Intrinsic epidermoid cyst of the brainstem in children-review and case report.

PURPOSE: The study aimed to summarize all published cases of intrinsic brainstem epidermoid cysts in a timeline to highlight the specific characteristics and individualize the disease, in addition to discussing the best treatment used. METHODS: The scientific literature on pediatric cases of intrinsic epidermoid cysts of the brainstem was analyzed. We present the case of a 1.5-year-old male with incidental presentation, who was treated with gross total resection. We summarize all previously published cases to individualize the disease. RESULTS: We identified 21 patients, including 10 boys and 11 girls, with a mean age of 4.85 (1-15) years at the time of surgery. The most frequent symptoms were cranial nerve palsy (71.4%), pyramidal tract deficit (57.14%), and headache (52.38%). Among the affected cranial nerves, VII was the most frequently reported in 10 patients. CONCLUSION: Brainstem epidermoid cysts are extremely rare pathologies with relevant age involvement in young children. The treatment objective should be the maximum resection of the lesion through a careful approach and with the appropriate tools for the functional preservation of the patient.

Giant "heart appearance-like sign" on MRI in bilateral ponto-medullary junction infraction: case report.

BACKGROUND: Bilateral medial medullary infarction (MMI) is uncommon and bilateral medial pons infarction (MPI) is even rarer. "Heart appearance" on magnetic resonance imaging (MRI) is a characteristic presentation of bilateral medial medullary infarction (MMI). CASE PRESENTATION: We present 67-year-old Chinese diabetic and hypertensive female patient affected with "heart appearance-like" infarction in bilateral ponto-medullary junction on MRI. Abnormal signal was observed in the bilateral ponto-medullary junction on T1, T2, fluid-attenuated inversion recovery and apparent diffusion coefficient (ADC). The whole brain digital subtraction angiography (DSA) showed the basilar artery and vertebral artery remained intact. Therefore, we speculated that the bilateral ponto-medullary junction infarction might be caused by the deep perforating branch of the basilar artery. CONCLUSIONS: As far as we know, the "heart appearance-like" infraction in bilateral ponto-medullary junction was not reported. Our case also suggests that bilateral ischemic infraction involvement of the medulla and pon is possible even in the context of an intact basilar artery.

A rare case of a pediatric white epidermoid cyst.

White epidermoid cysts are a rare entity that present with atypical signal characteristics on MRI in comparison to typical epidermoid cysts. This can mislead a practitioner when trying to formulate a differential diagnosis based on imaging. We present the case of 15-year-old girl who presented with a pontine-medullar junction mass. This mass did not follow typical signal characteristics for known lesions. The mass was ultimately found to be an epidermoid cyst based on pathology findings. This lesion has rarely been reported in pediatric patients (J Pediatr Neurosci 9(1):52-54, 2014; Singap Med J 53(8):179-181, 2012). Here we present a rare case of an intracranial white epidermoid in a pediatric patient (Neurol India 62(5):577-579, 2014; Singap Med J 53(8):179-181, 2012; Am J Neuroradiol 19:1111-1112, 1998).

"The pen is mightier than the sword" - suicidal trans-orbital intracranial penetrating injury from a pencil.

A 40-year-old drug addict, who was being treated with methadone and occupational therapy, committed suicide by striking a wooden pencil into his right eye socket. While still conscious, he hit his head hard against a table, jamming the pencil even deeper into his head. The autopsy showed that the pencil missed the globe and lodged in the inner part of the right eye socket. It pierced the orbital part of the right ethmoid bone, the right ethmoid cells, and the right superior nasal concha, then passed through the body of the sphenoid bone and the clivus of the occipital bone before stopping in the brain tissue. The basilar artery was transected at the pontomedullary junction, where the tip of the pencil had lodged. Also, at the pontomedullary junction, an approximately 3 mm deep laceration of the brainstem was evident together with flecks of green paint. Histological examination revealed that laceration at the pontomedullary junction was even deeper than the macroscopic appearance had suggested, with several small lateral cracks, focal deep hemorrhage, and disruption of both gray and white matter of the brainstem. Fragments of cellulose originating from the wooden pencil could also be clearly distinguished. Toxicological analysis was performed using liquid chromatography with mass spectrometry, and it showed traces of methadone in the blood and humor vitreous samples. The cause of death was damage to the vital structures in the brainstem, resulting from a penetrating injury to the head by a pencil. Herein, we present a self-inflicted trans-orbital penetrating injury by a non-missile, low-velocity object - a pencil, with a rather unusual, immediately incapacitating outcome.

