Case 2 from the re-operation group. The patient operated on for left frontal oligo-astrocytoma developed right frontal EDH. Re-operation of EDH evacuation through craniotomy were performed, with further formation of contralateral EDH after the operation. A: Pre-op. MR of patient 2 (transverse, enhanced T1-weighted), showing tumor in the left frontal lobe, with heterogeneous T1-weighted signal and heterogeneous enhancement. The tumor was confirmed as oligo-astrocytoma by postoperative pathological examination. B: Intraoperative BUS identifying right frontal EDH. The patient was operated on through left frontal approach. C: CT scan 1 day after the right frontal epidural hematoma evacuation, identifying right parietal-occipital epidural hematoma.