Name:
Right occipital transtentorial approach for a pineal malignant germ cell tumor
Description:
Right occipital transtentorial approach for a pineal malignant germ cell tumor
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/192f2f61-2a06-4ac8-9082-f4fac6f79368/videoscrubberimages/Scrubber_292.jpg
Duration:
T00H06M22S
Embed URL:
https://stream.cadmore.media/player/192f2f61-2a06-4ac8-9082-f4fac6f79368
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/192f2f61-2a06-4ac8-9082-f4fac6f79368/21-51.mp4?sv=2019-02-02&sr=c&sig=RDu0Ph9eWhSemhNcFQg2YBaLBKr35EuDQ6bi3RkxwEw%3D&st=2024-05-02T11%3A53%3A26Z&se=2024-05-02T13%3A58%3A26Z&sp=r
Upload Date:
2021-10-27T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
SPEAKER: This video demonstrates the surgical resection of a malignant germ cell tumor of the pineal region via an occipital transtentorial approach. The patient was a 15-year-old male with no significant past medical history who initially presented with headaches and occular findings consistent with a Parinaud’s syndrome. An MRI performed at that time showcased a large pineal region tumor. His serum AFP levels were elevated; however, his serum beta-HCG levels were within normal limits.
SPEAKER: He underwent an endoscopic biopsy and then discovered third ventriculostomy at an outside institution. The pathology results were consistent with the diagnosis of yolk sac tumor with enteric differentiation. After placement of an Ommaya reservoir, he was started on an intrathecal chemotherapy regimen, which included carboplatin, etoposide, and ifosfamide.
SPEAKER: After two rounds of induction chemotherapy, his clinical symptoms had improved. A repeat MRI scan demonstrated that his tumor had decreased in size. And his AFP levels dropped markedly, but were still above the normal range. However, following his sixth round of chemotherapy, he started to develop worsening headaches and a recurrence of his Parinaud’s.
SPEAKER: Repeat imaging demonstrated a significant increase in the size of the tumor, and his germ cell markers were notable for an interval increase in his serum AFP level. Platinum-based chemotherapy is the initial treatment of choice for nongerminomatous germ cell tumors, such as yoke sac tumors. In comparison to germinomas, nongerminomatous germ cell tumors have a higher relapse risk and a worse prognosis.
SPEAKER: As a result, multimodality therapy is often required. Candidates for delayed resection or second look surgery include patients who fail to respond to chemotherapy, the presence of residual tumor with negative serum or CSF markers after chemotherapy and/or radiation, or suspected growing teratoma syndrome. The latter diagnosis refers to the clinical situation in which the patient has normal or decline in germ cell markers, but a solitary enlarging tumor following induction chemotherapy.
SPEAKER: This occurs in 10% of nongerminomatous germ cell tumors. Surgical corridors which permit access to the pineal region include the posterior hemispheric transcultural approach, the occipital transtentorial approach, the midline supracerebellar infratentorial approach, and the paramedian or lateral supracerebellar infratentorial approach. For this case, we selected the occipital transtentorial approach.
SPEAKER: This corridor permits a wider exposure of the midline and expanded working angles, in addition to facilitating greater access to the inferior aspect of the lesion, which extended into the cerebellum mesocephalic tissue. The patient was placed in 3- point head fixation, using the Mayfield skull clamp, and positioned in the right lateral decubitus position to exploit gravity retraction on the ipsilateral occipital lobe.
SPEAKER: A lumbar drain may be placed prior to starting the procedure, in order to facilitate dissection of the interhemispheric fissure. However, this was not required in this case, as we were able to remove CSF from his Ommaya reservoir during the procedure. The head was turned inferiorly, the vertex was elevated, and the neck was flexed in order to make the falx as perpendicular to the floor as possible.
SPEAKER: The patient was then registered to the neuronavigation software, using the preoperative MRI. A midline sagittal incision was made over the parietal region, and a generous right parietal craniotomy was fashioned, extending across the midline to the contralateral side. The dura was opened in a U-shaped fashion and elevated towards the sagittal sinus. Following removal of CSF from the Ommaya reservoir, the interhemispheric fissure was carefully dissected.
SPEAKER: Every attempt was made to preserve bruising veins, but one can be removed for safety, if necessary. The operating microscope was brought in at this time. A small incision is made in the tentorium lateral to the straight sinus. The edges of the tentorium are then sectioned and carefully coagulated. A cottonoid is used to protect the underlying cerebellum, and a monopolar cautery is then used to advance the tentorial opening through to the incisura.
SPEAKER: The arachnoid overlying the quadrigeminal cistern was then widely opened, affording us an excellent view of the dorsal surface of the tumor. Blunt dissection of the tumor capsule is then performed, in order to define tissue planes around the lesion. The tumor is then debulked and removed in a piecemeal fashion from the quadrigeminal plate down to the fourth ventricle.
SPEAKER: The final portion of the tumor was firmly attached along the velum interpositum. Bridging vessels in this region were cauterized and divided, and the adherent tumor was then removed. Cotton balls are used to verify the extent of tumor resection. In this manner, a radical subtotal resection was accomplished with the removal of all visible tumor and an excellent view into the third ventricle at the end of the resection.
SPEAKER: The patient did well neurologically. His postoperative MRI was consistent with a radical subtotal resection. A small amount of residual remained where the tumor was densely adherent to the deep venous system. The final tumor pathology was consistent with yolk sac tumor, with concomitant regional malignant somatic transformation to an enteric mucinous adenocarcinoma.
SPEAKER: In conclusion, second-look surgery is a good alternative for patients with malignant germ cell tumors which don't respond to initial neoadjuvant treatment. The occipital transtentorial approach provides excellent exposure for pineal region tumors, particularly multicompartment lesions, as illustrated in this case. Microsurgical techniques and internal debulking while paying attention to preserving the tumor-brain interface permits aggressive resection of these lesions.
SPEAKER: