[Neurosurgical treatment of tumors of the pineal region - literature review and overview of cases at OMIII]. / A pineális régió tumorainak idegsebészeti ellátása ­ irodalmi áttekintés és az OMIII beteganyagának vizsgálata.

Pineal region tumors account for less than 1% of adult supratentorial tumors. Their treatment requires a multimodality approach. Previously, the treatment of choice was direct surgery, which is associated with high surgical risk. Advances in minimally invasive techniques and onco-radiotherapy offer a safe and multimodal personalized therapy. The aim of our study was to describe the practice of our Institute based on combined endoscopic and radiotherapy techniques. We performed a retrospective clinical study. We processed data from 23 adult patients who underwent endoscopic third ventricle fenestration and pineal tumor biopsy between 2014 and 2023. Descriptive statistics, t-test, Fisher's exact test and Kaplan-Meier analysis were performed. Clinical improvement with endoscopic intervention was achieved in 78.3% of cases. Significant increase in preoperative performance status was observed in the postoperative period (p=2.755e-5), and radiotherapy resulted in regression or stable disease. Our results suggest a safe treatment with good clinical outcome and an excellent alternative to direct surgery.

Papillary Tumors of Pineal Region: A Single-Center Experience in Management of 11 Cases.

BACKGROUND: Papillary tumors of pineal region (PTPR) comprise a very rare subset of pineal region tumors that have been recently described. Literature on the management and outcome of PTPR is scarce owing to the rarity of these tumors. To address this lacuna, we analyzed our experience in management of PTPR. METHODS: We retrospectively analyzed the outcome of 11 patients with histopathologically proven PTPR who underwent surgical excision at our center. RESULTS: Mean patient age was 33.3 years (range, 12-45 years), and male-to-female ratio was 1.75:1. Headache was the most common presentation followed by visual disturbances, altered sensorium, Perinaud syndrome, and seizures. Cerebrospinal fluid diversion was required in 6 patients. Krause approach was the most common approach used for tumor excision (9/11 cases). There was no perioperative mortality. Two patients were lost to follow-up. In the remaining 9 patients, the average follow-up period was 45 months (range, 12-79 months). On first postoperative magnetic resonance imaging, 8 patients showed no evidence of residual tumor (gross total resection), while 1 patient had small residual tumor (near-total resection) that remained stable during follow-up. Four patients underwent adjuvant chemoradiotherapy. None of the patients developed recurrence during follow-up. CONCLUSIONS: PTPR are a rare subgroup of pineal region tumors with distinct cells of origin but presentation similar to other pineal region tumors. Surgical resection constitutes the mainstay of management, and the extent of resection appears to be the most important determinant of prognosis. The role of adjuvant therapy still needs to be determined.

Microsurgical Treatment of Pineal Tumors: Anatomy and Techniques.

Pineal region tumors are challenging lesions in terms of surgical accessibility and removal.1 The complexity is compounded by the infrequency and heterogeneity of pineal neoplasms.2,3 In Video 1, we present the case of a 39-year-old woman who presented with progressive headaches and vision impairment. She underwent microsurgical resection for a pineal parenchymal tumor of intermediate differentiation. We discuss the rationale, risks, and benefits of treatment for this patient, as well as provide a detailed overview of the alternative approaches that may be considered. Additionally, we discuss the unique anatomic considerations for each approach and include a virtual reality-compatible 3-dimensional fly-through to highlight the relationship between the tumor and relevant venous anatomy. The patient tolerated the procedure well with excellent neurologic outcome, and her follow-up imaging showed no evidence of tumor recurrence.

Surgical corridor formation by minimally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach in pineal region tumor surgery: A review of 11 cases.

