[Intraparenchymal granulocytic sarcoma in acute monocytic leukemia; case report]

Granulocytic sarcoma of the parenchyma of the brain present in a patient with acute monocytic leukemia, and its unusual course during treatment, is described. Four years after diagnosis of acute monocytic leukemia, a 24-year-old man developed severe headache during its remission period. The CT scan showed large intraparencymal mass in the right frontal lobe, which was partially removed and diagnosed as granulocytic sarcoma. Following the operation, radiation in total dose of 35.5 Gy was given to the whole brain, and there was also left intraventricular administration of methotrexate (MTX) and cytosine arabinoside (ara-C). The treatment resulted in the complete disappearance of the intraparenchymal mass apart from small calcifications. Five months later, the patient redeveloped severe headache with consciousness disturbance. CT scan revealed marked swelling in the left cerebral hemisphere with irregular contrast-enhanced areas. The patient died of brain herniation in spite of conservative therapy. Photomicroscopic findings of the left cerebral hemisphere proved the presence of "disseminated leukoencephalopathy" and the absence of tumor cells. On the other hand, the right frontal lesion consisted of no tumor cells but scar tissues. This unusual feature of the CT scan in the terminal stage might be caused by combination with the effect of highly concentrated MTX in the left cerebral hemisphere because of the increased permeability of the ependym and the relatively high radiosensitivity in the non-affected left cerebral hemisphere.