Cutaneous involvement by myeloid leukaemias: challenging cases with important implications

Myeloid leukaemias and precursors involving the skin are often challenging to diagnose with varied and overlapping clinical and histopathological features. Nonetheless, they are important for pathologists to recognize as they have significant implications for patient care. This article discusses cutaneous involvement by myelodysplastic syndrome (myelodysplasia cutis), acute myeloid leukaemia (myeloid sarcoma), and blastic plasmacytoid dendritic cell neoplasm. For each entity, the clinical and histopathological features are reviewed, along with key genetic features and a concise discussion of entities in the differential diagnosis. In addition, cutaneous involvement by chronic myelomonocytic leukaemia is briefly examined.