Septostomy and Monroplasty in Isolated Lateral Ventricle After Removal of a Third Ventricle Colloid Cyst: 2-Dimensional Operative Video.

Isolated unilateral hydrocephalus (IUH) is a condition caused by unilateral obstruction of the foramen of Monro.1 Etiopathogenic causes include tumors, congenital lesions, infective ventriculitis, intraventricular haemorrhage, and iatrogenic causes such as the presence of contralateral shunts.2,3 Neuroendoscopic management is considered the "gold-standard" treatment in IUH.4 Even if endoscopic septostomy and foraminoplasty in IUH are well-known procedures,5,6 IUH after an interhemispheric transcallosal transchoroidal approach for removal of a III ventricle colloid cyst is a complication barely described in literature. Video 1 describes this rare complication and the neuroendoscopic treatment adopted, including the operative room setup, patient's positioning, instrumentation needed, and a series of intraoperative tips for the performance of septostomy and Monroplasty via a single, precoronal burr hole. The scalp entry point and endoscope trajectory, homolateral to the dilated ventricle, were planned on the neuronavigation system. The avascular septal zone away from the septal veins and body of the fornix was reached, and the ostomy was performed. At the end of the procedure, Monroplasty was performed, too. The procedure was effective in solving the hydrocephalus and patient's clinical picture. No surgical complications occurred. Imaging demonstrated an evident and progressive reduction of enlarged lateral ventricle. In authors' opinion, the single burr-hole approach, ipsilateral to the enlarged ventricle, provides an optimal identification the intraventricular anatomy and allows Monroplasty to be performed, if deemed feasible during surgery. The patient consented to the procedure. The participants and any identifiable individuals consented to publication of their images.

Gamma Knife Radiosurgery for Third Ventricular Colloid Cysts: A Retrospective Study.

INTRODUCTION: Colloid cysts often occur in the third ventricle, and they are considered benign, slowly growing lesions. They commonly present with symptoms of intracranial hypertension and rarely sudden death due to acute hydrocephalus. The management options include cerebrospinal fluid diversion procedure by shunt, endoscopic or transcranial surgical excision, and stereotactic aspiration. Complications associated with excisional procedures make them undesirable to some patients. Stereotactic radiosurgery has emerged as a noninvasive less risky treatment option. To date, there is no clinical series in the literature reporting on this treatment modality. The aim of the study was to determine the efficacy and safety of gamma knife (GK) radiosurgery in the treatment of third ventricular colloid cysts. METHODS: This is a retrospective study involving 13 patients with third ventricular colloid cysts who underwent GK radiosurgery. GK radiosurgery was used as a primary treatment in all the patients. The median prescription dose was 12 Gy (11-12 Gy). The cyst volumes ranged from 0.2 to 10 cc (median 1.6 cc). RESULTS: The median follow-up was 50 months (18-108 months). Cyst control was achieved in 100% of the patients. Complete or partial response was observed in 12 patients (92%). Eight patients (62%) had hydrocephalus on imaging at the initial diagnosis. Seven of these patients had VP shunt insertion before GK. One patient required shunt insertion after GK. CONCLUSION: GK for third ventricular colloid cysts is a promising treatment, regarding its efficacy and safety, to be added to other treatment options. A longer follow-up is required to confirm long-term control.

Interhemispheric Transcallosal Resection of Large Colloid Cyst Through Nondilated Foramen with Use of Microblade Retractor: 2-Dimensional Operative Video.

Patients who present with a large colloid cyst (CC) and nondilated ventricles represent a therapeutic challenge.1-3 Although transcallosal approaches provide reliable access to the lateral ventricle and foramen of Monro, direct visualization of the vascular attachment of the CC to the roof of the third ventricle is not always possible. This can be especially true with CCs located more posteriorly and superiorly.4 Opening of the choroidal fissure can improve access and visualization to the posterior third ventricle; however, this maneuver is associated with some element of risk.5 There is a paucity of operative video in the literature illustrating the technique of gentle, microblade elevation of the fornix to improve visualization into the third ventricle and, on occasion, avoid the need to open the choroidal fissure.6 We report the case of a 28-year-old woman who presented with headaches and progressive short-term memory dysfunction (Video 1). Magnetic resonance imaging demonstrated a 17-mm CC associated with distortion and thinning of the bilateral fornices without hydrocephalus. The patient was offered interhemispheric, transcallosal resection. Intraoperatively, gentle elevation of the fornix with a microblade retractor facilitated access to the vascular attachment of the colloid cyst-obviating the need to open the choroidal fissure. The index operative video discusses the technical nuances associated with trans-callosal resection of CC with use of the microblade retractor. Special emphasis is placed on the intricate relationship of neighboring anatomic structures. The patient consented to the procedure and the publication of her image.

