KAPOSIS-SARCOMA IN AN HIV-NEGATIVE CLL PATIENT AS THE CAUSE OF THROMBOCYTOPENIA

A patient is described with a rapidly progressive Kaposi's sarcoma fol lowing immunosuppressive therapy with fludarabine monophosphate (FAMP) for chronic lymphocytic leukemia. The development of this tumor was a ccompanied by progressive thrombocytopenia, due to trapping of the pla telets in the Kaposi sarcoma, without signs of consumptive coagulopath y or microangiopathic hemolytic anemia. This sequestration process mig ht be caused by the abnormal structure of the tumoral vessels, leading to exposure of subendothelial structures like collagen, von Willebran d's factor, and tenascin to the vessel lumen. A severe immunosuppressi on due to the lymphocytotoxic effect of FAMP on several T-cell subpopu lations was seen. This case confirms the importance of immunosuppressi on as a cofactor in the development of Kaposi's sarcoma also in HIV-ne gative patients, and adds Kaposi's sarcoma to the differential diagnos is of thrombocytopenia in immunosuppressed patients.