Malignant cutaneous lesions.

An 81-year-old woman presented with fatigue, loss of appetite and painless skin lesions, which had developed suddenly. Other than type 2 diabetes, her history was unremarkable; she did not use any medication. On physical examination, several erythematous purple-reddish papules and plaques were observed on her leg (figure 1A) and trunk (figure 1B). Blood count showed anaemia (7.1 mmol/L), thrombocytopenia (36×109/L) and leucocytosis (17.2×109/L) with 5.2×109/L blast cells in the peripheral blood smear (figure 1C). Biopsy of a skin lesion revealed a dense dermal infiltration by medium-sized monomorphic cells with blast-like appearance (figure 1D). Through additional immunohistochemistry, the diagnosis of a blastic plasmacytoid dendritic cell neoplasm (BPDCN) was made. Figure 1 (A and B) Macroscopic appearance of the cutaneous lesions on the patient's left leg and on the right side of the trunk, respectively. (C) Peripheral blood smear showing blast cells. (D) …