Endobiliary metastasis of colorectal cancer: A rare presentation and diagnostic dilemma: A case report.

INTRODUCTION

Colorectal cancer is a common malignancy with liver metastases frequently encountered. However, endobiliary metastases are extremely rare and can pose significant diagnostic challenges as they can mimic primary biliary tumors.

PRESENTATION OF CASE: We report a 66-year-old female who underwent an extended right hemicolectomy for a well-differentiated adenocarcinoma of the transverse colon pT4aN1bM0. Two years after surgery, follow-up imaging revealed intrahepatic biliary dilation and subtle intraductal lesions, along with suspicious splenic nodules. Hepatic MRI confirmed the presence of endoluminal biliary nodules with upstream dilation. Percutaneous biopsy and immunohistochemical analysis showed tumor cells positive for CDX2 and negative for CD20, supported the diagnosis of intrabiliary colonic metastasis.

DISCUSSION: The clinical and radiological features of endobiliary metastasis can mimic those of primary biliary neoplasms, making accurate diagnosis challenging. While imaging modalities such as multiphasic CT and MRI are invaluable for lesion characterization, definitive diagnosis relies on tissue sampling and immunohistochemical profiling. Recognizing the possibility of endobiliary metastasis in patients with a history of colorectal cancer is crucial for appropriate management.

CONCLUSION

Increased awareness of endobiliary metastasis as a manifestation of colorectal cancer metastasis is essential for differentiating it from primary biliary tumors, optimizing therapeutic strategies, and ultimately improving patient outcomes.