Granulocytic sarcoma/chloroma

Granulocytic sarcoma (chloroma) describes extramedullary collections of leukemia cells. These collections can occur, albeit rarely, as the sole evidence of leukemia. In a review of three AML studies conducted by the former Children's Cancer Group, fewer than 1% of patients had isolated granulocytic sarcoma, and 11% had granulocytic sarcoma along with marrow disease at the time of diagnosis.[4] This incidence was also seen in the NOPHO-AML 2004 (NCT00476541) trial.[5]

Patients with isolated granulocytic sarcoma have a good prognosis if treated with current AML therapy.[4]

In a study of 1,459 children with newly diagnosed AML, patients with orbital granulocytic sarcoma and central nervous system (CNS) granulocytic sarcoma had better survival than patients with marrow disease and granulocytic sarcoma at other sites and AML patients without any extramedullary disease.[5,6] Most patients with orbital granulocytic sarcoma have a t(8;21) abnormality, which has been associated with a favorable prognosis. The use of radiation therapy does not improve survival in patients with granulocytic sarcoma who have a complete response to chemotherapy. However, radiation therapy may be necessary if the site(s) of granulocytic sarcoma do not show complete response to chemotherapy or for disease that recurs locally.[4]

CNS involvement is often described as extramedullary disease and included in overall summaries of extramedullary disease. However, it has a distinct prognostic impact and requires therapeutic alterations. It is therefore discussed in detail in sections for both prognosis and treatment.