Colloid adenocarcinoma of the pancreas diagnosed after pancreaticoduodenectomy: a case report

Abstract

Abstract Introduction Colloid adenocarcinoma of the pancreas is a rare malignant epithelial tumor representing 1%–3% of pancreatic cancers. It is histologically characterized by abundant extracellular mucin containing sparse neoplastic cells. Case description A 68-year-old male presented with jaundice, pruritus, and weight loss. Laboratory results revealed cholestasis and elevated CA 19-9 (310 U/ml). Contrast-enhanced CT demonstrated a 3.5 cm hypodense lesion in the pancreatic head with biliary and pancreatic duct dilatation, without vascular invasion or metastasis. Pancreaticoduodenectomy was performed. Histopathology revealed mucin pools with cribriform and tubular clusters of atypical epithelial cells consistent with colloid adenocarcinoma. Immunohistochemistry was positive for CK7 and MUC2, focally CDX2, and negative for MUC1. Resection margins and all 17 lymph nodes were free of tumor. The postoperative course was uneventful, and the patient remained disease-free at 12 months. Discussion Colloid adenocarcinoma is a rare pancreatic tumor with distinctive histological and immunohistochemical features, often associated with intraductal papillary mucinous neoplasm. Recognition of this entity is essential due to its relatively favorable prognosis compared with ductal adenocarcinoma. Learning points Colloid adenocarcinoma of the pancreas is a rare malignant epithelial tumour representing about 1–3% of pancreatic ­cancers, characterised by abundant extracellular mucin with sparse neoplastic cell clusters. Its immunohistochemical profile MUC2 and CDX2 positivity with MUC1 negativity supports intestinal differentiation and helps distinguish it from conventional ductal adenocarcinoma. It frequently arises from intestinal-type intraductal papillary mucinous neoplasms (IPMNs), which represent its main ­precursor lesions. Compared with ductal adenocarcinoma, colloid carcinoma demonstrates less aggressive behaviour and better ­postoperative survival outcomes, with reported 5 year survival rates around 40-55% after complete resection. Accurate recognition through imaging, pathology, and immunoprofiling is essential to optimise management and avoid misclassification.