Literature review of imaging, pathological diagnosis, and outcomes of metachronous lung and pancreatic metastasis of cecal cancer

Background: The common sites of colorectal cancer metastasis are the surrounding lymph nodes, liver, and lung, while ectopic metastases of the lung and pancreas are extremely rare. Here, we report a case of colorectal cancer with lung and pancreatic metastasis and analyze the histopathology, immunohistochemistry, and next-generation sequencing (NGS) to generate a differential diagnosis and treatment of metastatic colon cancer. Case presentation: A 78-year-old man was admitted because of a recently elevated carcinoembryonic antigen. This patient had undergone laparoscopic right hemicolectomy for cecal cancer IIA (T3N0M0) 5 years before admission and thoracoscopic left upper lung wedge resection for primary colon cancer lung metastasis 2 years before admission. Enhanced computed tomography revealed pancreatic metastasis. A laparoscopic distal pancreatectomy (combined with splenectomy) was performed. Postoperative pathology revealed colon cancer metastasis. We performed NGS on tumor samples at three loci and found colon cancer's most common oncogenic driver genes (KRAS, APC, and TP53). One month after surgery, the patient was given capecitabine for six cycles of chemotherapy. At present, no high adverse reactions have been reported. Discussion: For patients with pancreatic space-occupying, such as a previous history of colorectal cancer, and recent carcinoembryonic antigen elevation, we should highly suspect pancreatic metastatic colorectal cancer. Computed tomography and pathological histology have an excellent diagnostic value for pancreatic metastasis. NGS is an essential auxiliary for identifying metastatic tumors. Surgery combined with postoperative chemotherapy is an effective treatment.