Characterized by the sudden development of multiple seborrheic keratoses, associated with an underlying malignancy. Inherited loss of RBC anchor proteins leading to complement-mediated intravascular hemolysis. Often triggered by infection, acidosis, or other physiologic stress. Patients are at risk for pancytopenia, aplastic anemia, and Budd-Chiari syndrome.

Patient 1:

Young man who developed iron-deficiency anemia and pancytopenia who presented with jaundice and dark tea-colored urine, ultimately diagnosed with paroxysmal nocturnal hemoglobinuria.