case_images: PMC9345088_01
case_images: MR images obtained before surgery. (a and b): Gd-enhanced T1-weighted axial images. (c): Gd-enhanced T1-weighted sagittal images. The size of the tumor is 19 x 13 x 13 mm3, and it is present in the tectum (white arrow, b, c ). The aqueduct can be seen on the ventral side of the tumor (black arrow, b,c). Both inferior horns of the lateral ventricle are enlarged. (d):FLAIR sagittal images. A FLAIR high-signal area is observed in the entire midbrain surrounding the Gd-enhanced lesion.
case_images: SNI-13-319-g001.jpg
case_images: PMC9345088_01_SNI-13-319-g001.jpg
case_images: F1
case_images: Contrast-enhanced magnetic resonance imaging (MRI) showed a markedly contrast-enhanced mass in the dorsal midbrain and obstructive hydrocephalus [Figure 1].
case_images: Intraoperative findings. (a) Swollen tectal plate (black arrow) with aqueductal stenosis (arrowhead). (b and c) Partial removal of the abnormal lesion using a flexible endoscope and biopsy forceps. (d) After the biopsy of the lesion is completed, a third ventriculostomy is performed. In this picture, the floor of the third ventricle is expanded with a balloon.
case_images: SNI-13-319-g002.jpg
case_images: PMC9345088_01_SNI-13-319-g002.jpg
case_images: F2
case_images: A Neuroport mini (Hakko Co., Nagano, Japan) was inserted into the anterior horn, and observation using a flexible endoscope (VEF-V, Olympus, Tokyo, Japan) showed that the aqueduct was stenotic due to the tumor, and the posterior part of the aqueduct was swollen [Figure 2a-c]. After thorough intraventricular lavage to prevent dissemination, a third ventriculostomy was performed using an expanding balloon catheter (Expander Balloon Catheter SI Fuji Systems, Tokyo, Japan) [Figure 2d].
case_images: Histopathological findings of the tumor. (a) Hematoxylin and eosin staining (x40) shows dense proliferation of bare nucleated cells with enlarged nuclei and increased chromatin density. (b-d) The tumor cells are CD3 negative (b), CD20 positive (c), and CD79a positive (d) on immunohistochemistry.
case_images: SNI-13-319-g003.jpg
case_images: PMC9345088_01_SNI-13-319-g003.jpg
case_images: F3
case_images: The final histopathological diagnosis of the tumor was diffuse large B-cell lymphoma [Figure 3].