Aleukaemic leukaemia cutis as an initial manifestation of myeloid/NK cell precursor acute leukaemia

Aleukaemic leukaemia cutis is a rare condition characterized by infiltration of leukaemic cells into the skin before they appear in the peripheral blood. We report a case of an aleukaemic leukaemia cutis, which had a history of exposure to atomic bomb radiation. A 57-year-old Japanese woman initially presented with a 20-week history of multiple red papules and plaques mainly over the trunk. Histological examination revealed the infiltration of atypical monocytic cells in the dermis, but no leukaemic cells were detected in the peripheral blood. Twenty-three weeks after the appearance of the eruption, leukaemic cells were detected in the peripheral blood for the first time. The results of immunohistochemistry of the skin biopsy specimen and flow cytometry of the peripheral blood indicated the rare phenotype of myeloid/NK cell precursor acute leukaemia. This is the first case report of myeloid/NK cell precursor acute leukaemia presenting as aleukaemic leukaemia cutis in the English literature, and awareness of this clinical presentation may be important to reach the correct diagnosis.