Isolated testicular and bone relapse in children with acute myeloblastic leukemia and chronic graft versus host disease after allogeneic BMT.

Isolated extramedullary relapse after allogeneic bone marrow transplantation (BMT) for acute myeloblastic leukemia (AML) is very unusual, particularly in patients with graft versus host disease (GVHD) known to be associated with decreased incidence of leukemic relapses. However, these rare occasions have been suggested to result from the escape of leukemic cells at the immune-privileged sites. Here we report two unusual post-transplant cases with AML: the first developed testicular relapse during the treatment of chronic GVHD (cGVHD) and bronchiolitis obliterans and the second relapsed as granulocytic sarcoma in the proximal tibia two years after BMT.