Myelodysplastic syndrome (MDS), acute myeloid leukaemia (AML) and chronic myeloproliferative disorder (CMPD) in cats

Histological, enzyme histochemical and ultrastructural findings in three ca ses of feline bone marrow neoplasia are described. The following changes we re observed: in myelodysplastic syndrome (MDS), a low medullary blast count , strongly atypical (micromegakaryocytic) proliferative megakaryocytopoiesi s, hypoplastic erythrocytopoiesis with impairment of differentiation, multi focal extravasation and lymphoid aggregates; in acute myeloid leukaemia (AM L), medullary proliferation of undifferentiated cell types; in chronic myel oproliferative disorder (CMPD), trilinear medullary proliferation with comp lete cellular maturation, osteomyelosclerosis and extramedullary haemopoies is. In two cases (MDS, AML), ultrastructural demonstration of C-type virus particles (feline leukaemia virus) suggested a viral aetiology. (C) 1999 Ha rcourt Publishers Ltd.