Pancreatic cancer presenting as bowel obstruction and role of next generation sequencing: A case report

Introduction and importance: Pancreatic adenocarcinoma is one of the leading causes of death. Presentation with colonic metastases is far less frequently reported in the literature and may be misdiagnosed as colonic adenocarcinoma. We report the case of a female patient with metastatic pancreatic adenocarcinoma that presented with a sigmoid obstruction. Case presentation: A 66-year-old female presented with constipation and abdominal pain. She was found to have an obstructing sigmoid colon lesion, multiple metastatic lesions in the liver, and a pancreatic tail lesion. She underwent left hemicolectomy and ostomy placement. The gross pathology of the colon and needle biopsy of the liver was consistent of pancreatobiliary origin. Genomic screening performed, patient found to be KRAS G12R mutated. She was given one cycle of chemotherapy, thereafter was referred to hospice care. Clinical discussion: Primary metastatic pancreatic cancer is now the 2nd most diagnosed cancer in the United States after lung cancer. The prognosis for the malignancy is poor, patients are usually diagnosed late at the time that the tumor has metastasized to other organs. Colonic metastasis is a rarely seen and far less frequently reported in the literature. Next-generation-sequencing was performed at baseline to further characterize her tumor for any actionable mutations. Conclusion: Pancreatic adenocarcinoma is an aggressive malignancy with a poor prognosis. Next-generation-sequencing may offer targeted therapy if an actionable mutation is present such as our patient's, however due to late diagnosis, rapid clinical deterioration, and next-generation sequencing delay we were unable to alter the patient's outcome.