Hematogone is a term applied to a subset of early B-lymphocytes, found in normal bone marrow, whose morphology greatly resembles that of leukemic lymphoblasts.
These cells are larger than the average mature lymphocyte, have scant cytoplasm, and a fine, soft chromatin texture; however, they are not quite as immature in appearance as a true leukemic lymphoblast. Hematogones are more common in younger children but can be found in bone marrow samples of patients at any age. They tend to be found in increased numbers within the bone marrows of patients recovering from bone marrow suppression. Common causes of increased concentrations of hematogones include: viral illness, chemotherapy recovery, and immune mediated cytopenias, such as idiopathic thrombocytpenic purpura (ITP). Hematogones are also common in patients with neuroblastoma.
With experience, knowledge of the patients underlying clinical condition, and the ability to review a patient's bone marrow, it is possible to distinguish hematogones from blasts. When necessary, a hematogone flow cytometry panel can be obtained to distinguish these benign cells from lymphoblasts.
Notice the size of these blast-like hematogones (see red arrows). They are larger than the few background lymphocytes present in these images. Notice the fine chromatin and scant cytoplasm. They are usually found mixed in with the full range of bone marrow cellular lineages, but can cluster with other lymphocytes within the spicules.