Intraventricular Tumors: Surgical Considerations in Lateral and Third Ventricular Tumors.

Management of lateral and third ventricular tumors has been a challenge for neurosurgeons. Advances in imaging and pathology have helped in a better understanding of the treatment options. Technical refinement of microsurgical technique and addition of endoscopy has enabled more radical excision of tumors, when indicated, and added more safety.A proper understanding of the pathology at various ages and treatment options is continuously evolving. Many pediatric tumors are amenable to conservative surgical methods with effective complementary treatments. However, radical surgery is required in many adults as the main treatment and for many benign tumors. Various intraventricular lesions encountered and their surgical management is reviewed here for their efficacy, safety, and outcome, encompassing changes in our practice over the last 20 years.

The occipital interhemispheric transtentorial approach in infants and toddlers: efficacy and complications.

INTRODUCTION: Outcomes for pineal region and superior cerebellar tumors in young children often hinge on extent of microsurgical resection, and thus choosing an approach that provides adequate visualization of pathology is essential. The occipital interhemispheric transtentorial (OITT) approach provides excellent exposure while minimizing cerebellar retraction. However, this approach has not been widely accepted as a viable option for very young children due to concerns for potential blood loss when incising the tentorium. The aim of this paper is to characterize our recent institutional experience with the occipital interhemispheric transtentorial approach (OITT) for tumor resection in infants and toddlers. METHODS: A retrospective study was performed between 2016 and 2023 of pediatric patients less than 36 months of age who underwent OITT for tumor resection at a high-volume referral center. Patients with at least 3 months of postoperative follow-up and postoperative MRI were included. Primary outcomes included extent of resection, intraoperative and postoperative complications, and neurologic outcome. Secondary outcomes included length of stay and estimated blood loss. RESULTS: Eight patients, five male, were included. The median age at the time of surgery was 10 months (range 5-36 months). Presenting symptoms included macrocephaly, nausea/vomiting, strabismus, gait instability, or milestone regression. Hydrocephalus was present preoperatively in all patients. Average tumor volume was 38.6 cm3, ranging from 1.3 to 71.9 cm3. All patients underwent an OITT approach for tumor resection with stereotactic guidance. No intraoperative complications occurred, and no permanent neurologic deficits developed postoperatively. Gross total resection was achieved in all cases per postoperative MRI report, and no instances of new cerebellar, brainstem, or occipital lobe ischemia were noted. CONCLUSIONS: OITT approach for tumor resection in very young children (≤ 36 months) is an effective strategy with an acceptable safety profile. In our series, no significant intraoperative or postoperative complications occurred. To our knowledge, this is the first report describing this technique specifically in patients less than 36 months of age.

The occipital interhemispheric transtentorial approach: historical perspective and evolution over time.

PURPOSE: Access to the pineal region has always represented a fascinating challenge to the neurosurgeons. Almost equally thrilling is the historical evolution from the hard beginnings with extremely high mortality rates to the current surgical outcomes, with excellent resection rates without long-term morbidity for most of the patients. The purpose of this paper is to provide an overview of the historical evolution of the occipital interhemispheric transtentorial (OITT) approach and its role in the development of access to the pineal region. METHODS: Review of the literature highlights the occipital transtentorial approach from the historical context prior its description and the beginning to the current modifications and new recent insights. RESULTS: The occipital transtentorial approach described initially by Poppen in 1966 has played a key role in the progress and success accessing the pineal area. CONCLUSION: This historical review aims to highlight the extraordinary effort of those neurosurgeons who guided and led the development of one of the most important approaches to the pineal region.

Supracerebellar Infratentorial Approach, Indications, and Technical Pitfalls.

Posterior tentorial incisura not infrequently requires to be exposed for tumors of pineal gland, pulvinar, midbrain and cerebellum, aneurysms, arteriovenous malformations. Residing almost at the center of the brain, this area is almost equal distance to any point on the calvarium behind coronal sutures enabling alternative routes to encounter. Compared to supratentorial routes either subtemporal or suboccipital approach, infratentorial supracerebellar route has several advantages as providing shortest, most direct approach to the lesions of this area without encountering any important arteries and veins. Since its initial description at the early twentieth century, a wide range of complications arising from cerebellar infarction, air embolism, and neural tissue damage have been encountered. Working in a deep, narrow corridor without enough illumination and visibility under very limited anesthesiology support hindered popularization of this approach. In the contemporary era of neurosurgery, advanced diagnostic tools and surgical microscopes with state-of-the-art microsurgery techniques coupled with modern anesthesiology have eliminated almost all drawbacks of infratentorial supracerebellar approach.

Fully endoscopic occipital transtentorial approach for pineal region tumors.

PURPOSE: Aggressive surgical resection for pineal region tumors, which is a mainstay of management in almost all cases, remains technically challenging because these tumors are located at the geometric center of the brain and surrounded by critical neurovascular structures. Therefore, any refinement in the surgical procedure is desirable. We have recently introduced an endoscope to the occipital transtentorial approach (OTA), which has been one of the most common procedures for reaching the pineal region, to overcome some of the disadvantages of the procedure, including the necessity of a relatively large skin incision and bone opening, the difficulty in orientation due to the obliqueness of the approach, the possibility of retraction injury on the occipital lobe and the corpus callosum, and blind spots at the ipsilateral wall and the roof of the third ventricle. METHODS: We performed endoscopic OTA with corresponding advantages, including less invasiveness by virtue of a small entrance limiting the retraction of the occipital lobe, the elimination of blind spots, and the facilitation of fine manipulation based on the bright endoscopic view even at substantial depth, which is panoramic and can be magnified as needed. This procedure was substantially different from a conventional microscopic OTA, though both use a similar corridor. To maximize maneuverability within the limited space in endoscopic OTA, it was necessary to thoroughly understand each step of the procedure, as well as optimal sequence in the procedure. RESULTS AND CONCLUSION: We found endoscopic OTA to be a promising technique for resectioning pineal region tumors, with the potential for extensive and routine application for surgeons familiar with endoscopic surgery.

Second-look surgery for pineal region tumors.

PURPOSE: Surgical resection of pineal region tumors is challenging because of close proximity to the vein of Galen draining system and the quadrigeminal plate. Surgical resection usually is performed through the narrow corridor by piecemeal resection and en bloc resection is difficult in cases of large tumors. Moreover, in cases of hypervascular tumors, surgical resection through the narrow corridor could entail massive intraoperative bleeding. The effectiveness of neoadjuvant chemotherapy and second-look surgery for pineal region tumors for maximal safe resection was evaluated. METHODS: Retrospective institutional review of pediatric patients with pineal region tumors who underwent second look surgery after neoadjuvant chemotherapy was performed. RESULTS: Nine patients underwent surgical resection after neoadjuvant chemotherapy over the period of September 2017 to February 2022. The mean age was 7.7 years (ranged from 1.4 to 15.3 years). Three patients underwent partial resection via open craniotomy, and 6 underwent endoscopic biopsy as an initial surgery. The histopathological diagnoses were germ cell tumors in 5 patients (yolk sac tumors in 2, germinoma in 2, choriocarcinoma in 1), /rhabdoid tumor (AT/RT) in 2, medulloblastoma in 1, and high-grade glioneuronal tumor in 1. After several courses of chemotherapy, the second-look surgery was performed. The tumor volume was reduced in 8 patients (89%) after chemotherapy except for 1 case of growing teratoma syndrome. The tumor was extended laterally to the ambient cistern in 2 patients, and posteriorly to the tentorial surface of the cerebellum in 3 patients. The lesion was approached through occipital transtentorial approach in 8 patients and infratentorial supracerebellar approach in 1. Intraoperatively, the high vascularity of the tumor was not observed in all cases. Gross total resection (8 patients, 89%) or near total resection (1, 11%) was achieved in all cases. No complications were observed postoperatively in all cases. Eight patients subsequently underwent additional chemo-radiation therapy according to the initial diagnosis. All patients are alive with no evidence of recurrence with a mean follow-up of 33 months. CONCLUSIONS: Neoadjuvant chemotherapy and second-look surgery for pediatric pineal region tumors was considered to be effective in reducing the tumor volume and vascularity, which facilitates the safe maximal tumor resection.

