Abstract
A 43 year old woman presented with acute myeloid leukaemia, marked finger and toe clubbing, and a hilar mass. Biopsy of the hilar mass was not technically possible, but it almost certainly represented a granulocytic sarcoma since chemotherapy induced rapid resolution of the mass along with reversal of the clubbing and remission of the leukaemia. Relapse of the leukaemia 21 months later was associated with return of the clubbing. It is hypothesized that an abnormal circulation within the granulocytic sarcoma may have accounted for the development of clubbing.