Breast Adenocarcinoma and Cold Agglutinin Disease: A Paraneoplastic Syndrome.

Autoimmune hemolytic anemia is a disorder that is characterized by the destruction of red blood cells through an autoimmune process, such as temperature-dependent antibodies. The two predominant types, cold agglutinin and warm agglutinin disease, typically possess different underlying etiologies. Prompt recognition and workup of autoimmune hemolytic anemia should be prioritized to potentially uncover any underlying primary cause, such as malignancy. Here, we present the case of a 50-year-old female who presented with new-onset facial numbness and altered vision, in addition to fatigue and jaundice. Serum studies revealed evidence of severe hemolytic anemia, and subsequent imaging and biopsy confirmed the presence of metastatic breast adenocarcinoma. Breast adenocarcinoma is the most common cancer diagnosed in women in the United States, and it can be associated with paraneoplastic syndromes such as humoral hypercalcemia of malignancy. For breast cancer, autoimmune hemolytic anemia is a rare associated finding, especially as a presenting sign of malignancy. Therapy for her hemolysis and malignancy began promptly, which included starting anti-hormonal therapy for her malignancy and several courses of prednisone, which prompted moderate improvement. Plasmapheresis was initiated following a decline that showed short-term improvement to bridge to a more comprehensive cancer therapy that she ultimately was unable to tolerate. While autoimmune hemolytic anemia is rarely secondary to solid tumors, clinicians should maintain a high index of suspicion to uncover and treat serious illnesses.