Pediatric pineal region masses: a single-center experience over 25 years.

PURPOSE: Pineal region tumors (PRT) represent less than 1% of brain neoplasms. The rare and heterogeneous nature of these tumors is reflected in the variety of treatment modalities employed. METHODS: A single-center retrospective review of all pediatric patients with pineal region tumors between November 1996 and June 2021 was performed. Fifty-six cases of pineal tumors were reviewed for age and symptoms upon presentation, diagnostic methods, imaging characteristics, histological classification, treatment modalities, recurrence, and mortality rates. RESULTS: The average age at diagnosis was 11.3 years. The majority of patients were male (82.1%) and Caucasian (73.2%). The most common presenting symptoms were headache (n = 38, 67.9%) and visual problems (n = 34, 60.7%). Hydrocephalus was present in 49 patients (87.5%). Germinoma (n = 20, 35.7%) and non-germinomatous germ cell tumor (NGGCT) (n = 17, 30.4%) were the most common tumors. Chemotherapy was employed for 54 patients (96.4%), radiation for 49 (87.5%), and surgical resection for 14 (25.0%). The average duration of treatment was 5.9 months. Progression-free survival was 74.4% at 5 years and 72.0% at 10 years. Overall survival was 85.7% at 5 years and 77.1% at 10 years. CONCLUSION: Treatment of pineal region tumors must be targeted to each patient based on presentation, subtype, presence of hydrocephalus, and extent of disease. Upfront surgical resection is usually not indicated. As advances in oncological care proceed, treatment modalities may continue to improve in efficacy.

Pineal/germ cell tumors and pineal parenchymal tumors.

INTRODUCTION: Pineal region tumors (PRTs) are tumors arising from the pineal gland and the paraspinal structures. These tumors are rare and heterogeneous that account for 2.8-10.1% and 0.6-3.2% of tumors in children and in all ages, respectively. Almost all types and subtypes of CNS tumors may be diagnosed in this region. These tumors come from cells of the pineal gland (pinealocytes and neuroglial cells), ectopic primordial germ cells (PGC), and cells from adjacent structures. Hence, PRTs are consisted of pineal parenchyma tumors (PPTs), germ cell tumors (GCTs), neuroepithelial tumors (NETs), other miscellaneous types of tumors, cystic tumors (epidermoid, dermoid), and pineal cyst in addition. The symptoms of PRTs correlate to the increased intracranial cranial pressure due to obstructive hydrocephalus and dorsal midbrain compression. The diagnostic imaging studies are mainly MRI of brain (with and without gadolinium) along with a sagittal view of whole spine. Serum and/or CSF AFP/ß-HCG helps to identify GCTs. The treatment of PRTs is consisted of the selection of surgical biopsy/resection, handling of hydrocephalus, neoadjuvant and/or adjuvant therapy according to age, tumor location, histopathological/molecular classification, grading of tumors, staging, and threshold value of markers (for GCTs) in addition. METHODS: In this article, we review the following focus points: 1. Background of pineal region tumors. 2. Pineal GCTs and evolution of management. 3. Molecular study for GCTs and pineal parenchymal tumors. 4. Review of surgical approaches to the pineal region. 5. Contribution of endoscopy. 6. Adjuvant therapy (chemotherapy, radiotherapy, and combination). 7. RESULTS: In all ages, the leading three types of PRTs in western countries were PPTs (22.7-34.8%), GCTs (27.3-34.4%), and NETs (17.2-28%). In children and young adults, the leading PRTs were invariably in the order of GCTs (40-80.5%), PPTs (7.6-21.6%), NETs (2.4-37.5%). Surgical biopsy/resection of PRTs is important for precision diagnosis and therapy. Safe resection with acceptable low mortality and morbidity was achieved after 1970s because of the advancement of surgical approaches, CSF shunt and valve system, microscopic and endoscopic surgery. Following histopathological diagnosis and classification of types and subtypes of PRTs, in PPTs, through molecular profiling, four molecular groups of pineoblastoma (PB) and their oncogenic driver were identified. Hence, molecular stratified precision therapy can be achieved. CONCLUSION: Modern endoscopic and microsurgical approaches help to achieve precise histopathological diagnosis and molecular classification of different types and subtypes of pineal region tumors for risk-stratified optimal, effective, and protective therapy. In the future, molecular analysis of biospecimen (CSF and blood) along with AI radiomics on tumor imaging integrating clinical and bioinformation may help for personalized and risk-stratified management of patients with pineal region tumors.

