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Intracranial dermoid cysts are rare congenital lesions that result from abnormal sequestration of ectodermal cells during neural tube formation. These tumors are especially rare in lateral areas such as in the temporal lobe. In this study, we report a case of dermoid cyst located in the right temporal lobe. A 50-year-old man was referred for further treatment of a tumor. CT revealed a low-density mass lesion in the right temporal lobe, with calcification. MRI showed the lesion with high signal intensity on diffusion-weighted imaging, high-low mixed signal intensity on T1-weighted imaging, and iso-high signal mixed intensity on T2-weighted imaging; the capsule was enhanced with gadolinium. Differential diagnosis included dermoid cyst, epidermoid cyst, teratoma, and neurenteric cyst. We decided to perform surgery for the improvement of his symptom, histopathological diagnosis, and radical cure. A right temporal craniotomy was performed, and the tumor was found adherent to the surrounding brain tissue. The tumor was completely removed under subpial dissection. Hair was confirmed in the tumor content. On histopathology, the cyst wall was lined with stratified squamous epithelium, sebaceous glands, small vessel aggregates, and inflammatory infiltrate. Keratinized material and hair were found in the lumen. The patient was discharged 7 days after surgery with no new neurologic deficits. This case was unusual in terms of the effect of gadolinium enhancement on MRI, and the presence of adipose tissue and calcification were useful for diagnosis. It is vital to consider prevention of chemical meningitis due to intrathecal dissemination of the tumor content intraoperatively.

Objective: This study aimed to determine whether the apparent diffusion coefficients (ADCs) determined by diffusion-weighted imaging (DWI) of magnetic resonance imaging (MRI) could facilitate the malignancy grading of various gliomas. Methods: Sixty patients with a primary cerebral glioma underwent diffusion-weighted and gadolinium-enhanced (Gd) T1-weighted MRI using a 1.5-T MRI scanner. Scoring was performed based on signal intensities on DWI and Gd images. The mean and minimum ADC values were calculated, and Ki-67 staining was performed for each histological sample to evaluate their tumor proliferative potential. Then, the DWI, Gd, and combined scores were analyzed and compared with the Ki-67 staining index and malignant grade. The relationships among the mean and minimum ADC values, Ki-67 staining index, and malignant grade were also evaluated. Results: The minimum ADC was inversely correlated with the Ki-67 staining index, with a low minimum ADC suggestive of tumor malignancy. The qualitative evaluation of the D score of water molecule diffusion on DWI accurately reflected the pathological grades of gliomas, with an effectiveness that was at least as good as the quantitative analysis using the minimum ADC. The diagnostic value of Gd images in determining glioma malignancy grades was inferior to that of DWI. Conclusion: Both DWI and gadolinium-enhanced images of MRI should be considered essential for the diagnosis of tumor malignancy.

In chronic subdural hematoma (CSDH) patients, motor functions usually recover quickly after burr-hole surgery; however, in a rare case, the hemiparesis showed poor improvement after surgery. In that case, investigation of cerebral infarctions is important. Among the 284 CSDH patients with motor weakness, magnetic resonance image (MRI) and MR angiography (MRA) were acquired in 82 patients before surgery when the hemiparesis progressed rapidly. Small lacunar infarction was identified on the hematoma side in five cases; all were older than 80 years with hypertension, and diabetes mellitus had been diagnosed in two. In all the five patients (100%), MRA demonstrated a downward or upward shift of the M1 portion of the middle cerebral artery on the hematoma side, where the perforating arteries originate. Conversely, only 4 CSDH patients (5.2%) without lacunar infarction demonstrated M1 downward shift. The risk factors of lacunar infarction were high in the five detected cases; however, distortion, twisting, or elongation of the lenticulostriate arteries might be a cause of the lacunar infarctions, rather than the formation of lipohyalinosis or microatheroma in the arteries. Therefore, anti-platelet treatment might not be necessary for CSDH-inducing lacunar infarction. The lacunar infarctions caused by CSDH were small, the patients' hemiparesis was mild, a prognosis of all the patients was good, and they recovered well from the motor weakness after physical rehabilitation. MR examinations before surgery are recommended for CSDH patients especially when a patient complains of sudden onset or rapid deterioration of motor weakness.

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