INTRODUCTION: The pineal region is a hard-to-reach part of the brain. There is no unequivocal opinion on the choice of a surgical approach to the pineal region. The surgical approaches described differ in both trajectory (infra- and supratentorial, interhemispheric) and size of craniotomy. They have advantages and disadvantages. The minimally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach we have described has all the advantages of the standard supratentorial approach and minimizes its disadvantages, namely, compression and contusion of the occipital lobe. The minimally invasive craniotomy and small surgical corridor facilitate that. METHODS: We describe 11 consecutive patients with various pineal region tumors (7 cases of pineal cysts, 2 cases of pinealocytoma, 1 case of medulloblastoma, and 1 case of meningioma) who were operated on in our hospital using the lateral OICST approach. Preoperative planning was performed using Surgical Theater®. The surgical corridor was formed using a retractor made from half of a syringe shortened according to the length of the surgical corridor. Preoperative lumbar drain was used. RESULTS: The pineal region tumors were completely resected in all cases. The mean craniotomy size was 2.22 × 1.79 cm. No long-term neurological deficits were reported. CONCLUSIONS: The use of semicircular retractors and intraoperative CSF drainage via a lumbar drain allows to form a small surgical corridor to the pineal region via minimally invasive craniotomy. This reduces traction and traumatization of the occipital lobe, as well as minimizes intra- and postoperative risks.

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.

Primary Gamma Knife Radiosurgery for pineal region tumors: A systematic review and pooled analysis of available literature with histological stratification.

Pineal region tumors (PTs) represent extremely rare pathologies, characterized by highly heterogeneous histological patterns. Most of the available evidence for Gamma Knife radiosurgical (GKSR) treatment of PTs arises from multimodal regimens, including GKSR as an adjuvant modality or as a salvage treatment at recurrence. We aimed to gather existing evidence on the topic and analyze single-patient-level data to address the efficacy and safety of primary GKSR. This is a systematic review of the literature (PubMed, Embase, Cochrane, Science Direct) and pooled analysis of single-patient-level data. A total of 1054 original works were retrieved. After excluding duplicates and irrelevant works, we included 13 papers (n = 64 patients). An additional 12 patients were included from the authors' original series. A total of 76 patients reached the final analysis; 56.5% (n = 43) received a histological diagnosis. Confirmed lesions included pineocytoma WHO grade I (60.5%), pineocytoma WHO grade II (14%), pineoblastoma WHO IV (7%), pineal tumor with intermediate differentiation WHO II/III (4.7%), papillary tumor of pineal region WHO II/III (4.7%), germ cell tumor (2.3%), neurocytoma WHO I (2.3%), astrocytoma WHO II (2.3%) and WHO III (2.3%). Presumptive diagnoses were achieved in the remaining 43.5% (n = 33) of cases and comprised of pineocytoma (9%), germ cell tumor (6%), low-grade glioma (6%), high-grade glioma (3%), meningioma (3%) and undefined in 73%. The mean age at the time of GKSR was 38.7 years and the mean lesional volume was 4.2 ± 4 cc. All patients received GKSR with a mean marginal dose of 14.7 ± 2.1 Gy (50% isodose). At a median 36-month follow-up, local control was achieved in 80.3% of cases. Thirteen patients showed progression after a median time of 14 months. Overall mortality was 13.2%. The median OS was not reached for all included lesions, except high-grade gliomas (8mo). The 3-year OS was 100% for LGG and pineal tumors with intermediate differentiation, 91% for low-grade pineal lesions, 66% for high-grade pineal lesions, 60% for germ cell tumors (GCTs), 50% for HGG, and 82% for undetermined tumors. The 3-year progression-free survival (PFS) was 100% for LGG and pineal intermediate tumors, 86% for low-grade pineal, 66% for high-grade pineal, 33.3% for GCTs, and 0% for HGG. Median PFS was 5 months for HGG and 34 months for GCTs. The radionecrosis rate was 6%, and cystic degeneration was observed in 2%. Ataxia as a presenting symptom strongly predicted mortality (odds ratio [OR] 104, p = .02), while GCTs and HGG histology well predicted PD (OR: 13, p = .04). These results support the efficacy and safety of primary GKSR treatment of PTs. Further studies are needed to validate these results, which highlight the importance of the initial presumptive diagnosis for choosing the best therapeutic strategy.

The sub-occipital transtentorial approach for pineal region tumors: how I do it.

BACKGROUND: Two major approaches exist for the surgical removal of pineal region tumors: the supracebellar infratentorial and the sub-occipital transtentorial. METHODS: We present the Lyon's technique of the sub-occipital transtentorial approach for pineal region tumors and our tricks to avoid complications. The principle is to expose the pineal region under the occipital lobe and not through the interhemispheric fissure. CONCLUSIONS: The sub-occipital transtentorial approach is a direct, extra cerebral, safe, and effective way to access tumors of the pineal region.

