Bone marrow pathology after bone marrow transplantation

Trephine biopsy evaluation in patients who have undergone high dose chemotherapy with stem cell infusion performed by an experienced pathologist is important in evaluation of hematopoietical restitution, evaluation of complications such as graft rejection, infections, relapse or secondary neoplasms. In the first week after high dose chemotherapy or radiotherapy bone marrow aplasia is evident. In the case of accompanying myelofibrosis, fragmentation of reticular and collagen fibers is noticeable only following stem cell transplantation. The first precursors, which appear after the second or third week after transplantation are erythroid precursors found in small groups. Promyelocytes and myelocytes are observed between the second and fourth week, the ration off erythroid to myeloid populations at that time is 1:1. Megakaryocytes ate the last precursors to appear. Trephine biopsy evaluation is useful in diagnosis of graft rejection, especially in case of a discrepancy between the blood morphology examination and bone marrow cellularity. Granuloma formation is an unspecific finding, which requires diagnosis of infections. Residual disease can be recognized in histopathologic examination, or sooner, with immunophenotyping, cytogenetic examination using FISH or PCR. Secondary neoplasms to high dose radiotherapy or chemotherapy are usually lymphoproliferative processes connected with latent EBV infections, myelodysplastic syndromes and acute myeloblastic leukaemia.