Introduction:
Myeloid sarcoma (MS) is a rare extramedullary tumour which may precede or occur concomitantly with bone marrow involvement in acute myeloid leukemia, myelodysplastic syndrome, or blast crisis in chronic myeloproliferative disorder. Myeloid sarcoma is most commonly found in lymph nodes, skin, subcutaneous tissue and gums, while it is less common in bones, the retroperitoneal space and eye socket.

Case Report:
The case is reported of a 65-year-old woman with chronic myelogenous leukemia treated for about 20 years with hydroxyurea, 6-mercaptopurine and tyrosine-kinase inhibitors. During the treatment, the general condition of the patient progressively deteriorated, lymphadenopathy and splenomegaly worsened, and blast crisis was diagnosed. After the first cycle of induction chemotherapy, the patient’s lymph nodes were swollen and painful. One of the lymph nodes was subjected to histopathology, on the basis of which a diagnosis of MS was made. As the patient showed no response to the treatment, palliative care was initiated. Three months after the diagnosis of MS, the disease progressed. The patient died of infectious complications

Conclusions:
A diagnosis of MS, which is considered an adverse prognostic factor, significantly reduces the chances of remission and overall survival in patients with acute myelogenous leukemia or blast crisis inchronic myeloproliferative disorders. It seems that early confirmation of the diagnosis and initiation of the treatment adjusted to the patient’s clinical condition may improve the prognosis and increase the response rates.