2019 Volume 82 Issue 1 Pages 12-18
Because approximately 1% of all malignant tumors, metastasize to the oral region, it is necessary to be aware of each patient's symptoms and medical history, and to obtain images as necessary. This is a report of image findings and the clinical course of a metastatic colon carcinoma to the mandible under perioperative oral management. A 70‐year‐old man presented with the chief complaint of a swollen and painful left mandible. The patient had a history of an operation for colon carcinoma and post‐operative chemoradiotherapy two years before. Locoregional and lymph node metastasis were suspected by FDG‐PET/CT. No bone destruction of the left mandible was observed on panoramic radiography at the first visit. Bone algorithm computed tomography (CT) revealed a periosteal lesion in the left mandible. The patient was diagnosed as having osteomyelitis of the left mandible. After two months, the swelling and pain had progressed considerably, and a second CT and the first magnetic resonance image (MRI) were performed. An axial CT image showed a low‐density area compared with the muscles within the left masseter space. An axial T1‐weighted image revealed a homogeneous mass with intermediate signal intensity, and an axial fat‐suppressed T2‐weighted image revealed a heterogeneous hyperintense mass in the left mandible. A diffusion‐weighted image (DWI) and an apparent diffusion coefficient (ADC) map showed a heterogeneous hypointense mass in the left mandible. When a biopsy was performed under local anesthesia, the mass was diagnosed as an adenocarcinoma and found to be compatible with colon carcinoma metastasis to the mandible. There was no bone destruction or radiolucency of the left mandible on the panoramic radiograph. However, it was difficult to distinguish the mass lesion or abscess in the left mandible based on the CT image alone. Thus, since the patient had a medical history of malignancy with swelling and pain in the oral cavity, performing panoramic radiography not only with a CT image, but also with an MRI, including a DWI and an ADC map, was helpful in obtaining an accurate diagnosis. Shika Igaku (J Osaka Odontol Soc) 2019; Mar; 82(1):12‐18.
