Squamous odontogenic tumour (SOT) was first described in 1975, by Pullon et al. as a rare, benign odontogenic tumor arising in close physical relationship to the dentition from the epithelial rests of Malassez in the periodontal ligament or gingival epithelium. To date, less than 50 cases have been described in the literature. We describe a case of SOT which was histologically misdiagnosed as a metastatic carcinoma of unknown origin. In the discussion and review of the literature that follows, the features of SOT, the differential diagnosis and the appropriate treatment are described.