BackgroundThe incidence of acute epidural hematoma not accompanied by fracture is low, and it mostly occurs right below the impact point in children. Acute epidural hematoma on the contralateral side of the impact point without fracture is very rare.Case presentationCase 1: a 52-year-old Japanese woman fell and was bruised in the left occipital region, and acute epidural hematoma developed in the right frontal region. No fracture line was observed in the right frontal region on head computed tomography or during surgery, and the source of bleeding was the middle meningeal artery. Case 2: a 56-year-old Japanese man fell down the stairs and was bruised in the right occipital region, and acute epidural hematoma developed in the right occipital supra- and infratentorial regions and left frontal region. Separation of the lambdoid suture was noted in the right occipital region, but no fracture line was present in the left frontal region on either head computed tomography or during surgery, and the source of bleeding was the middle meningeal artery.ConclusionsTwo rare cases of frontal contrecoup acute epidural hematoma without facture near the hematoma were reported. It is possible that the dura mater detaches from the inner surface of the skull due to cavitation theory-related negative pressure and blood vessels in the dura mater are damaged, causing contrecoup acute epidural hematoma even though no fracture occurs, for which careful course observation is necessary.

INTRODUCTION The frequency of intraorbital tumors is small as 0.9% of all brain tumors, but its pathological type is diverse. Among them, the diagnosis of whether particularly malignant tumor scan clinically, is extremely important. Nuclear medical testing is essential for non-invasive differential diagnosis in brain tumors. SPECT, good malignancy differentiation, evaluation of malignancy, usefulness such as differentiation of non-tumorous lesions have been reported many. However, there are few reports that SPECT was useful in preoperative differential diagnosis of orbital tumors. Since 123IMP-SPECT was useful in preoperative differential diagnosis of intraorbital tumors, we report some literature considerations. METHOD Among the 27 cases of intraorbital tumors that were operated on in our clinic between August 2005 and August 2016, 14 cases of SPECT prior to surgery were examined for the usefulness of preoperative differential diagnosis. Breakdown of cases, as the malignant tumor, two cases of malignant lymphoma, MALT lymphoma 2 cases, adenoid cystic carcinoma 1 case, in one case plasma cytoma, as a benign tumor, false tumors 4 cases, three hemangioma cases, neurocytoma 1 case it was. RESULTS In IMP early image, accumulation of clear IMP was observed in all six cases of malignant tumors. In benign tumors, there is no accumulation in hemangioma and neurosheath, there is a strong accumulation in one of the four cases in false tumors, it was observed mild accumulation in the remaining two cases. Tumor to normal ratio of IMP early image was an average of 2.39 in six malignant tumors and 1.52 in 8 benign tumors. CONCLUSION This time, we examined the usefulness of 123IMP-SPECT in preoperative differential diagnosis of intraorbital tumors. The T/N ratio of intraorbital malignant tumors is higher than benign tumors, and it was thought to help to evaluate preoperative malignancy of intraorbital tumors.