A posttraumatic pontomedullary rent with good outcome.

Posttraumatic pontomedullary rents have been described mainly as postmortem histopathological findings in patients who died immediately or within the first hours after trauma. To the best of our knowledge, no long-term survivors of this condition have been described, and those surviving initially were always severely impaired. We present the first patient with this condition and with corresponding lesions on imaging who survived longer than 3 months. Moreover, the patient regained almost complete independence 1 year after the trauma. We briefly discuss the proposed mechanisms of this injury. We conclude that this lesion, when incomplete, is not always lethal and can exceptionally have a good clinical outcome. Prevention of respiratory failure is of utmost importance in these patients.

Surgical Experience and Management of Intracranial Neurenteric Cysts: Single-Center Experience and Review of the Literature.

Introduction Neurenteric cysts (NECs) are rare, congenital lesions lined by endodermal cell-derived columnar or cuboidal epithelium. Based on previous studies, gross total removal of the capsule has been presumed to be the ideal surgical goal. Objective This series was undertaken to further understand the risk of recurrence based on the extent of capsule resection. Methods Records were retrospectively reviewed for all patients with radiographic or pathological evidence of intracranial NEC from 1996 to 2021. Results A total of eight patients were identified; four of eight (50%) presented with headache, and four had signs of one or more cranial nerve syndromes. One patient (13%) presented with third nerve palsy, one (13%) had sixth nerve palsy, and two (25%) with hemifacial spasm. One patient (13%) presented with signs of obstructive hydrocephalus. Magnetic resonance imaging demonstrated T2 hyper- or isointense lesions. Diffusion-weighted imaging was negative in all patients (100%) and T1 contrast-enhanced imaging demonstrated minimal rim enhancement in two patients (25%). In three of eight (38%), a gross total resection (GTR) was achieved, while in four (50%), a near-total resection, and in one (13%), a decompression was performed. Recurrences occurred in two (25%) patients, one with decompression and another with near-total resection, among these 1/2 required repeat surgery after a mean follow-up of 77 months. Conclusion In this series, none from GTR group demonstrated recurrence, while 40% of those receiving less than GTR recurred, underpinning the importance of maximally safe resection in these patients. Overall patients did well without major morbidity from surgery.

3-Dimensional Exoscope for Far Lateral Approach to Pontomedullary Cavernous Malformation.

Brainstem cavernous malformations account for 15%-18% of all central nervous system cavernomas and are histologically characterized by thin-walled, low-pressure capillaries, classically without intervening brain tissue.1,2 Cavernomas may be sporadic, typically characterized by a single lesion, or inherited. The inherited form is most often autosomal dominant with incomplete penetrance and variable expression. Multiple cavernomas are associated with the familial form; although this is not always the case, genetic workup should be pursued.3,4 Clinical presentation typically includes focal neurologic deficit related to hemorrhage location, seizures, and rarely obstructive hydrocephalus.1,2 Indications for surgical management include severe or progressive neurologic dysfunction, lesion size ≥2 cm, recurring hemorrhages, and/or significant mass effect.5 Microsurgical resection of a cavernoma is associated with an overall 28% complication rate and perioperative neurologic morbidity upwards of 45% according to some series. Long-term surgical outcomes at 12 months are more reassuring: 84% reported their condition to have improved or remained the same, and the long-term morbidity rate is 14%.1,6 The location of the lesion dictates the approaches available-cavernomas in the pons or medulla are commonly approached via a retrosigmoid or retrolabyrinthine approach, while more ventral pathologies in this region necessitate a far lateral approach.1,5,7,8 In Videos 1 and 2, we describe our experience with an exoscope-assisted far lateral approach to a pontomedullary cavernoma in a 10-year-old male presenting with numerous cavernomas and confirmed gene mutation. We demonstrate the exoscope's unparalleled visualization of the anterolateral brainstem, with nominal condylar drilling. The patient and his parents consented to the procedure and publication.

