benign tumors to malignancies was 2.19 : 1. Pleomorphic adenoma (PA) was the most common tumor and accounted for 85% of all benign tumors, followed by Warthin's tumor (8.6%). Of the 125 malignancies, adenoid cystic carcinoma (40%), mucoepidermoid carcinoma (24%) and invasive squamous cell carcinoma (16%) were the most common histological types. Most of the salivary gland tumors (75%) originated from major salivary glands and the remained (25%) originated from minor glands. The parotid gland was the most common site both in benign and malignant tumors. Most of our findings were similar to those in the literature, with some variations. The salivary tumors slightly predominated in males. Adenoid cystic carcinoma and mucoepidermoid carcinoma constituted the most common malignancies.

Epithelial Salivary Gland Tumors in Two Distant Geographical Locations, Finland (Helsinki and Oulu) and Israel (Tel Aviv): A 10-Year Retrospective Comparative Study of 2,218 Cases

“…The most predominant benign SGT is PA followed by Warthin tumor, usually a distant second [9,21,22,24]. This is in line with the present study.…”

“…Furthermore, the incidence of patients with malignant SGTs in the minor salivary glands in TAU (64.5%) was much higher compared to their counterparts in the Finnish centers (Helsinki 27% and Oulu 10.9%). The present results on malignant SGTs in minor salivary glands in TAU is in accordance with the data reported in other 2005 WHO-based studies, in which the frequency of malignant SGTs in the minor glands ranged from about 55% (Sri Lanka and southern Iran) [9,21] to 62% (China) [24]. In the remaining two relevant studies (from the UK and Turkey), the frequency of these tumors was about 40% [22,23], but that figure is still higher than the values from the Finnish centers.…”

“…The 2:1 ratio of benign-to-malignant SGTs in TAU was within the range reported in studies from other regions of the world based on the 2005 WHO classification, including Sri Lanka, 1:1 [9], the UK and China, 2:1 each, [23, 24, respectively], Iran (South), 2.19:1 [21], and Turkey, 3:1 [22]. The results from the Finnish centers were remarkably different, with a benign-to-malignant ratio of 5.4:1 in Helsinki and 7.1:1 in Oulu.…”

“…Earlier single-center studies that were also based on the 2005 WHO classification have reported these two tumors as being the most common malignant SGTs, but the order differed: one study found an equal frequency of these tumors [24], two studies found ACC to be more common [21,22], and the other two studies, including one from the UK, found mucoepidermoid carcinoma to be more common [9,23]. Before 2005, the frequency of mucoepidermoid carcinoma among British patients was much lower than the worldwide range [1], with a predominance of ACC [10,28].…”

“…This was the first study that compared the data on SGTs from two remote geographic locations by examiners who collated data strictly according to the 2005 WHO classification [1]. Other studies similarly reporting epidemiologic data on SGTs provided data accumulated within individual centers and described their results in comparison with studies carried out according to earlier WHO classification systems [9,[21][22][23][24]. The main findings of this research were the differences in the annual incidence of the SGTs (highest in Helsinki, lower in Oulu, and lowest in TAU), in the frequency of the malignant forms of SGT (two-to three-fold higher in TAU than in the Finnish centers), and in the frequency of malignant SGTs in the minor glands versus the parotid gland (higher in TAU compared to the Finnish centers).…”