FDG-PET/CT とMRI が診断の一助となった腎細胞癌骨梁間型骨転移の1例

Abstract

We report a case of renal cell carcinoma with intertrabecular vertebral metastases detected by F-18 fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) and magnetic resonance imaging (MRI). The patient was a 40-year-old female, referred to our hospital for fever of ＞ 38°C, and loss of body weight. Examination showed anemia and elevated C-reactive protein (CRP). Abdominal enchanced CT showed a mass 3 cm in diameter, located on left kidney. She was diagnosed with left renal cell carcinoma (cT1aN0M0). Laparoscopic radical nephrectomy with a transabdominal approach was performed. Histological findings showed clear cell renal cell carcinoma G2＞G3. Although after operation, she presented with fever of ＞38°C, anemia, and elevated CRP and alkaline phosphatase. Systemic bone scan could not detect any bone metastases, but FDG-PET/CT and lumber MRI revealed cancer invasion to the bone of the whole body. Histological findings at bone biopsy showed clear cell carcinoma infiltrating the marrow space. We diagnosed the case as bone metastases of intertrabecular vertebral type. She was treated with temsirolimus, but died about five months after her first visit. Intertrabecular vertebral metastases that infiltrate the marrow space without trabecular bone alteration are not visible on radiographs or bone scans. FDG-PET/CT and MRI are more useful for diagnosis of intertrabecular vertebral metastases such as in this case.