[Epidemiology of non-malignant salivary gland tumours based on 675 cases].

Neoplasm of salivary glands constitutes about 3% of all tumours of head and neck. Within the category we can differentiate tumours of a very different histological structure. What lies behind such great differences in the changes within the salivary glands is complex embryogenesis of the glands. About 80% of all tumours of salivary glands is located in parotid gland, from 10 to 20% - in submandibular gland and several percent in sublingual and small salivary gland. This work aims at the assessment of the frequency of occurrence of non-malignant neoplasm in parotid and submandibular gland based on the material collected at the ENT Department of the Medical University in Poznan in the years 1995-2006. In the 12-year period, 778 patients in total suffered from tumours of large salivary glands. The number of non-malignant neoplasm was 675, and the number of malignant neoplasm was 103. With regard to paroid glands, 586 non-malignant tumours and 82 malignant tumours were identified, with regard to submandibular glands the numbers were respectively: 89 and 21. Main aim of this work has been achieved through the execution of partial steps: the analysis of the trends in occurrence of non-malignant neoplasm in the 12-year period, the analysis of the epidemiological differences: sex, age, place of residence - town or country, duration of symptoms, diameter of the tumour at the time the patient reported for treatment, histological structures that were carried on the basis of the comparison of data collected in the two periods of time: period I--the years 1995-2000 and period II--the years 2001-2006. The frequency of operations on non-malignant tumours of salivary glands (as compared to the total number of operations) was 4.11% in the first period and 4.18% in the second. In both periods the most frequent benign tumour was the mixed tumour (54.9% of all tumours) and constituted 60% and 54% of all tumours in the respective periods analyzed. The next most frequently occurring tumour was Warthin's tumour, identified in 31.2% of the patients, in 23% in period I and 35% in period II. Duration of the symptoms, ranged from 1 month to 20 years, 14 months on average, yet in 263 cases the tumour has been developing developed for over a year. The diameter of the non-malignant tumours undergoing operation ranged from 1 cm to 8 cm, with the average being 3 cm. It was 3 cm with regard to the most frequently occurring tumours: adenoma polymorphum, adenoma monomorphum and cystadenolymphoma.