Minor Salivary Gland Tumors: A Retrospective Study of 37 Cases

Abstract

Salivary gland tumors represent 2% - 6.5% of all head and neck tumors. Since salivary gland tumors have various clinical features and histological types, it is often difficult to diagnose and treat them. The aim of this study was to conduct a retrospective clinical-statistical analysis of 37 minor salivary gland tumors (MSGTs) treated in the Department of Oral Surgery at Nihon University School of Dentistry at Matsudo over a 16-year period. The frequencies and distributions of sex, age, occurrence site, preoperative examination (fine needle cytology and/or biopsy), treatment, and prognosis of the tumors were analyzed and compared with previous reports. The average age at diagnosis was 58.1 years (range 22 - 91 years). The peak occurrence of tumors was in the sixties (10 cases, 27.0%), followed by the forties (8 cases, 21.6%) and the seventies (7 cases, 18.9%). The average age of patients with benign tumors was 56.8 years (range 22 - 91 years). For malignant tumors, the average age was 61.7 years (range 42 - 81 years). The male-female ratio was 1:2.1 for all minor salivary gland tumors, 1:2.4 for benign tumors, and 1.5:1 for malignant tumors. There were 27 (73.0%) benign and 10 (27.0%) malignant tumors. Pleomorphic adenoma (PA) was the most common tumor (24 (64.9%) cases). Most salivary gland tumors originated from the palate (21 cases, 56.8%); the second most common site was the buccal mucosa (14 cases, 37.8%). For most patients, an intraoral mass was the primary presentation, and the second most common symptom was swelling. Surgical treatment was performed for all cases, both benign and malignant tumors. There was one case of local recurrence of PA, as well as one of multiple lung metastases after surgery for adenoid cystic carcinoma. Diagnosis and treatment of MSGTs are often delayed because the patients have few symptoms, and it is difficult to distinguish benign from malignant tumors. More cases need to be examined in the future, and the diagnostic accuracy of imaging and histopathological diagnosis needs to be improved.