Pancreatic Metastasis from Rectal Cancer that was Diagnosed by Endoscopic Ultrasonography-guided Fine Needle Aspiration (EUS-FNA)

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

Background

Pancreatic metastasis from colorectal cancer is 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

AC1

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. At that time, the patient was thought to have pancreatic metastasis from colon cancer. He underwent laparoscopic distal pancreatectomy (combined with splenectomy). 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. NGS is an essential auxiliary for identifying metastatic tumors. Surgery combined with postoperative chemotherapy is an effective treatment.

Metachronous Pancreatic Metastasis from Rectal Cancer that Masqueraded as a Primary Pancreatic Cancer: A Rare and Difficult-to-Diagnose Metastatic Tumor in the Pancreas

BACKGROUND Pancreatic metastasis from colorectal cancer is rare and can masquerade as primary pancreatic cancer. CASE REPORT A 70-year-old male was diagnosed with advanced rectal cancer with multiple liver metastases. After neoadjuvant chemotherapy, he underwent radical surgery for the primary tumor and hepatectomy for multiple liver metastases. Adjuvant chemotherapies and additional surgeries were subsequently required for recurrences in the liver, lung, and lymph nodes. A diffuse hypovascular nodule in the pancreatic head and a solitary liver metastasis were detected 2.5 years after the initial surgery and he accordingly underwent further chemotherapy. However, the pancreatic tumor progressed, invading the pancreatic duct and biliary tract. Obstructive jaundice finally prompted discontinuation of chemotherapy and he underwent biliary drainage. His diffuse and hypovascular tumor was clinically and radiographically diagnosed as a primary pancreatic cancer. Pancreatic resection for the pancreatic tumor and hepatectomy for the liver metastasis were performed 4.2 years after the initial surgery, achieving radiographic and surgical curative resection. Pathological examination of the surgical specimen resulted in a definitive diagnosis of metachronous pancreatic metastasis from his primary rectal cancer. Despite further chemotherapy, his general condition worsened; however, he remains alive 5.4 years after the initial surgery, with best supportive care. CONCLUSIONS Pancreatic metastasis originating from rectal cancer can masquerade as primary pancreatic cancer clinically and radiologically. Multimodality treatment is mandatory for metastatic colorectal cancer. Aggressive surgeries for pancreatic metastasis should be considered if curative resection appears possible radiographically and/or intraoperatively.