Oral and maxillofacial pain as the first sign of metastasis of an occult primary tumour:A fifteen-year retrospective study

BACKGROUND Metastatic adenocarcinoma of the jaw(MAJ)is a rare disease that accounts for 1%-3%of all oral and maxillofacial malignant tumours.Oral and maxillofacial pain may be the first symptom of metastatic spread of an occult primary tumour.Therefore,early identification of oral and maxillofacial pain by dental professionals is critical.AIM To explore the clinical and computerized tomography(CT)features of MAJ with oral and maxillofacial pain as the first symptom.METHODS The medical records of all patients who were treated in our hospital between January 2006 and February 2020,and diagnosed with MAJ with oral and maxillofacial pain as the first symptom,were reviewed retrospectively.Clinical data were collected on age,sex,medical history,clinical manifestations,site of metastasis,and site of the primary lesion.CT features were analysed in detail,and a radiological classification scheme comprising five types:Osteolytic,osteoblastic,mixed,cystic,and alveolar bone resorption was proposed.RESULTS The primary sites of MAJ were the lungs(n=6),liver(n=4),kidneys(n=2),prostate(n=1),and gastric cardia(n=1).Five tumours were classified as the osteolytic type,all with a permeative margin(100%,P<0.05),and three were classified as the mixed type,mostly with a moth-eaten margin(80%,P<0.05).The cystic(n=3)and alveolar bone resorption(n=1)types had geographic margins,and the osteoblastic type(n=1)had sclerotic margins.Moreover,nine tumours showed periosteal reaction and five showed a localised soft tissue mass,while the occurrence of jaw expansion was relatively rare.CONCLUSION MAJ has complex clinical and CT features.Oral and maxillofacial pain may be the first sign of a primary tumour affecting other sites.