ISOLATED EXTRAMEDULLARY RELAPSE IN KNEE-JOINT AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION FOR PH ALL

We report a patient who relapsed in a patella and knee joint after all ogeneic bone marrow transplantation (BMT) for Ph chromosome-positive a cute lymphoblastic leukemia. The patient complained of pain and swelli ng of knee joint 14 months post-BMT. Fluid from the knee joint include d leukemic cells consistent with the immunophenotype of blasts prior t o BMT and also revealed the bcr/abl transcript by reverse-transcriptas e polymerase chain reaction. Magnetic resonance imaging demonstrated a n abnormal signal in the patella, Radiotherapy to the localized extram edullary lesion was successful and no bone marrow relapse has been det ected cytologically and cytogenetically to date. This case suggests th at the physician should be aware of unusual relapse sites of leukemia post-BMT.