Colloid Cyst: Revision of Third Ventricular Zones for Risk Stratification of Hydrocephalus.

OBJECTIVE: We sought to reclassify the "anatomic risk zones of colloid cysts" as proposed by Beaumont et al, by proposing newer landmarks, and to assess predictive value for the risk of occurrence of hydrocephalus with the new classification compared with the old. METHODS: A retrospective cohort of 122 cases of colloid cyst of third ventricle were categorized into zones 1, 2, or 3 based on Beaumont's classification (old zone) and our classification (new zone) based on radiologic images. We attempted to recategorize these zones by assigning new anatomic landmarks. The difference in zonal distribution of colloid cyst and association with hydrocephalus was studied using the 2 methods of zonal classification. RESULTS: Per the old zone classification, 3/122 patients were in zone 2, whereas 21/122 were in zone 2 per the new zone classification. The new zone method had a higher specificity (36.21% vs. 5.263 %) and positive predictive value (63.37% vs. 54.23%) for occurrence of hydrocephalus in patients with colloid cyst. The Spearman correlation showed better correlation with the new method for occurrence of hydrocephalus (rho = 0.4 [P < 0.00000] vs. 0.2 [P = 0.011]). CONCLUSIONS: Symptomatic colloid cysts are more likely to develop hydrocephalus and sudden acute deterioration. The colloid cyst risk score is a step towards objective decision making, with scope for modification such as the one that we have attempted with new zone classification to achieve superior prognostic ability.

Isolated entrapment of the lateral ventricle after neuroendoscopic resection of colloid cysts: single - center experience and management.

BACKGROUND: A minimally invasive option of colloid cyst surgical treatment is endoscopic resection, well validated in various reports and clinical practice. A rare complication of the surgical treatment, previously reported only once in literature, is the entrapment of the lateral ventricle. In this study we aim to outline our experience in the management of this occurrence, hypothesizing possible etiopathogenetic causes. METHODS: Among patients who underwent neuroendoscopic resection for a colloid cysts at our Institution between 2013 and 2022, cases who developed a postoperative lateral ventricle entrapment were retrospectively reviewed and included. Clinical history, imaging and treatment were reported. RESULTS: Among 34 patients treated for a colloid cysts, two (5.9 %) patients developed an ipsilateral ventricular entrapment with dilation from two to five months after the resection. Both patients were substantially asymptomatic and neurologically intact, and therefore treated conservatively. One case underwent complete spontaneous radiological resolution one month later, and the other one has remained neurological asymptomatic at follow-up. CONCLUSIONS: Isolated asymptomatic ventricular entrapment with significant dilation after endoscopic colloid cyst resection is a rare occurrence which can be plausibly caused by scar tissue at the level of the foramen of Monro. Because they can have an indolent course with spontaneous resolution, conservative treatment is a viable option, with strict radiological and clinical follow - up. Given the rarity of the occurrence, further studies with larger cohorts are warranted to confirm the etiopathogenetic hypothesis and validate the clinical management.

Isolated Intraventricular Neurocysticercosis: Atypical Presentation of a Colloid Cyst.

Neurocysticercosis is a condition characterized by the presence of Taenia solium (larval stage: Cysticercus cellulosae) in the brain and is classified as a tropical disease. Although it was previously uncommon in Europe, the number of cases has been increasing over the past decade. In this report, we present a case of a patient who was admitted with symptoms of raised intracranial pressure and biventricular hydrocephalus, without evidence of infection. Imaging studies revealed the presence of an atypical colloid cyst, which was subsequently removed using a neurosurgical endoscopic approach. Anatomopathologic analysis confirmed the presence of a C. cellulosae larva. It is crucial not to overlook or misdiagnose isolated intraventricular neurocysticercosis because it can lead to complications such as delayed diagnosis and dissemination of the cyst.

Endoscopic trans-septal interforniceal approach for excision of colloid cysts of the third ventricle using the rotational technique.

Colloid cysts of the third ventricle are benign intracranial lesions that account for 0.5 to 2% of all brain tumors and are even rarer in pediatric population. Dandy was the first to successfully excise a colloid cyst of the third ventricle via a transcortical transventricular approach in 1921. For several decades to follow, the transcortical transventricular and transcallosal microsurgical approaches remained the cornerstone of surgical management of these lesions. With time and refinements in endoscopic equipment and techniques, endoscopic resection of colloid cysts evolved into a currently well-established and appealing minimally invasive alternative to microsurgery. Endoscopic endochannel techniques for colloid cysts of the third ventricle may either be transforaminal or trans-septal interforniceal, depending on the pathoanatomical features of the colloid cyst and its relation to the juxtaposed anatomical structures. The endoscopic trans-septal interforniceal approach is required to access the rare subset of colloid cysts that extend superior to the roof of the third ventricle between the two fornices insinuating themselves between the leaflets of the septum pellucidum. In this article, the surgical technique of the endochannel endoscopic trans-septal interforniceal approach is elaborated upon. A representative case is presented along with an operative video.

