Granulocytic sarcoma of the brain in a patient with acute myeloid leukemia.

Granulocytic sarcoma is extramedullary tumor composed of immature leukemic cells most frequently located in close proximity to bone, but it also can be found in the skin, breast, gastrointestinal tract, ovaries and brain. Granulocytic sarcoma may arise during the course of leukemia or precede its development in the bone marrow. The majority of reported cases of granulocytic sarcomas in acute myleoid leukemia have chromosome translocation t(8;21). We report a 46-year-old man with acute myeloid leukemia, type M2 involving the marrow and peripheral blood and chromosome t(8;21) who developed granulocytic sarcoma in the brain, as a first manifestation of relapse 6 months after complete remission was achieved. During a neurosurgical operation a cortically located tumour (3.5 x 5 cm) in the brain was partially removed. Histology showed tumor consisted of homogenous infiltrate of blasts, admixted with more mature haematopoietic cells. The blasts have large round to oval nuclei, delicate chromatin, one or more small well-defined nucleoli and scant basophilic cytoplasm. Immunohistochemistry showed that blast cells were myeloperoxidase positive, confirming the diagnosis of myeloblastic sarcoma in the brain. The patient died two days after surgery.