The surgical intervention for pineal region tumors.

Histological and molecular characterization is essential for the diagnosis of pediatric brain tumors. In the pineal region tumors, it is necessary to remove a sufficient tumor volume to make a diagnosis. However, surgery in this region is challenging due to its deep anatomical location and surrounded by critical structures and complex venous system. Knowledge of the anatomy and function of the pineal region and tumor histological types is imperative for the successful management of pineal region tumors. This article describes surgical approaches to pineal tumors, focusing on the occipital transtentorial approach and adding the author's experience to what has been known in the literature. Recent innovations have made this approach more popular and can be applied to occipital fossa lesions.

Pediatric pineal region tumors: institutional experience of surgical managements with posterior interhemispheric transtentorial approach.

PURPOSE: Resecting pineal region tumors in children is often challenging. Several approaches have been proposed and practiced. A personal series of pediatric pineal region tumors resected through craniotomy with posterior interhemispheric occipital transtentorial (OT) approach are reviewed. We present the surgical techniques, pitfalls, and their results. MATERIAL AND METHODS: Eighty patients ranging in age from 3 months to 21 years old, and treated over 3 decades were reviewed. Hydrocephalus caused the main presenting symptoms and was noted in 74 patients. It was treated prior to the craniotomy for tumor resection with endoscopic third ventriculostomy (ETV) in 33, external ventricular drainage in 26, and precraniotomy shunt in 15. Nine patients had ETV together with endoscopic biopsy. All patients had a parieto-occipital craniotomy in a prone position. Through a tentorial section, a gross total resection of the tumor was attempted except for germinomas. RESULTS: The tumor pathology showed 32 germ cell tumors (GCT), 22 benign astrocytomas, 13 pineal parenchymal tumors, 5 ATRTs, 3 papillary tumors, and 5 others. Of GCTs, 18 were teratomas. The extent of resection consisted of 55 gross total resections, 13 subtotal resections, 10 partial, and 2 biopsies with one postoperative death. Hemiparesis in 2, cerebellar ataxia in another 2, and hemiballismus in 1 were transient and improved over time. One had permanent hemisensory loss and another patient had bilateral oculomotor palsy. Postoperative homonymous hemianopia occurred in 2 patients but subsided over a short period of time. Parinaud's sign was noted in 24 patients, of which 16 were transient. CONCLUSION: The posterior interhemispheric OT approach provides a safe route and comfortable access to the pineal region in children. A great majority of postoperative neurological complications are the results of direct manipulations of the midbrain at tumor resection. Identification and preservation of the tumor-brain interface are of paramount importance. GCTs other than teratomas are treated with neoadjuvant chemotherapy and may eliminate the need for craniotomy. Exophytic midbrain JPAs are amenable to resection.