Endoscopic ultrasonic aspirator-assisted removal of a third ventricular colloid cyst.

BACKGROUND: Colloid cysts are benign tumors usually located on the roof of the third ventricle. Cyst removal is the treatment of choice. It can be accomplished microsurgically through a transcortical- or transcallosal approach, or endoscopically. There is a lack of consensus regarding the best strategy for cyst removal. One of the challenges of the traditional endoscopic technique is dealing with the cyst content density. Hyperdensity on computed tomography scan and low signal on T2-weighted magnetic resonance imaging (MRI) cyst are correlated with high viscosity cystic content. CASE REPORTS: We present a case of a colloid cyst of the third ventricle in a 15-year-old boy removed through a pure endoscopic transventricular approach. The cyst presented a low signal on T2 MRI; nevertheless, it was easily removed with the help of an endoscopic ultrasonic aspirator. DISCUSSION AND CONCLUSION: The colloid cyst of the third ventricle can be safely treated by a purely endoscopic approach. The rationale of the use of the ultrasonic aspirator relies on the facilitation of aspiration of the content even when the consistency is extremely firm.

Practical, Stereotactic, Low-Profile Technique for Transcortical/Transventricular Colloid Cyst Removal Independent of Ventricular Size: Technical Note and Analysis of Approaches.

BACKGROUND: In the presence of a dilated foramen of Monro, a transcortical, transforaminal approach is considered the safest and simplest approach for resection of colloid cysts. However, in the presence of small or normal frontal horns, numerous microsurgical approaches and, often complicated, variations have been described, invariably employing forms of stereotactic navigation. OBJECTIVE: To report an alternative, accurate, microsurgical stereotactic low-profile technique. METHODS: The small frontal horn is stereotactically targeted as previously described. Routine equipment is used to accurately create a novel, rigid, atraumatic surgical corridor. RESULTS: After a 7-mm corticotomy, a peel-away catheter carrying the AxiEM stylet engages the target set as the frontal horn. All joints of the endoscope holder are locked, allowing only catheter advancement (y axis) while lateral (x axis) or anteroposterior (z axis) movements are secure. Two, 7-mm retractor blades are inserted. The extremely consistent anatomy of the foramen of Monro allows en bloc microsurgical removal without unnecessary coagulation of cyst wall or choroid plexus. CONCLUSION: Despite a plethora of approaches to the rostral third ventricle, in the presence of normal or small frontal horns, including creation of transcallosal/interforniceal, suprachoroidal (or transchoroidal), and sub-choroidal, colloid cyst resection does not necessarily need to be convoluted. Technical nuances of an accurate, practical, minimally invasive technique are described.

On Natural History and Management of Colloid Cysts: Time to Rethink?

BACKGROUND: Colloid cysts, although benign, may occasionally cause obstructive hydrocephalus and sudden death. Reliable prognostic factors for symptomatic progression have been sought, with heterogenous results. METHODS: We conducted a retrospective review of all cases of colloid cysts of the third ventricle managed at our center between 2009 and 2019. Clinical and neuroimaging characteristics were analyzed using logistic regression in relation to symptomatic status and hydrocephalus. The cutoff values for outcome prediction were calculated using the receiver operating characteristic curve analysis. RESULTS: There were 82 patients with colloid cysts, of whom 60 were asymptomatic and 22 symptomatic. None of the asymptomatic patients experienced acute neurologic decline or hydrocephalus during follow-up, whereas half (n = 11) of the symptomatic patients presented with hydrocephalus, 8 of whom had acute hydrocephalus. We found 3 putative candidate risk factors for symptomatic colloid cysts: T1-weighted magnetic resonance imaging hyperintense/mixed signal appearance (P = 0.004), location in risk zone I (P = 0.007), and a volume >236.49 mm3 (P = 0.007). Cyst diameter and volume/foramen of Monro diameter ratios had a decreasing trend over time among asymptomatic patients, providing new insights into the natural history of the disease. CONCLUSIONS: Only a few asymptomatic colloid cysts showed progression requiring surgery, with no acute deterioration or fatal events, whereas the rest remained stable over time, thus supporting a more conservative approach for this group of patients. Higher risk for developing symptomatic colloid cyst was defined by a risk score that included T1-weighted magnetic resonance imaging appearance, risk zone, and colloid cyst volume, aiding the detection of patients at risk of clinical deterioration.

Acute diffuse cerebral vasospasm as a complication of endoscopic resection of a colloid cyst: a case report.