The Distance Between the Cranial Nerve IX-X Root Entry/Exit Zone and the Pontomedullary Sulcus: MR Imaging Study in Patients With Hemifacial Spasm.

Subject: To quantitatively describe the distance between the cranial nerve (CN) IX-X root entry/exit zone (REZ) and the pontomedullary sulcus in patients with hemifacial spasm (HFS). Methods: A total of 215 outpatients with HFS were recruited. Finally, 108 patients who yielded high-quality images were enrolled in the study. MRIs were reconstructed to measure the distance between the bilateral CN IX-X REZs and the corresponding pontomedullary sulcus. Results: Among the 108 patients, the ratio of males to females was 39/69, and the mean age was 57.9 ± 6.5 years. The ratio of left to right HFS involvement was 47/61. The average height was 1.62 ± 0.07 m, and the average body mass index (BMI) was 24.65 ± 2.97 kg/m2. The distance between the cephalic end of the CN IX-X REZ and the pontomedullary sulcus was 2.7 ± 0.9 mm. The distance between the caudal end of the CN IX-X REZ and the pontomedullary sulcus was 7.6 ± 1.1 mm. No monotonic relationship was found between distance and height or BMI in the scatter diagrams. Conclusions: The CN IX-X REZ is closely related to the pontomedullary sulcus in patients with HFS, and there is no difference between the left and right sides. The distances were not correlated with height or BMI in patients with HFS.

Outcome of Endoscope-Assisted Microvascular Decompression in Patients With Hemifacial Spasm Caused by Severe Indentation of the Brain Stem at the Pontomedullary Sulcus by the Posterior Inferior Cerebellar Artery.

BACKGROUND: Microvascular decompression (MVD) is the most effective treatment option for hemifacial spasm (HFS). However, deeply located forms of compression would require proper identification to allow for adequate decompression. OBJECTIVE: To describe the usefulness of endoscopic visualization in one of the most challenging compression patterns in HFS, where the posterior inferior cerebellar artery (PICA) loop is severely indenting the brain stem at the proximal root exit zone of facial nerve along the pontomedullary sulcus. METHODS: Radiological and operative data were checked for all patients in whom severe indentation of the brainstem by PICA at pontomedullary sulcus was recorded and endoscope-assisted MVD was performed. Clinical correlation and outcome were analyzed. RESULTS: A total of 58 patients with HFS were identified with radiological and surgical evidence proving brainstem indentation at the VII transitional zone. In 31 patients, PICA was the offending vessel to the facial nerve. In 3 patients, the PICA loop was mobilized under visualization of a 45° endoscope. A total of 31 patients had a mean follow-up duration of 52.1 mo. The mean duration between start of complaints and surgery was 7.2 yr. In the last follow-up, all patients had remarkable spasm improvement. A total of 5 patients had more than 90% disappearance of spasms and 26 patients experienced spasm-free outcome. CONCLUSION: Although severe indentation of brain stem implies morphological damage, outcome after MVD is excellent. A 45° endoscope is extremely helpful to identify compression down at the pontomedullary sulcus. Deeply located compression site can easily be missed with microscopic inspection alone.

Retrosigmoid Approach: A Simple and Safe Way to Resect Intrinsic Pontomedullary Lesions.

