A 43-year-old woman with a temporal mass.

A 43-year-old woman with a past medical history of breast cancer and an acute myeloid leukemia (AML) presented with headache over a 3-week period. The clinical examination was completely unremarkable. CT and MRI scans showed a contrast enhancing lesion in the left temporal lobe. Histopathologic examination revealed a malignant, hematopoietic tumor with high mitotic activity, areas of necrosis and diffuse infiltration of the brain parenchyma. Positive staining for Chloroacetateesterase and lysozyme of tumor cells identified its myeloid lineage. The diagnosis was granulocytic sarcoma (GS)/chloroma, a metastatic manifestation of AML. Granulocytic sarcoma (GS) most often occurs in patients with AML, myelodysplastic syndromes and myeloproliferative disorders, and can involve any organ. However intracerebral manifestation of GS is a rare event. In this case histopathological features and differential diagnoses of intracerebral GS are discussed.