Benign and Malignant Tumors of the Pineal Region.

Pineal region tumors fall into five broad categories: benign pineal region tumors, glial tumors, papillary tumors, pineal parenchymal tumors, and germ cell tumors. Genetic and transcriptional studies have identified key chromosomal alterations in germinomas (RUNDC3A, ASAH1, LPL) and in pineocytomas/pineoblastomas (DROSHA/DICER1, RB1). Pineal region tumors generally present with symptoms of hydrocephalus including nausea, vomiting, papilledema, and the classical Parinaud's triad of upgaze paralysis, convergence-retraction nystagmus, and light-near pupillary dissociation. Workup requires neuroimaging and tissue diagnosis via biopsy. In germinoma cases, diagnosis may be made based on serum or CSF studies for alpha-fetoprotein or beta-HCG making the preferred treatment radiosurgery, thereby preventing the need for unnecessary surgeries. Treatment generally involves three steps: CSF diversion in cases of hydrocephalus, biopsy through endoscopic or stereotactic methods, and open surgical resection. Multiple surgical approaches are possible for approach to the pineal region. The original approach to the pineal region was the interhemispheric transcallosal first described by Dandy. The most common approach is the supracerebellar infratentorial approach as it utilizes a natural anatomic corridor for access to the pineal region. The paramedian or lateral supracerebellar infratentorial approach is another improvement that uses a similar anatomic corridor but allows for preservation of midline bridging veins; this minimizes the chance for brainstem or cerebellar venous infarction. Determination of the optimal approach relies on tumor characteristics, namely location of deep venous structures to the tumor along with the lateral eccentricity of the tumor. The immediate post-operative period is important as hemorrhage or swelling can cause obstructive hydrocephalus and lead to rapid deterioration. Adjuvant therapy, whether chemotherapy or radiation, is based on tumor pathology. Improvements within pineal surgery will require improved technology for access to the pineal region along with targeted therapies that can effectively treat and prevent recurrence of malignant pineal region tumors.

Microscope neuronavigation-guided microsurgical fenestration of quadrigeminal cistern arachnoid cysts: how I do it.

BACKGROUND: Management options for treatment of quadrigeminal arachnoid cysts (QAC) include microsurgical/endoscopic fenestration or shunt. There is an open debate about which method is the best. Microsurgical fenestration is well suited for treatment of QAC with predominant infratentorial component and without hydrocephalus making endoscopic procedures more challenging. METHOD: We describe the microsurgical technique and related anatomy to fenestrate infratentorial QAC through supracerebellar infratentorial approach. We also discuss our experiences with this approach, some of the drawbacks and nuances. CONCLUSION: Navigation-guided microsurgical fenestration of infratentorial QAC is the authors' surgical approach of choice for treating these rare challenging lesions when not associated with hydrocephalus.

Paediatric atypical teratoid/rhabdoid tumour of the pineal region mimicking a meningioma: a case report and literature review.

PURPOSE: Atypical teratoid/rhabdoid tumour (AT/RT) is a highly malignant central nervous system tumour of early childhood. According to the latest WHO classification, the diagnosis of AT/RTs needs to be confirmed by the absence of SMARCB1 (INI1) or SMARCA4 (BRG1) protein expression. AT/RT in the pineal region is infrequent and most have not been proven genetically. Here, we report a case of AT/RT in the pineal region, preoperatively misdiagnosed as a meningioma. Immunohistochemistry revealed the absence of INI1 protein expression. METHOD: A 29-month-old boy was admitted to the hospital after 14 days of emotional apathy and a 2-day vomiting history. AT/RT was not considered during the initial diagnosis because this tumour is rare in this region and is often accompanied by cystic degeneration and necrosis on imaging. Subsequently, the patient underwent surgery and the tumour was completely excised. RESULT: The pathological diagnosis was AT/RT. After discharge, the patient continued chemotherapy in other hospitals but died five months after surgery because of disease progression. CONCLUSION: To our knowledge, this is the fifth case of paediatric pineal AT/RT confirmed genetically. Although in children AT/RT in the pineal gland is rare, a differential diagnosis of AT/RT should be considered when new pineal masses appear in children. For this highly malignant disease with poor prognosis, it is very important to detect and recognize the disease as soon as possible, and to adopt surgery plus multiple treatment management.

