Incidence and clinicopathological profile of salivary gland neoplasms: a retrospective study from a tertiary centre

Salivary gland neoplasms are a heterogeneous group of tumours with relatively low global incidence. The incidence of this neoplasm is poorly documented in the African population, and the pattern may differ from the rest of the world. This study aimed to determine the incidence and clinicopathological features of salivary gland neoplasms in an African population. This was a retrospective study of histopathologically confirmed salivary gland neoplasms diagnosed at the University of Maiduguri Teaching Hospital, Nigeria, between January 2003 and December 2021. Data was obtained from histopathology records, request forms, and the departmental cancer registry. Information collected on demographics, tumour site, duration of symptoms and histopathological diagnosis. Non-residents and recurrent cases were excluded. Crude annual incidence rates were estimated using the Borno state population as the denominator. One hundred and fifty-two salivary gland neoplasms were recorded in 148 patients. Four cases of recurrence were excluded. The mean age at diagnosis was 38 ± 16 years, with a male-to-female ratio of 1.2:1. Malignant neoplasms were more prevalent in males, with a ratio of 7.5:1. The age at diagnosis did not differ significantly between benign and malignant neoplasms (p = 0.212). The crude annual incidence rate was 0.15 per 100,000 population. Benign salivary gland neoplasms constituted 77.7% of cases. Pleomorphic adenoma was the most common neoplasm, accounting for 81.7% of benign neoplasms and 63.5% of all neoplasm while Warthin’s tumour was extremely rare (0.7%). Mucoepidermoid carcinoma was the second most common neoplasm overall (10.1%) and the most common malignant salivary gland neoplasm (45.5%). The major salivary glands were the most affected tumour location (69.5%), with the parotid gland being the most frequent site (45.3%). Tumour was extremely rare in the sublingual gland (0.7%). This study revealed a low incidence of salivary gland neoplasms in this African population, with pleomorphic adenoma and mucoepidermoid carcinoma being the most common tumour types. The pattern of distribution, however, deviated from the reported 10:1:1 rule.