We present 2 cases of hepatocyte nuclear factor 1α (HNF1α)-mutated adenomatosis, discovered for reasons unrelated to this disease, and identified using immunohistochemical methods. These new tools may further our understanding of the link between adenomas/adenomatosis subtypes and their complications, and their association with other abnormalities. We present 2 cases of hepatocyte nuclear factor 1α (HNF1α) -mutated adenomatosis, discovered for causes unrelated to this disease, and identified using immunohistochemical methods. These new tools may further our understanding of the link between adenomas / adenomatosis subtypes and their complications, and their association with other abnormalities.