Incontinentia pigmenti (IP) is a rare X-linked genodermatosis in which skin changes are combined with anomalies of other tissues, mainly of ectodermal origin. Mutations of the IKBKG gene are responsible for IP. Haematological disorders among IP patients are rare. Four female patients from a single family, with typical clinical characteristics of IP, are reported. In addition, all affected family members show a distinct haematological phenotype: hypogranular granulocytes, leucocytes with pseudoplatelets, and different anomalies of nuclei. Pseudoplatelets are a typical finding in patients with leukaemia. As there is dysfunction of the IKBKG gene in leukaemia, it is hypothesised that mis-regulation of the NEMO pathway may cause the appearance of pseudoplatelets in acute leukaemias as well as in IP. These observations suggest that IP may not be only linked to skin and organs of the ectodermal origin.