Donath-landsteiner hemolytic anemia with erythrophagocytosis and platelet phagocytosis in peripheral smear: Rare findings

The Donath-Landsteiner (DL) hemolytic anemia or paroxysmal cold hemoglobinuria (PCH) is a rare subtype of autoimmune hemolytic anemia (AIHA). We report here a case of a 22-year-old young female who presented with acute onset shortness of breath. Routine hematological investigation revealed erythrophagocytosis and platelet phagocytosis by monocytes in peripheral blood smear, which are rarely reported in AIHA, especially the DL. The unusual blood smear findings directed the pathologists to initiate workup for hemolytic anemia that yielded positive results in direct Coombs test C3d (Complement) and direct DL test. The findings confirmed the case as DL hemolytic anemia. To the best of our knowledge, this is the first report of both erythrophagocytosis and platelet phagocytosis in peripheral blood smear in PCH.