Abstract
BACKGROUND: Metastasis of pancreatic cancer to the colon is rare and the features need to be further elucidated. Herein, we report a rare case of pancreatic cancer with simultaneous liver and colon metastases. CASE SUMMARY: A 48-year-old man with intrahepatic space-occupying lesions based on a computed tomography scan was admitted to our hospital for further treatment. Abdominal magnetic resonance imaging revealed a 6.4 cm × 4.2 cm mass in the tail of the pancreas and multiple low-density masses in the liver parenchyma. In addition, a mass of 2.2 cm × 1.6 cm with surface congestive erosions in the sigmoid colon was detected by colonoscopy. Histopathological examination of biopsies from both the liver and colon lesions revealed a moderately to poorly differentiated adenocarcinoma. Immunohistochemical staining of the colon tumor was positive for cytokeratin (CK) 7 and CK, but negative for colorectal adenocarcinoma-related markers CK 20, CDX2, and SATB2, thus indicating that the metastasis originated from the pancreas. Next-generation sequencing for genomic profiling of the liver and colon metastases both found mutations in KRAS (p.G12D) and TP53 (c.376-1delG), with microsatellite stable and low tumor mutational burden without actionable or cancer-predisposing gene mutations detected. The patient was subsequently treated with 12 cycles of FOLFIRINOX which led to a sustainable response, followed by ongoing maintenance treatment with irinotecan plus fluorouracil. CONCLUSION: For this rare case, careful evaluation of histopathological and immunohistochemical staining results are required. The genomic profiling of colon lesions was revealed for the first time, and FOLFIRINOX showed good treatment efficacy in this patient.