Objectives The main objective of this article is to describe a simple and safe protocol for the microsurgical management of ventrally located intrinsic pontomedullary lesions based on the retrosigmoid approach, cortectomy performed utilizing safe entry zones of the pons and medulla, and a delicate microsurgical resection. The intraoperative protocol includes redundant procedures that provide security in decision-making during surgery. Design A prospective series of 11 cases is presented. All patients were studied following the same clinical and imaging workup. A regular retrosigmoid craniotomy surgical approach was utilized. The peritrigeminal area in the pons and the olivary area in the medulla were considered as the safe entry zones. Neuronavigation of the white fiber tracts and electrophysiological monitoring were used as intraoperative aids to locate the lesions, the safe entry zones, and the placement of the cortectomy. Results Six lesions were pontine, two medullary, and the remaining six pontomedullary. Eight lesions were cavernomas, while the remaining three tumors. Overall, we obtained a postoperative functional improvement in the affected cranial nerves in 90.1% of the patients and a total or partial recovery of long ascending or descending pathway symptoms in 72.3% of the patients. All the patients were satisfied with the procedure and the results. Conclusions Radical resection of ventral intrinsic pontomedullary lesions displays a high degree of intraoperative reliability, and a good clinical result is possible using simple surgical procedures. The anatomical references are the first element in the decision-making process during surgery.

Microsurgical resection of an enlarging lateral pontomedullary cavernous malformation.

The extended retrosigmoid approach provides an excellent corridor to the lateral aspect of the pontomedullary junction (PMJ).1,2 This video demonstrates a microsurgical resection of a progressive enlarging cavernous malformation (CM) of the PMJ. The patient is a 33-year-old woman with progressive symptoms, including right facial droop, left hemianesthesia, diplopia, and nystagmus. The patient underwent a right extended retrosigmoid approach with intraoperative neuronavigation and neuromonitoring. Lower cranial nerve dissection allowed access to the lateral PMJ. A longitudinal corticotomy was performed above the glossopharyngeal. The CM was removed in a piecemeal fashion. Postoperative MRI confirmed gross-total resection and the patient remained neurologically stable. The video can be found here: https://youtu.be/K_TtiTo1RsQ.

Trans-labyrinthine Infra-trigeminal Approach for Recurrent Pontomedullary Cavernoma: A Step-wise Technical Note.

Recurrent brainstem cavernoma is a challenging lesion due to the neurological risks associated with different surgical approaches. In this technical report, we present a 35-year-old female with a history of multiple brain cavernomas. She underwent midline suboccipital craniotomy and trans-fourth ventricle approach for resection of the brain stem cavernoma following two major bleeding episodes, one year prior to the presentation. Following the trans-labyrinthine infra-trigeminal approach, the patient recovered well postoperatively with a baseline neuro exam and was discharged to acute rehab on postoperative day 5 (POD5). The translabyrinthine approach is a safe and effective corridor for pontine or pontomedullary lesions in carefully selected patients. Appropriate selection of surgical approach (based on location), meticulous surgical technique, and intraoperative neuromonitoring help in maximizing surgical resection while minimizing neurological deficits.

Progressive solitary sclerosis presented with diplopia: A case report.

OBJECTIVE: To report a patient presented with diplopia followed by progressive quadriparesis in the setting of a solitary pontomedullary lesion. CASE PRESENTATION: We report a 24-year-old woman presented with an attack of diplopia with full recovery, followed by progressive quadriparesis. The patient had a single pontomedullary lesion. Extensive diagnostic work up was negative. After follow up for 6 years, despite of clinical deterioration, the patient had the same pontomedullary lesion consistent with progressive solitary sclerosis. Corticosteroid pulse therapy and rituximab, didn't yield significant improvement, and the course was progressive, but after adding cyclophosphamide, partial improvement was seen. CONCLUSION: Progressive solitary sclerosis can cause progressive quadriparesis after an attack of diplopia without evidence of dissemination in time and space even after a prolonged period. This rare entity should be included in differential diagnosis of demyelinating lesions.

Resection of brainstem cavernous malformation via perifacial zone through retrosigmoid supracondylar approach.

