A Howell–Jolly body is a cytopathological finding of basophilic nuclear remnants (clusters of DNA) in circulating erythrocytes.
During maturation in the bone marrow, late erythroblasts normally expel their nuclei; but, in some cases, a small portion of DNA remains.
[2][3] This DNA appears as a basophilic (purple) spot on the otherwise eosinophilic (pink) erythrocyte on a standard H&E stained blood smear.
These inclusions are normally removed by the spleen during erythrocyte circulation, but will persist in individuals with functional hyposplenia or asplenia.
Common causes include asplenia (post-splenectomy) or congenital absence of spleen (right atrial appendage isomerism).