A marker chromosome in post-transplant bone marrow

Detection of small supernumerary marker chromosomes in karyotype analysis represents a diagnostic challenge. While such markers are usually detected during cytogenetic studies of constitutional chromosome abnormalities, they have also been found in specimens submitted from patients with acquired malignancies. We report here the detection of a marker chromosome in a bone marrow specimen from a patient who received a bone marrow transplantation. We discuss the importance of proper characterization and interpretation of marker chromosomes in clinical practice.