Long term outcomes following surgery for pineal region tumors.

PURPOSE: Pineal region tumors are surgically demanding tumors to resect. Long term neuro-oncologic outcomes following surgical excision of tumors from this region have been underreported. We sought to define the long term outcomes of patients undergoing resection of pineal region tumors. METHODS: A retrospective analysis of a prospectively maintained database was performed on patients who underwent intended surgical excision of pineal region tumors. Overall survival (OS) and progression free survival (PFS) were the primary endpoints of this study. Factors associated with OS, PFS and the degree of resection were analyzed, along with 30-day complication rates and dependence on CSF diversion. RESULTS: Sixty-eight patients with a mean age of 30.9 ± 15.3 years were analyzed. The median clinical and radiographic follow-up was 95.7 and 48.2 months, respectively. The supracerebellar infratentorial and the occipital transtentorial corridors were utilized in the majority of cases (80.9%). The gross total resection (GTR) rate was 52.9% (n=36). The 5-year OS and PFS rates were 70.2% and 58.5%, respectively. Achieving GTR was associated with improved OS (HR 0.39, p = 0.03) and PFS (HR 0.4, p = 0.006). The 30-day mortality rate was 5.9%. The need for CSF diversion was high with 77.9% of patients requiring a shunt or ETV by last follow-up. CONCLUSIONS: This is the first modern surgical series providing long term follow-up for patients undergoing surgical resection of pineal region tumors. Obtaining a GTR of these challenging tumors is beneficial with regards to PFS/OS. Higher grade tumors have diminished PFS/OS and are treated with adjuvant chemotherapy and/or radiotherapy.

Characterization of high-grade pineal region lesions: the usefulness of apparent diffusion coefficient volumetric values.

BACKGROUND: High-grade pineal region tumors are rare and heterogeneous types of primary central nervous system neoplasms; radiological differential diagnosis is challenging but it is important because it has a therapeutic relevance. PURPOSE: To discriminate among high-grade pineal region tumors by combining apparent diffusion coefficient (ADC) volumetric values and qualitative features in order to predict their histology. MATERIAL AND METHODS: Twenty-two patients with high-grade pineal region tumors were assessed by qualitative and quantitative analysis. Margins, T2-weighted signal intensity, contrast enhancement, hemorrhage, calcifications, different volumetric ADC fractions (ADCmean, ADCmax, ADCmin) were evaluated and were compared to the histopathologic findings (cell count and proliferation index). RESULTS: Our qualitative imaging data showed that only margins were different among different tumors and each tumor type showed peculiar age onset. ADCmean was found the best quantitative value to discriminate high-grade tumors of the pineal region. ADCmean correlated with proliferation index but not with cell count. ADCmean values were lower in tumors with higher proliferation rate and a significant difference in ADCmean values were found between germinomas and pineoblastomas, between germinomas and papillary tumors and between papillary tumors and pineoblastomas. Moreover, the cut-off value of 0.865 × 10-3 mm2/s for ADCmean (ADC mean threshold value) could differentiate germinoma from pineoblastomas with the best combination of sensitivity and specificity. CONCLUSION: The ADCmean value measured on the whole tumor, reflecting tumor proliferative activity, may be a practical and non-invasive marker for predicting tumor histology in high-grade pineal region lesions and might be useful in preoperative assessment.

The precuneal interhemispheric, trans-tentorial corridor to the pineal region and brainstem, surgical anatomy, and case illustration.