Neurosurgical application of pineal region tumor resection with 3D 4K exoscopy via infratentorial approach: a retrospective cohort study.

BACKGROUND: The pineal region tumors are challenging for neurosurgeons and can lead to secondary hydrocephalus. The introduction of the exoscope has provided clinical interventions with high image quality and an ergonomic system for pineal region tumor operations. In this study, the authors describe the exoscopic approach used to facilitate the surgical resection of pineal region tumors and relieve hydrocephalus. MATERIALS AND METHODS: In this retrospective cohort study, we consecutively reviewed the clinical and radiological data of 25 patients with pineal region lesions who underwent three-dimensional exoscopic tumor resection at a single center. RESULTS: The patient cohort consisted of 16 males and 9 females, with an average age of 34.6 years (range, 6-62 years; 8 cases aged ≤18). Pathological examination confirmed eight pineal gland tumors, four gliomas, nine germ cell neoplasms, two ependymomas, and two metastatic tumors. Preoperative hydrocephalus was present in 23 patients. Prior to tumor resection, external ventricular drainage (EVD) with Ommaya reservoir implantation was performed in 17 patients. Two patients received preoperative endoscopic third ventriculostomy (ETV), and five patients received a ventriculoperitoneal (VP) shunt, including one who received both procedures. Gross total resection was achieved in 19 patients (76%) in the 'head-up' park bench position using the exoscope. Eight patients (31.6%) with third ventricle invasion received subtotal resection, mainly in glioma cases, which was higher than those without invasion (0%), but not statistically significant ( P =0.278, Fisher's exact test). No new neurological dysfunction was observed after surgery. Two patients (8%) developed intracranial and pulmonary infections, and two patients (8%) suffered from pneumothorax. Hydrocephalus was significantly relieved in all patients postoperatively, and four patients with relapse hydrocephalus were cured during the long-term follow-up. Postoperative adjuvant management was recommended for indicated patients, and a mean follow-up of 24.8±14.3 months showed a satisfied outcome. CONCLUSIONS: The exoscope is a useful tool for pineal region tumor resection and hydrocephalus relief, particularly with posterior third ventricle invasion, as total resection could be achieved without obvious complication. The special superiority of the exoscope for the indicated pineal region tumors should be highlighted.

Radiation-induced Desmoid Tumor Development in the Radiotherapy Field in a Child With Pineoblastoma: A Case Report.

Although treatment-related secondary malignancies are rare, they are important problems after the treatment of childhood malignant diseases. Irradiation-induced sarcomas are the development of sarcoma different from the primary tumor after a latent period of ≥3 years or more in the radiotherapy field. Desmoid tumor is extremely rare as irradiation-induced tumor. A 7.5-year-old girl was referred to our hospital after a subtotal mass excision for a solid lesion with a cystic component located in the pineal gland. Pathologic examination revealed pineoblastoma. After surgery, craniospinal radiotherapy, and chemotherapy consisting of vincristine, cisplatin, and etoposide were performed. Painless swelling in the left parieto-occipital region ~75 months after the end of the treatment developed in the patient. A mass was detected in the intracranial but extra-axial region by radiologic imaging methods. Due to the total removal of the mass and the absence of a tumor in the surgical margins, she was followed up without additional treatment. The pathologic diagnosis was a desmoid tumor. She was followed up disease free for ~7 years after the primary tumor and ~7 months after the secondary tumor. Treatment-related desmoid tumor development after treatment for a central nervous system tumor in a child is extremely rare.

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.

Outcomes and surgical approaches for pineal region tumors in children: 30 years' experience.

