Haematodermic neoplasm is a recently recognized condition, characterized by tumour cells expressing CD4, CD56 and CD123. This phenotype is strongly suggestive of a plasmacytoid dendritic cell origin. This haematopoietic malignancy is a distinct clinicopathological condition with frequent skin involvement, an evolution toward leukaemia and a rapidly aggressive course. We report the case of a 64-year-old woman who presented with a haematodermic CD4+CD56+CD123+ neoplasm affecting the left cheek; the initial staging was otherwise negative. Despite this early stage of the disease, aggressive treatment including methotrexate-asparaginase and local radiotherapy was proposed as first-line therapy. Complete clinical remission was rapidly reached and the patient was still alive after > 30 months of follow-up. To date there is no consensus on the first-line treatment for such patients but intensive treatment is probably needed immediately even in cases of localized disease. The response obtained with CHOP (cyclophosphamide, doxyrubicin, vincristine, prednisone) or CHOP-like chemotherapy regimens is disappointing. Other regimens, such as those used in acute leukaemia, may improve the outcome of these patients.