Granulocytic sarcoma preceding AML M0 and the diagnostic value of CD34

Granulocytic sarcoma with no demonstrable abnormalities in the peripheral b lood or bone marrow is a rare but recognised initial manifestation of acute myeloid leukaemia and has led to diagnostic difficulties in some cases. A lymph node excisional biopsy from a patient presenting with cervical lympha denopathy, a mediastinal mass, and a normal peripheral blood picture was re ported to have features suggesting a T cell non-Hodgkin lymphoma, for which she was subsequently treated. However, 10 months later the patient develop ed acute myeloid leukaemia, FAB classification M0. The initial lymph node b iopsy was reviewed and further immunohistochemical studies using antibodies against CD34 led to a revised diagnosis of primary granulocytic sarcoma.