Retrospective study of 124 cases of salivary gland tumors and literature review

Abstract

Background: Salivary gland tumors are a rare and morphologically diverse group of lesions and their frequency is still unknown in several parts of the world. The knowledge of its population characteristics contributes to a better understanding of its etiopathogenesis. Objectives: This study investigated the frequency of salivary gland tumors in a region of southern Brazil and compared these data in a literature review.

Material and methods: A retrospective study was conducted of salivary gland tumors diagnosed at two pathology centers from 1995 to 2016. Patient age and gender, tumor site and frequency, histopathological diagnosis, and symptomatology were evaluated. Chi-squared tests were used to assess the associations between variables. To compare our data, we also conducted a literature review of publications in the PubMed and LILACS databases of retrospective studies of salivary gland tumors.

Results: A total of 124 salivary gland tumor cases was identified, 81 (65.3%) of which were classified as benign and 43 (34.6%) as malignant. Most tumors occurred in the parotid gland (57.2%). Pleomorphic adenoma was the most common tumor (59.6%), followed by adenocarcinoma not otherwise specified (8.8%). The tumors occurred more often in women (54.8%) than in men (45.2%). Malignant tumors were associated with pain in 31.4% of cases (p<0.05). The literature review included 35 articles from different countries. Women were most affected, with a mean age of 41.7 years. The most common benign tumor was pleomorphic adenoma (48.2%) and the most common malignant tumor was mucoepidermoid carcinoma (8.7%).

Conclusions: The results of the present study showed that salivary gland tumors are rare. The parotid gland is the most common location and pleomorphic adenoma are the most frequent lesions. The malignant tumors presented as several histological types and the incidence was variable globally. Key words:Salivary gland neoplasms, salivary gland diseases, oral surgery, epidemiology.

Figure 1

A: Pleomorphic adenoma: (H&E 100x) Tumor composed of epithelial and myoepithelial cells arranged in diverse patterns, surrounded by a fibrous capsule. B: Pleomorphic adenoma: (H&E 400x) Plasmacytoid myoepithelial cells and ductal structures in a fibrous stroma. C: Adenocarcinoma NOS: (H&E 200x) Several cell types, including clear, mucous, and epidermoid cells arranged in different shapes, showing intense cellular and nuclear pleomorphisms. D: Cystic adenoid carcinoma: (H&E 200x) Islands of basaloid epithelial cells containing multiple cylindrical spaces such as cystic spaces filled with basophilic mucoid material. E: Mucoepidermoid carcinoma: (H&E 200x) Nests of pleomorphic epidermoid cells and mucous-producing cells surrounding cystic spaces. F: Carcinoma ex-pleomorphic adenoma: (H&E 200x) Epithelial cells with pleomorphic nuclei arranged in the islands and ductal structures associated with suggestive pleomorphic adenoma areas.