OBJECTIVE: Pineal region tumors account for 2.7%-11% of all CNS tumors in children. In this series, the authors present their surgical results and long-term outcomes from a pediatric pineal region tumor cohort. METHODS: A total of 151 children aged 0-18 years were treated from 1991 to 2020. Tumor markers were collected in all patients; if positive, chemotherapy was performed, and if negative, biopsy was performed, preferably endoscopically. Resection was performed when there was a residual germ cell tumor (GCT) lesion after chemotherapy. RESULTS: The distribution based on histological type, as verified by markers, biopsy, or surgery, was germinoma (33.1%), nongerminomatous GCT (NGGCT) (27.2%), pineoblastoma (22.5%), glioma (12.6%), and embryonal tumor (atypical teratoid rhabdoid tumor) (3.3%). A total of 97 patients underwent resection, and gross-total resection (GTR) was achieved in 64%; the highest GTR rate (76.6%) was found in patients with GCTs, and the lowest (30.8%) was found in those with gliomas. The supracerebellar infratentorial approach (SCITA) was the most common, performed in 53.6% of patients, followed by the occipital transtentorial approach (OTA), performed in 24.7% of patients. Lesions were biopsied in 70 patients, and the diagnostic accuracy was 91.4. The overall survival (OS) rates at 12, 24, and 60 months as stratified by histological type were 93.7%, 93.7%, and 88% for patients with germinomas; 84.5%, 63.5%, and 40.7% for patients with pineoblastomas; 89.4%, 80.8%, and 67.2% for patients with NGGCTs; 89.4%, 78.2%, and 72.6% for patients with gliomas; and 40%, 20%, and 0% for patients with embryonal tumors, respectively (p < 0001). The OS at 60 months was significantly higher in the group with GTR (69.7%) than in the group with subtotal resection (40.8%) (p = 0.04). The 5-year progression-free survival was 77% for patients with germinomas, 72.6% for patients with gliomas, 50.8% for patients with NGGCTs, and 38.9% for patients with pineoblastomas. CONCLUSIONS: The efficacy of resection varies by histological type, and complete resection is associated with higher OS rates. Endoscopic biopsy is the method of choice for patients presenting with negative tumor markers and hydrocephalus. For tumors restricted to the midline and with extension to the third ventricle, a SCITA is preferred, whereas for lesions with extension toward the fourth ventricle, an OTA is preferred.

The parietooccipital interhemispheric transtentorial approach for pineal tumors.

Access to the pineal region has always been a challenge for neurosurgeons. The parietooccipital interhemispheric transtentorial approach is a slight variation of the traditional occipital transtentorial approach that provides adequate exposure to the lesions of the pineal region without introducing additional risks. In this study, the modified parietooccipital interhemispheric transtentorial approach is discussed including step-by-step anatomical cadaveric dissections and operative images. 27 adult patients (age > 18) who were operated over a 30-year period (1992-2022) by the senior author (M.N.P.) at two clinics, Marmara University, Department of Neurosurgery, Istanbul, Turkey and Acibadem Mehmet Ali Aydinlar University, Department of Neurosurgery, Istanbul, Turkey were analyzed. Only pineal region tumors were included in the analysis. Falcotentorial meningiomas and vascular lesions including cavernomas were excluded. 5 cadaveric specimens were dissected step by step following the surgical approach. Each step was documented using a Canon EOS 5D Mark II camera with Canon 100 mm Macro Lens. Step by step images of the dissections were presented including comparison with surgical images. Additional illustrations were used to describe the surgical corridor. The surgical corridor is maintained anterior to the parietooccipital sulcus along the medial of the precuneus. No retraction to the calcarine sulcus resulted in no postoperative hemianopsia. The neurovascular structures along the surgical corridor along with the nuances of the tentorium incision and splenium resection are discussed. The parietooccipital interhemispheric transtentorial approach provides a wide and safe corridor for surgical resection of pineal tumors.

Concomitant, Single Burr Hole Endoscopic Third Ventriculostomy and Tumor Biopsy for Pineal Lesions: Feasibility, Safety, and Benefits.

