A case of microglioma of the brain in a 48-year-old man, diagnosed by the histopathological examination of the tumor mass removed by surgical operation was presented. The tumor with somewhat ill defined outlines was located at the left frontal inferior portion of the right cerebellum. Microscopically, there was diffuse infiltration of the brain with tumor cells forming collars around the blood vessels. Various tumor cell elements are mostly mixed with lymphocytes. Gomori's silver stain reveal an increased perivascular reticulin fibers and splitting of the reticulin fibers by the tumor cells.