Warthin's tumours are the second most common benign parotid tumours in the UK. The World Health Organization states that 5–14 per cent of patients have bilateral Warthin's tumours. This study aimed to: assess the presence of contralateral Warthin's tumours in patients who underwent surgery over the past 16 years at a head and neck unit in England, and perform the first systematic literature review on bilateral Warthin's tumours.

A retrospective analysis was conducted on patients diagnosed with Warthin's tumour based on histology between 2005 and 2020. Additionally, a systematic review (International Prospective Register of Systematic Reviews (‘PROSPERO’) registration number: CRD42022326846) was performed using PubMed and the Cochrane Library.

Among 290 patients diagnosed with Warthin's tumours based on histology following surgery, 24.5 per cent had bilateral Warthin's tumours. The systematic review identified 157 papers, with 14 meeting the inclusion criteria.

This study revealed that 24.5 per cent of patients had bilateral Warthin's tumours, deviating from the suggested range. These findings are of interest to surgeons discussing the disease with patients.