BACKGROUND: The pineal region and dorsal midbrain are among the most challenging surgical targets. To approach lesions in this region that harbor a superior to inferior long axis, we describe the basic steps of the precuneal, interhemispheric, trans-tentorial approach and illustrate anatomical landmarks of this established, but not so popular, surgical trajectory. METHOD: To study the anatomical landmarks and safety of this approach, the neurovascular anatomy was studied on 22 sides of 11 formalin-fixed latex-injected anatomical specimens. A step-by-step dissection of the precuneal interhemispheric trans-tentorial approach and study of the key anatomical landmarks was performed. An illustrative clinical case of a pontomesencephalic cavernous malformation (CM) resected through this approach is also detailed. RESULTS: The mean distance from the transverse sinus to the most posterior cortical vein draining into the superior sagittal sinus was 6.4 cm. The mean distance from the calcarine sulcus to the most posterior cortical vein was 5.3 cm. Key steps of the dissection are as follows: craniotomy exposing the posterior aspect of the superior sagittal sinus (SSS), durotomy and gentle retraction of the SSS edge, dissection of the interhemispheric fissure, linear incision of the tentorium that extends anteriorly to the incisura and lateral reflection of the tentorium, and arachnoidal dissection and exposure of the cerebellomesencephalic fissure. CONCLUSION: The precuneal, interhemispheric, trans-tentorial approach affords excellent access to the falcotentorial junction, splenium, pineal region, quadrigeminal cistern, and dorsal pons once the cerebellomesencephalic fissure has been dissected.

A case of an atypical teratoid/rhabdoid tumor with distinctive histology in the pineal region in an adult patient.

A 31-year-old man suffered from headaches and presented at a hospital after the symptom worsened. Obstructive hydrocephalus and a pineal tumor were identified, and he was transferred to our hospital for further investigation and treatment. Cranial computed tomography revealed a hypodense mass lesion on the right of the pineal region, and calcifications and enlargement of the lateral and third cerebral ventricles were also evident. Blood tests were negative for all tumor markers. Laparoscopic biopsy and third-ventricle fenestration were performed that day as an emergency surgery to treat the obstructive hydrocephalus. Postoperative cranial magnetic resonance imaging revealed a solid tumor that was hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging, and heterogeneously enhanced by Gd. Subsequently, the tumor increased in size, and craniotomy and tumorectomy were performed. Histologically, the tumor proliferated as round or short spindle-shaped cells in a myxoid matrix, forming arrays that surrounded the blood vessels. As a few cells with eosinophilic cytoplasm were also present and immunostaining for INI-1 was negative, the patient was diagnosed with atypical teratoid/rhabdoid tumor (AT/RT). AT/RT of the pineal region in adults is rare, and herein, we report the morphological characteristics of this case and reviewed the relevant literature.

Pineal region tumors: an entity with crucial anatomical nuances.

PURPOSE: Intra-axial "pineal region" tumors include pineal, tectal, and aqueductal tumors. All three tumor subgroups cause obstruction of the aqueduct; however, they differ in radiological nuances, pathology, differential diagnosis, and treatment. The goal of this manuscript is to describe the radiological, clinical, and pathological nuances that differentiate between these subgroups. METHODS: All patients with intra-axial pineal region tumors were analyzed retrospectively, including demographics, radiological characteristics, pathology, treatment, and outcome. RESULTS: Forty-nine patients (1-69 years of age) were included: 19 pineal, 10 tectal, 10 aqueductal, 4 periaqueductal, and 6 complex. The 3 main subgroups differed in various radiological and anatomical nuances. Age and gender did not differ between groups. Other factors that did not differ between groups included T1 and T2 signals, presence of blood products, a normally located (non-displaced) tectum, anterior tectal displacement, thalamic involvement, and presence of hydrocephalus. The pathological spectrum differed between the 3 main subgroups, as well as the surgical treatment, and outcome. CONCLUSIONS: Despite sharing a close anatomical location, as well as all causing obstruction of the aqueduct with secondary hydrocephalus, the differential diagnosis, diagnostic methods, and possible treatment and surgical options differ between the various subgroups. Anatomical nuances are described to better delineate the various tumor subgroups and recommend specific treatment approaches.

