Warm Autoimmune Hemolytic Anemia Associated with Pancreatic Adenocarcinoma Showing Ectopic Expression of Band 3 Protein: A Case Report.

Autoimmune hemolytic anemia (AIHA) is rare in solid tumors and may represent a paraneoplastic phenomenon. We describe the case of a 73-year-old woman with unresectable pancreatic adenocarcinoma who developed steroid-refractory warm AIHA. Prednisolone partially improved her anemia but not her hemolysis. Chemotherapy with modified FOLFIRINOX followed by gemcitabine plus nab-paclitaxel improved both the tumor and anemia, enabling steroid tapering. Conversion surgery revealed the ectopic expression of band 3 in tumor cells. This case suggests that anti-band 3 antibodies may mediate paraneoplastic AIHA and emphasizes the importance of tumor control in steroid-refractory cases.