Abstract In this video, we demonstrate epidermoid tumor microsurgical resection of the cerebellopontine angle (CPA) performed by the senior author (K.I.A.). Epidermoid tumors arise from ectoderm trapped within/displaced into the central nervous system. They show predilection for CPA Angle (up to 40%), 4th ventricle, suprasellar region, and spinal cord.1 They are the 3rd most common CPA tumor, comprising approximately 7% of CPA pathology. CPA lesions can produce 5th and 7–12th cranial nerve neuropathies.2 3 4 Recurrent episodes of aseptic meningitis caused by cyst content rupture may occur. Symptoms include fever, meningeal irritation, and hydrocephalus. A 26-year-old female presented with headaches. Head magnetic resonance imaging (MRI) revealed right CPA tumor with brain stem compression (Fig. 1, A–C). There was evidence of restricted diffusion in diffusion-weighted imaging, typical of epidermoid tumor. Surgery was performed in prone position with head turned 25 degrees to the ipsilateral side using retrosigmoid craniotomy.5 Tumor was ventral to the 7th and 8th cranial nerve complexes, between the 5th nerve as well as toward the brainstem. The surgical plan was gross total resection with tumor capsule resection to prevent recurrence.6 (Small residuals can be left behind when capsule is adherent to critical structures.) Tumor was adherent to brain stem perforators which were preserved using meticulous dissection. Cranial nerves and vascular structures were also left intact. We irrigated with antibiotic saline and used perioperative treatment to prevent aseptic meningitis. The pathohistological diagnosis revealed epidermoid tumor cyst. Postoperative MRI revealed complete resection (Fig. 1, D–F). The patient recovered fully and was neurologically intact. The link to the video can be found at: https://youtu.be/LyWl-KZUSGY.

Abstract This video demonstrates microsurgical resection of low-grade (Grade I) thoracic spinal cord astrocytoma. Astrocytomas are the most common pediatric intramedullary tumors and occur secondary to ependymomas in adults.1,2 The treatment goal should be radical gross total resection while preserving neurological function with intraoperative neuromonitoring.2-4 To our knowledge, this is the first video report on microsurgical resection of low-grade spinal cord astrocytoma.  A 58-yr-old female presented with gait disturbances has been featured in this video. A spinal MRI revealed T1/T2 hyperintense intramedullary tumor at T4, suggesting spinal cord astrocytoma versus ependymoma. Dura was opened in the midline and tacked to the surrounding muscle tissue with tacking sutures. The arachnoid was opened separately with microscissors, keeping it intact for closure at the end of surgery. Liga clips were applied to hold the arachnoid to the dura. Myelotomy was done in the midline,5 opening the posterior median sulcus over the length of the tumor and extending proximally and distally a few millimeters beyond the tumor.3,5 The tumor reduction was achieved by coagulation or debulking. Once sufficient debulking was achieved, dissection of the tumor margins toward surrounding cord was performed. Preoperative recording of motor-evoked potentials (MEPs) compared with continuous intraoperative MEPs were essential for preserving the neurological function and quality of life. The intraoperative finding of a clear tumor plane of resection carries positive prognostic significance and reduces the risk of complications.2,3,6  A pathohistological diagnosis showed a low-grade (Grade I) spinal cord astrocytoma (pilocytic). Follow-up MRI showed no sign of tumor or recurrence. The patient recovered fully and was neurologically intact. Written consent was obtained directly from the patient.

SUMMARY – Spinal dumbbell tumors are defined by a narrowing at the point where they penetrate the intervertebral foramina or dura mater, assuming an hourglass or dumbbell shape. Dumbbell-shaped spinal hemangiomas are extremely rare. We describe a dumbbell spinal tumor (epidural cavernous hemangioma) resected by a 2-stage single-sitting combined approach. We also conduct a substantial literature review of the subject. We present a case of a 78-year-old male who was found to have a homogeneously enhancing, dumbbell-shaped, intraspinal, extradural tumor mass extending into the left chest cavity. The tumor was resected with a single-sitting 2-stage posterior technique: a microsurgical approach, followed by endoscopic resection via a thoracoscopic approach. There are several reports in the literature on the combined approach for dumbbell tumors of the spinal cord. Our case is the first to describe 2-stage combined surgery in 1 sitting for dumbbell hemangioma with the patient in the lateral decubitus position for the thoracoscopic part of the surgery; and the use of a fat pad, which was applied in the neuroforamen via the posterior route, as a marker for resection during the transthoracic procedure.

Abstract Trigeminal neuralgia is a chronic pain disorder affecting the face. In approximately 80% of cases, it is most commonly caused, when the root entry zone (REZ) of the trigeminal nerve is compressed by the superior cerebellar artery (SCA). The etiology of the remaining 20% of cases is distributed among venous, arteriovenous malformations, posterior fossa tumors, multiple sclerosis plaque compressions, and other pathologies. Combinations of those compressive factors are very rare.1 2 3 4 Herein, we present a video clip of microvascular decompression (MVD) in a 73-year-old female, who has failed conservative treatment with 6 medications over 10 years. She was affected by a unique triple compression of the right REZ by the SCA, anterior inferior cerebellar artery (AICA), and petrosal vein complex (Fig. 1A). Right-sided microsurgical decompression of the REZ of the trigeminal nerve through standard retrosigmoid craniotomy was performed by the senior author (K.I.A.). The SCA and AICA were separated from the nerve using Teflon pledgets. The petrosal vein complex was coagulated and divided, freeing up the right trigeminal nerve (Fig. 1B). The patient was discharged home on the third postoperative day with complete resolution of trigeminal neuralgia. The link to the Video can be found at: https://youtu.be/PYVvImGW0yE.

SUMMARY – Epithelioid hemangioendothelioma is a rare vascular brain tumor. It develops from endothelial cells, usually in the liver, lung, bone and soft tissue. Primary localization of this tumor in the intracranial space is very uncommon; only 47 cases have been described in the literature. This tumor was initially classified as grade I (benign) in the World Health Organization (WHO) 2007 classification. In 2016, this tumor was re-classified as grade III (malignant). Herein, the first case report of epithelioid hemangioendothelioma in the cerebellum of a male patient is presented. Complete surgical excision was done. No adjuvant therapy was administered. Magnetic resonance imaging performed 2 years after the surgery continued to show no recurrence of the tumor. To our knowledge, this is the first report of cerebellar location of this rare tumor. In addition, the authors report drastic re-classification of the epithelioid hemangioendothelioma from the benign tumor (WHO 2007) to a malignant one (2016), which significantly changes postoperative management and follow up of this brain neoplasm.