BACKGROUND: Endoscopic resection can be used for removing colloid cysts as a substitute for open craniotomy. Cerebral vasospasm, a possible complication of the craniotomy procedure, has not been reported as a complication of endoscopic removal of colloid cysts. CASE DESCRIPTION: A 58-year-old man developed the worst headache of his life. The CT and MRI showed a 1.3 cm midline third ventricular cyst at the level of the foramen of Monro, consistent with a colloid cyst. The patient elected to undergo an endoscopic resection of the colloid cyst. The image-guided frameless stereotactic endoscopic colloid cyst resection proceeded without events. Postoperative MRI showed a gross total resection. The patient continued to improve until post-operative day #9 when he experienced an episode of slurred speech and several episodes of legs buckling. An MRI did not show a stroke. A CT angiogram showed diffuse vasospasm, including the basilar artery and bilateral middle cerebral arteries, when compared to the patient's preoperative MRA. The patient's antihypertensive medications were stopped. The patient was started on Nimodipine, 60 mg every 4 hours, and triple H therapy (Hypertension, Hypervolemia, and Hemodilution) was applied. His blood pressure rose and his neurologic exam improved over several days. The patient returned to his baseline in 14 days without any neurological deficits. To our knowledge, this is the first case report of a patient undergoing endoscopic colloid cyst resection that was complicated by diffuse cerebral vasospasm. CONCLUSIONS: We report the first case of acute, transient cerebral vasospasm following endoscopic resection of a colloid cyst.

Disease characteristics and patterns of familial colloid cyst of the third ventricle: An international survey of the Colloid Cyst Survivors Group.

BACKGROUND: Colloid cysts of the third ventricle are rare benign tumors, accounting for approximately 1% of all intracranial tumors. Familial colloid cysts are less common, only 25 cases have been previously reported in the literature. We aim to describe demographic and disease-specific characteristics to reduce the knowledge gap with this potentially life-threatening tumor. METHODS: We conducted a retrospective cohort study of 211 colloid cyst patients from the Colloid Cyst Survivors Group who completed a survey that included demographicandclinical data andinquired aboutfamily members diagnosed with a colloid cyst. Datawascollected from October 14th, 2021 to October 27th, 2021. We compared our data with previously published cases from the literature. RESULTS: A total of 211 responses from patients with a previous diagnosis of a colloid cyst completed our survey. 11.8 % were familial colloid cysts, of this group 60.8 % were symptomatic and 39.2 % incidental. We observed significant difference between symptom incidence between reports from the literature and our cohort: headache 75.5 % versus 49 % (p = 0.005); imbalance 13.2 % versus 31.4 % (p = 0.03); nausea 11.3 % versus 29.4 % (p = 0.02), and difficulty walking 1.9 % versus 19.6 % (p = 0.003). Additionally, we found first degree family member as the most frequent relative diagnosed with this disease. CONCLUSION: Our study involved the largestcohortof patients with familial colloid cysts. According to previous literature, siblings are the most prevalent family member affected by this disease, specifically among monozygotic twins. This suggests strong inheritance patterns and even genetic mechanism underlying the development of this disease.

Spontaneous regression of colloid cyst on the third ventricle: a case report with the review of the literature.

BACKGROUND: Colloid cyst (CC) is a rare and benign cyst found in the third ventricle near the foramen of Monro. Although the role of surgical resection is well established in symptomatic large-sized CC, it remains debatable whether surgical removal of CC with no symptoms or minimal symptoms is necessary. CASE PRESENTATION: A 49-year-old male patient visited our institute for incidentally detected intracranial mass. MRI demonstrated typical, 12 mm-sized CC located in the third ventricle. It was noticed that the cyst spontaneously decreased in size from 12 mm to 4 mm on MRI at 18 months after the first visit. CONCLUSION: Although spontaneous regression is a very rare phenomenon in CC, regular imaging study and frequent neurologic examination can be an alternative option for well-selected, asymptomatic cases.

Giant Colloid Cyst.

Giant colloid cysts are defined as cysts of more than 3 cm in maximal diameter. Few cases of giant colloid cysts have been reported in the literature. We herein describe a giant colloid cyst. A 15-year-old female presented with headache, blurred vision, and episodic behavioral changes for 3 months. Neurological examination was limited due to agitation and confusion. Fundoscopy was notable for bilateral papilledema. Brain computed tomography revealed a giant third-ventricular lesion, causing obstructive hydrocephalus. The patient underwent urgent ventriculoperitoneal shunt insertion initially and then cyst excision. The histopathological sections of the lesion were compatible with a colloid cyst. Five years following surgical resection, a brain magnetic resonance imaging did not demonstrate any evidence of residual or cyst recurrence. To our knowledge, giant colloid cysts have been rarely reported and pose a management dilemma in the literature. The present article highlights the symptomatology, radiological findings, and outcome of a giant colloid cyst.