A Case of Solitary Metastatic Diaphragmatic Tumor from Resected Rectal Cancer

: A 54-year-old woman underwent high anterior resection with D3 lymphadenectomy for rectal cancer at another hospital. She was diagnosed with well-differentiated adenocarcinoma of rectal cancer, pT3, N1, H0, P0, M0, fStage III a. She did not receive adjuvant chemotherapy. Eighteen months after surgery, abdominal CT at our hospital showed a 19mm-sized mass in S7 of the liver. EOB-MRI also showed a mass in the same location. The mass was a ring contrast-enhanced lesion on dynamic phase, had a low signal pattern on liver cell phase, and had high signal pattern on diffusion-weighted imaging. As such, it was diagnosed as liver metastasis of rectal cancer, and surgery was performed. During surgery, the tumor was found to be located between the liver and diaphragm. Thus, we performed partial resection of the liver diaphragm. Histopathologically, the tumor was the same well-differentiated adenocarcinoma as the primary tumor. In addition, the tumor existed only in the diaphragm and was pumping out the liver. Therefore, we diagnosed the tumor as a diaphragm metastasis of rectal cancer. On literature review, only 8 reports of colorectal metastatic tumors involving the diaphragm were found.