Metastasis of rectal adenocarcinoma to the pancreas. Two case reports and a review of the literature

Context: The vast majority of pancreatic tumors are of pancreatic origin. Nonetheless, a variety of extrapancreatic tumors can involve the pancreas and may manifest with different clinicopathological characteristics. Case report: We report on two patients with a history of rectal cancer who were referred to our department with a pancreatic mass: one patient 2 years after a low anterior resection (TNM stage: pT3 pN0 pM0), the other patient 2.5 years after an abdominoperineal resection (TNM stage: pT3 pN1 pM0). In the first case, computed tomography showed a cystic mass in the pancreas but fine-needle biopsy followed by cytopathological analysis revealed only necrotic tissue. In the other patient, magnetic resonance tomography showed a hypodense structure in the pancreatic body/ tail. Suspecting pancreatic tumors, distal pancreatectomies were carried out. Subsequent histological examination revealed metastases of rectal cancer in both cases. Conclusion: In patients with a history of a malignant tumor, a newly diagnosed mass in the pancreas - although rare - should raise the suspicion of metastatic disease. Surgical resection may be an option for a curative approach which can be offered to otherwise healthy patients if there is no evidence of other metastases.