Oral metastasis as the first indication of undiscovered malignancy at a distant site: A systematic review of 413 cases

This systematic review is the first to provide evidence regarding demographic, clinical, and imaging characteristics, as well as information related to survival, of patients with oral and maxillofacial metastases of occult primary tumors. Case reports, case series, and cross‐sectional studies were included. Ten databases were searched. The risk of bias was assessed using the Joanna Briggs Institute appraisal tools. Overall, 353 articles (413 patients) were included. Statistically significant associations between survival and multiplicity of metastatic foci, and between each of the main primary sites and some features of the oral lesions were observed. Some clinical and imaging characteristics can help dentists in raising diagnostic suspicions and also in relating to plausible primary sites. Early diagnosis of oral and maxillofacial metastases can positively affect the survival rate when they are the only focus of dissemination, conferring an important role on the dentist.