MRI Findings of Central Nervous System Granulocytic Sarcoma (Chloroma)

ABSTRACT

PURPOSE: To characterize MRI findings of central nervous system(CNS) granulocytic sarcoma (chloroma) and to analyse the points which differentiate it from other CNS tumors. MATERIALS AND METHODS: We evaluated MRI in six patients with CNS granulocytic sarcoma proven by surgery or bone marrow biopsy (intracranical, one case and spine five cases). A 0.5T superconductive MR machine was used for diagnosis and, axial, coronal and sagittal T1- and T2-weighted spin echo images and Gd-DTPA enhanced T1-weighted images were obtained. We retrospectively analized the location, signal intensity, margin, contrast enhancement and homogeneity, and bony change around the tumor. RESULTS: MRI findings of CNS granulocytic sarcomas were as follows one tumor was seen to be an extra-axial mass in the posterior fossa of the brain, four were epidural, and one was an epidural and presacral masses in the spine ; tumor magins were lobulated and three were smooth. On T1-weighted images, all tumors were of isoignal intensity; on T2-weighted images, four were of isosignal intersity and two were of high signal intensity. Contrast enhancement was inhomogeneous in five of six cases. Bony change around the tumor was seen in two cases. CONCLUSION: On T1-weighted images, CNS granulocytic sarcomas (chloromas) were of isosignal intensity, relative to brain parenchyma or spinal cord ; on T2-weighted images, they were of iso or high signal intensity, with relative contrast enhancement. These points could be useful in differentiating them from other CNS tumors.