Obtaining a prompt diagnosis, avoiding indwelling ventriculoperitoneal shunt, and enhancing the predictive value of pathologic examinations are only some of the advantages conferred by a simultaneous third ventriculostomy and tumor biopsy in patients with pineal region tumors. The objective of this study was to retrospectively search the literature on concomitant, single burr hole endoscopic third ventriculostomy (ETV) and tumor biopsy (TB) for pineal region tumors and to analyze the feasibility, surgical safety, and benefits of these 2 combined procedures. Consequently, a comprehensive, systematic literature search was performed in compliance with the updated PRISMA 2020 guidelines within electronic databases MEDLINE/PubMed, EMBASE, PLOS, and Cochrane Library. Statistical analysis was performed with IBM SPSS 28.0.1.1(14), using Kendall's and Spearman's tests, with a P < 0.05 considered significant. A total of 25 studies were selected and included in this review, for a total of 368 patients (mean age 20.6 years; range 1-86 years; SD 17.5). More than two-thirds of the procedures were operated with a rigid endoscope and 27.6% were performed with either a flexible endoscope, a combination of the 2, or not otherwise specified. Germinoma represented the most frequent diagnosis (20.1%) followed by astrocytoma (12.9%) and pineocytoma (9.9%). The single-entry approach allowed a correct histologic diagnosis in 88.7% of the examined cases. Summing up, concomitant ETV and TB represent a valuable option for the management of non-communicating hydrocephalus and the initial assessment of pineal region tumors. The histologic confirmation rate was 88.7% in the examined cohort, with only 10% of the biopsies yielding inconclusive results.

The Minimally Invasive Lateral Occipital Infracortical Supra-/Transtentorial Approach in Surgery of Lesions of the Pineal Region: A Possible Alternative to the Standard Approaches.

OBJECTIVE: The pineal region is an anatomical region that is difficult to access surgically, especially when it comes to removing neoplasms. Four main surgical approaches to this region are used as standards nowadays: infratentorial supracerebellar, occipital supra-/transtentorial, interhemispheric, and transventricular approaches. All methods have both advantages and disadvantages and are associated to any extent with intra- and postoperative risks. We have developed a lateral minimally invasive occipital infracortical supra-/transtentorial (OICST) approach, which retains the advantages of the standard occipital transtentorial approach while improving tumor exposure and minimizing its disadvantages. METHODS: We describe 7 consecutive cases of successful complete removals of pineal tumor formations of various quality and size (3 pineal cysts, 2 pineocytomas, 1 meningioma, 1 medulloblastoma) using the OICST approach developed by us. Preoperative 3-dimensional and virtual reality-modeling and the use of a special retractor also contributed to reducing the size of the surgical approach. RESULTS: All patients underwent surgery for removal of a lesion in the pineal region and suffered from no new and permanent neurological deficits postoperatively. The mean size of the craniotomies was 2.3 × 1.85 cm. The minimally invasive approach developed by us carries the advantages of the standard occipital transtentorial approach, but minimizes its disadvantages. The main disadvantage of the standard occipital approach is excessive retraction of the occipital lobe, which is frequently associated with visual neurological deficits. Also, with occipital approach, the Rosenthal vein lying along the surgical corridor is frequently not good visible since the tumor is approached from its tip rather than side which limits the overview of the surgical field and can pose a risk. Damage to this vein can cause infarction of the basal ganglia. By approaching the pineal region from more laterally the size of the craniotomy can significantly be reduced, excessive retraction of the occipital lobe can be avoided and the risk of damage to large deep veins can be minimized. The cosmetic outcome with a small skin incision of only about 3 cm is also a very good side effect of this minimally invasive technique. CONCLUSIONS: The minimally invasive lateral OICST approach described by us can be successfully used in the surgery of pineal neoplasms. Reducing the size of the craniotomy does not limit the possibility of complete removal of tumors of various sizes and tissue consistency, and also minimizes the risks of both intra- and postoperative complications.

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.

Pineal Parenchymal Tumor of Intermediate Differentiation and DICER1 Syndrome: A Case Report.

DICER1 syndrome is a rare inherited tumor predisposition syndrome associated with an increased risk for several malignant and benign tumors. We present a patient with pineal parenchymal tumor of intermediate differentiation who was found to have a germline pathogenic variant in DICER1 gene. Pineoblastoma is a known DICER1-related tumor; however, the association between pineal parenchymal tumor of intermediate differentiation and DICER1 mutation is rare with only 1 recent large molecular study that has reported this association. This report adds to the evolving tumor spectrum of DICER1 and highlights the importance of molecular evaluation of pediatric brain tumors, for both therapeutic decisions and long-term surveillance.