Thrombotic microangiopathy manifesting as thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in the cancer patient.

The complication of thrombotic thrombocytopenic purpura or hemolytic uremic syndrome (TTP/HUS) can occur in cancer patients. It is characterized by a microangiopathic hemolytic anemia, severe thrombocytopenia, and renal failure. Pulmonary manifestations, especially pulmonary edema, are a common observation. Neurologic changes are also frequently seen. The etiology is unknown at this time. It has been observed in many different types of cancer and is most commonly seen in gastric adenocarcinoma followed by carcinoma of the breast, colon, and small cell lung carcinoma. The hemolysis can be massive and is due to red cell fragmentation, as schistocytes are present in all the cases. Though immune complexes are present in the plasma, the antiglobulin (Coomb's) test is negative. Chemotherapeutic agents, especially mitomycin C, have been implicated as causative factors. There is a correlation of this complication with the cumulative dose. However, chemotherapy cannot account for all the cases as the syndrome can occur in untreated patients. It can be differentiated from disseminated intravascular coagulation by the absence of a coagulopathy. Management should consist of plasma exchange, use of a Staphylococcus aureus column (Prosorba), and control of hypertension. Because of the susceptibility to pulmonary edema, blood volume overloading should be avoided.