Hemorrhagic brainstem cavernous malformations carry a high risk of progressive neurological deficits owing to recurrent hemorrhages and hence require complete surgical resection while minimizing damage to the dense concentration of nuclei and fibers inside the brainstem. To access lesions inside the lower pons, the senior author (H.B.) has preferred to approach the lesions via the "perifacial zone" through the pontomedullary sulcus from the inferior surface of the pontine bulge for more than 20 years.1,2 This video demonstrates a case of a cavernous malformation inside the lower pons, which was surgically treated via the pontomedullary junction through the retrosigmoid supracondylar approach in a half-sitting position. The lesion was completely removed in piecemeal fashion through a tiny incision on the sulcus, which did not cause any new neurological deficits. The modified Rankin Scale improved from 4 before the surgery to 1, and the patient had no recurrence during the 2 years of follow-up. The advantage of this access and the dissection techniques for this challenging lesion are introduced, based on our experience with more than 230 surgeries of brainstem cavernoma. The video can be found here: https://youtu.be/0H_XqkQgQ9I.

Extended Retrosigmoid Approach for the Resection of a Pontomedullary Junction Cavernous Malformation.

Objectives To describe an extended retrosigmoid approach for the resection of a cavernoma involving the ponto-medullary junction, with emphasis on the microsurgical anatomy and technique. Design A retrosigmoid craniotomy is performed in the lateral decubitus position and the sigmoid sinus exposed. After opening the dura, sutures are placed medial to the sinus to allow its gentle mobilization. Cerebrospinal fluid (CSF) is drained from the cisterna magna, and cerebellopontine cistern, and dynamic retraction is used over the cerebellum. Subarachnoid dissection of the cerebellopontine angle gives access to cranial nerves IX/X, VII/VIII, and VI. Inspection of the pontomedullary junction medial to the facial nerve reveals hemosiderin staining in that region. A small pial opening is made, exposing the hemorrhagic cavity. The cavernous malformation is then identified, dissected circumferentially, and resected. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The senior author performed the surgery. The video was edited by Drs. J.B. and V.N. Outcome Measures Outcome was assessed with extent of resection and postoperative neurological function. Results A gross total resection of the lesion was achieved. The patient did not develop any postoperative deficits. Conclusion Understanding the microsurgical anatomy of the cerebellopontine angle and meticulous microneurosurgical technique are necessary to achieve a complete resection of a brainstem cavernoma. The extended retrosigmoid approach provides an adequate corridor to the pontomedullary junction. The link to the video can be found at: https://youtu.be/FIKixWJT75w .

Functional consequences of ethidium bromide demyelination of the mouse ventral spinal cord.

Ethidium bromide (EB) has been extensively used in the rat as a model of spinal cord demyelination. However, this lesion has not been addressed in the adult mouse, a model with unlimited genetic potential. Here we characterize behavioral function, inflammation, myelin status and axonal viability following bilateral injection of 0.20 mg/mL ethidium bromide or saline into the ventral white matter (VWM) of female C57Bl/6 mice. EB-induced VWM demyelination significantly reduced spared VWM and Basso Mouse Scale (BMS) scores persisting out to 2 months. Chronic hindlimb dysfunction was accompanied by a persistent inflammatory response (demonstrated by CD45(+) immunofluorescence) and axonal loss (demonstrated by NF-M immunofluorescence and electron microscopy; EM). These cellular responses differ from the rat where inflammation resolves by 3-4 weeks and axon loss is minimal following EB demyelination. As these data suggest that EB-injection in the mouse spinal cord is a non-remyelinating lesion, we sought to ask whether wheel running could promote recovery by enhancing plasticity of local lumbar circuitry independent of remyelination. This did not occur as BMS and Treadscan assessment revealed no significant effect of wheel running on recovery. However, this study defines the importance of descending ventral motor pathways to locomotor function in the mouse as VWM loss results in a chronic hindlimb deficit.