case_images: PMC11799722_01
case_images: Contrast-enhanced brain magnetic resonance imaging preoperative. (a) Contrast-enhanced T1 image in the axial section that shows a mass in the right frontal horn (arrow), which seems to obstruct the ipsilateral foramen of Monro. (b) Contrast-enhanced T1 image in axial view, 5 mm above image a, which shows the same tumor (thin arrow); furthermore, it shows ventricular dilation (empty arrow) with transependymal edema (thick arrow). (c) Contrast-enhanced T1 image in sagittal view shows the tumor in the right foramen of Monro (arrow). (d) Contrast-enhanced T1 image in coronal view, which evidences the tumor in the lower edge of the right frontal horn (arrow) close to the ipsilateral foramen of Monro. (e) T2 image shows a tumor in the right frontal horn, isointense (arrow thin), associated with ventricular dilation (empty arrow) and transependymal edema (thick arrow). (f) Diffusion-weighted image shows no restriction of the tumor of the right frontal horn (arrow).
case_images: SNI-16-5-g001.jpg
case_images: PMC11799722_01_SNI-16-5-g001.jpg
case_images: F1
case_images: The contrast-enhanced brain magnetic resonance imaging (MRI) showed a mass at the right frontal horn of the lateral ventricle adjacent to the foramen of Monro that generates a dilation of that horn; it is isointense on T1, contrast-enhancing, with irregular but defined borders, isointense on T2, which does not restrict diffusion [Figure 1].
case_images: (a) Intraoperative image, showing a brownish gray tumor (thin arrow), hypervascularized (thick arrow), by endoscopic view using a handmade endoport (empty arrow). (b) Intraoperative endoscopic image with a handmade endoport (empty arrow), where the same tumor is shown (thick arrow) with defined borders (thin arrow) that allow distinguishing the tumor from the medial wall of the right frontal horn of the lateral ventricle. (c) Intraoperative image with partial resection tumor with moderate bleeding (thin arrow), where the resection continued with aspiration (thick arrow). (d) Nonenhanced brain computed tomography (CT) on the 1st postoperative day, absence of tumor, with little bleeding in the surgical field is shown (thin arrow), also the distal end of the external ventricular catheter is seen (empty arrow). (e) Enhanced brain CT on the 5th postoperative day, without external ventricular shunt, where there is no evidence of contrast-enhancing lesions, with little bleeding in the surgical field (arrow).
case_images: SNI-16-5-g002.jpg
case_images: PMC11799722_01_SNI-16-5-g002.jpg
case_images: F2
case_images: It was decided to operate endoscopically, with the use of a handmade endoport, where we saw a gray-brownish, hypervascularized tumor adjacent to the foramen of Monro, with defined borders at the anterior and medial plane, with insertion in the lateral and posterior region, as well as in the floor of the ventricle [Figure 2]. The postoperative contrast-enhanced brain CT appears to be a total resection of the tumor, without hydrocephalus, with little bleeding in the surgical field, and without abnormal contrast enhancement [Figure 2].
case_images: Microscopic description: (a) Proliferation of malignant glandular formations (green arrow) immersed in a mucinous matrix. Note the presence of choroid plexuses with benign characteristics (red arrows). Hematoxylin and eosin (HE) x4. (b) Malignant glandular epithelium, with mucinous cytoplasm. HE x10. (c) Malignant cells were positive for CK20. HE x4. (d) They were also positive for beta catenin. HE x10.
case_images: SNI-16-5-g003.jpg
case_images: PMC11799722_01_SNI-16-5-g003.jpg
case_images: F3
case_images: The result of the pathological anatomy showed that it was a metastatic mucosecretory type adenocarcinoma, cytokeratin 20 (CK20) positive, B catenin positive, cytokeratin 7 (CK7) negative, thyroid transcription factor - 1 (TTF1) negative, glial fibrillary acidic protein (GFAP) negative, neuron-specific enolase (NSE) negative, Ki67 90-95%, suggestive of the colon as a possible primary [Figure 3].
case_images: Contrast-enhanced brain magnetic resonance imaging in the 4th postoperative month. (a) Contrast-enhanced T1 image in axial view shows a new metastasis, nodular, contrast-enhancing in the inferior border of the IV ventricle (arrow). (b) Contrast-enhanced T1 image in sagittal view shows the metastasis in the IV ventricle (arrow); in addition, the lesion recurrence in the right front horn is seen (empty arrow). (c) Contrast-enhanced T1 image in axial view shows the recurrence of the contrast-enhancing right frontal horn tumor (arrow), without associated ventricular dilation. (d) T2 image shows a recurrence of the right frontal horn tumor, isointense (thin arrow), that seems to invade the cavum vergae (empty arrow) and not the former surgical field. (e) Diffusion-weighted image shows no signal restriction (arrow).
case_images: SNI-16-5-g004.jpg
case_images: PMC11799722_01_SNI-16-5-g004.jpg
case_images: F4
case_images: In addition, a contrast-enhanced brain MRI was performed during the hospitalization, which showed a recurrence/residual tumor in the right frontal horn of the lateral ventricle, as well as another metastasis in the IV ventricle, without hydrocephalus [Figure 4].