The presence of pain usually rules out malignancy. the leukemia may recurs as a lymphnode swelling and not as a pain.as the leukemia is a disease of blood cells, it usually recurs as a presence of blasts(abnormal cells) in peripheral blood smear or bone marrow
. if your peripheral smear and bone marrow are in remission, it has nothing to do with recurrence of leukemia. But the pain may be due to the thrombosis
of the deep veins of leg, which should be diagnosed with doppler examination of lower limbs. planning transplant means you may be having unfavourable cytogenetics. if you dont have a perfect match for transplant, you can ask for MUD(matched unrelated donor) transplant or umbilical cord stem cell
transplant. you need to discuss with your hematologist
for these options.