Mandibular metastasis from prostate cancer that clinically mimicked osteosarcoma: A case report

Metastatic tumors in the oral cavity are rare, accounting for only 1% of all oral malignancies. The most common site of metastatic tumors in the oral cavity is the mandibular molar region. The primary sites differ between the sexes. Among men, the primary sites are the lung, kidney, liver, and prostate in the order of frequency. Moreover, 11% of jawbone metastases among men originate from the prostate gland. Symptoms differ according to the location of the metastasis; besides, metastases-related imaging findings are nonspecific, making it difficult to reach an accurate diagnosis. Metastatic oral cancer has a poor prognosis; therefore, early diagnosis and treatment are important to improve the survival-rate and quality of life. A 76-year-old male patient was referred to our hospital with complaint of right-sided mandibular swelling and past medical history of adenocarcinoma of the prostate gland. Intraoral examination revealed a hard hemispherical mass on the right mandibular first molar region. Computed tomography showed a well-marginated radiopaque hemisphere mass with a typical sunburst periosteal reaction. Based on the imaging findings, we suspected primary osteosarcoma or metastatic prostate cancer. Histopathological examination of the mandible revealed a glandular structure with atypia similar to that of the primary prostate cancer cells. After prostate specific antigen monitoring therapy, the metastatic cancer did not grow. Metastatic cancers from other organs should be considered in the differential diagnosis of jawbone malignancies because the metastatic cancer might present similarities to the primary cancer in imaging findings, as in the present case that clinically mimicked osteosarcoma.