Transcallosal-lateral ventricle-choroid fissure approach for excising large pineal region tumors extending into the third ventricle: experience in 15 pediatric cases.

Pineal region is deep located and tightly connected with surrounding important nerves, blood vessels, and other critical structure. Tumors in the regions are more commonly observed in children with complex pathology, difficult surgery, and poor prognosis. However, excision surgery on large tumor in the pineal region and extending into the third ventricle is characterized by high difficulty and uneasy treatment. Related experience and knowledge about excising large tumor in children pineal region which extending into the third ventricle by transcallosal-lateral ventricle-choroid fissure approach was described in the paper. Clinical data of 15 children patients with large tumors in pineal region which extending into the third ventricle treated by our group from 2011 to 2015 was retrospectively analyzed (< 15 years of age, tumor size > >3 × 3 × 3 cm3). Fifteen cases underwent tumor excision with surgery by transcallosal-lateral ventricle-choroid fissure approach including 11 male patients and 4 female patients with average age of 9.1 years and tumor volume from 3 × 3 × 3 to 5 × 6 × 7 cm3. They were assessed according to postoperative clinical symptom remission rate, blood loss during surgery, tumor removal rate, postoperative recurrence rate, etc. as indicators. Five cases belonged to germ cell tumors, 4 for teratoma, 1 for malignant teratoma, 2 for glioma, 2 for meningioma, and 1 for pineocytoma. Surgical total excision rate was 100%, while the mean intraoperative blood loss was about 300 ml. No case was dead due to surgery, and all cases had good postoperative recovery. Children patients are characterized by less blood than adults, larger volume size during surgery treatment, poor postoperative anti-infectious ability, etc. High requirements are proposed on surgery treatment, by long-term clinical exploration and experience accumulation. Our group believes that surrounding structures such as veins and dome are stretched and stimulated rarely in excision of children in large and medium tumor in pineal region which extending into the third ventricle by transcallosal-lateral ventricle-choroid fissure approach; thereby, the tumor can be completely excised, and larger veins and other important structures can be well-preserved with fewer complications, high full cut rate, and rapid recovery.

Endoscopic-assisted surgery versus microsurgery for pineal region tumors: a single-center retrospective study.

Pineal region tumors are extremely deep-seated and surgically challenging. The exposure and visualization obtained by microscopic surgery are relatively limiting. The application of high-definition endoscopes has recently provided neurosurgeons with a much more magnified and clearer view of the anatomy in the pineal region. The present study was performed to compare endoscopic-assisted surgery (ES) with microsurgery (MS) for pineal region tumors. We retrospectively analyzed patients admitted to our hospital for treatment of pineal region tumors from January 2016 to June 2019. All patients consented to undergo tumor resection with ES or MS. We compared the extent of resection, postoperative rate of hydrocephalus, complications, and outcomes between the two groups to estimate the safety and efficacy of ES. In total, 41 patients with pineal region tumors were divided into 2 groups: the ES group (n = 20) and MS group (n = 21). The rate of gross total resection was significantly higher in the ES than MS group (90.0% vs. 57.1%, p = 0.04). The rate of postoperative hydrocephalus was significantly lower in the ES than MS group (11.8% vs. 52.9%, p = 0.03). No significant differences were found in complications or the Karnofsky Performance Score between the two groups. ES can be used to safely and effectively achieve complete resection of pineal region tumors. In patients with obstructive hydrocephalus, ES provides a new way to directly open the aqueduct for cerebrospinal fluid recovery following tumor resection.