A morphometric study of the nuclear and cytoplasmic shape of a blastic population in a case of HM-A.L.L. was performed by comparing the two differently shaped populations with and without HM configuration. The results obtained using analytical size-independent parameters created by the S.A.M. work-station enable us to characterize the shape of both blastic cell populations quantitatively, and strongly suggest the existence of shape modulation from one cellular type toward the other. Thus a possible sequence from blastic cells (having regular, rather round nuclei) to HM cells (characterized by high distortion of both nucleus and cytoplasm) was proposed.