Prolactinoma extension as a contributing factor in dopamine agonist-induced CSF rhinorrhea: a systematic review of the literature.

BACKGROUND: Dopamine agonist-induced cerebrospinal fluid (CSF) rhinorrhea is an uncommon treatment-related complication arising in 6.1% of prolactinoma patients treated with dopamine agonists. Locally invasive prolactinomas may create CSF fistulae through formation of dural and osseous skull base defects. Tumor shrinkage secondary to dopamine agonist therapy unmasks skull base defects, thus inducing CSF rhinorrhea. In these cases, repair of the leak may be achieved through collaborative surgical intervention by rhinologists and neurosurgeons. Multiple variables have been investigated as potential contributors to the risk of CSF rhinorrhea development in medically treated prolactinoma patients, with little consensus. OBJECTIVE: The primary aim of our study was the characterization of risk factors for CSF rhinorrhea development following dopamine agonist treatment. METHODS: A systematic review of the literature was conducted to identify cases of CSF rhinorrhea following dopamine agonist treatment of prolactinoma. The clinical history, radiographic findings and treatment outcomes are discussed. RESULTS: Fifty-four patients with dopamine agonist-induced CSF rhinorrhea were identified across 23 articles published from 1979 to 2019. Description of diagnostic imaging [computed tomography (CT)/magnetic resonance imaging (MRI)] was not provided for 18/54 subjects. For the 36 cases that described prolactinoma appearance on CT or MRI, invasion of the cavernous sinuses was reported in 13 (36.1%) and invasion of the sphenoid sinus was reported in 18 (50%). CONCLUSION: Based on our systematic review, we propose that CT findings of osseous erosion of the sella or the anterior skull base may predict dopamine agonist-induced CSF rhinorrhea. We recommend obtaining a thin-slice CT of the sinuses in cases with MRI evidence of sphenoid involvement.

High-Grade Biphenotypic Sinonasal Sarcoma: A Case Report.

Introduction Biphenotypic sinonasal sarcoma (BSNS) is a recently found entity that first described by Lewis et al. It was then added to the 4th edition of the World Health Organization (WHO) of head and neck tumors in 2012. BSNS has been described as a rare low-grade sarcoma arising in the upper sinonasal tract. It is believed that in the past, BSNS was, likely, previously diagnosed as other low-grade or benign malignancies. Fibrosarcoma, leiomyosarcoma, and peripheral nerve sheath tumors, all fall within the differential diagnosis of BSNS. However, BSNS is unlike other mesenchymal sinonasal tumors, as it displays both neural and myogenic differentiation. BSNS has thus far been recognized in only a hand full of case reports, all of which have reported similar morphologic features of a low-grade soft tissue tumor with neural involvement arising from the nasal cavity or ethmoid air cells in middle aged individuals. In fact, being low-grade sarcoma became such a hallmark characteristic of this tumor that it even received the name low-grade sinonasal sarcoma with neural and myogenic features or LGSSNMF. Case Presentation We present, however, for the first time, a high-grade differentiation of BSNS in an otherwise healthy 72-year-old female. The patient was referred from an outside ENT (ear, nose, and throat) after pathology from a presumed polypectomy returned positive for a BSNS. Initial imaging revealed erosion through the bilateral lamina papyracea, anterior cranial fossa floor, and posterior table of the frontal sinus. She then underwent a combined endoscopic and bicoronal open approach for resection of the skull base lesion that was found to encompass the entirety of the sinonasal cavities bilaterally. Postoperatively, the patient underwent significant complications including infection of the pericranial flap, pneumocephalus, and eventually death. Discussion As BSNS is a fairly new entity, currently there has only been four case series conducted, each identifying features of a low-grade sarcoma with both myogenic and neural differentiation. Histologically, BSNS has monophasic spindle cells with uniform, elongated nuclei with scant cytoplasm between benign proliferations of surface-type respiratory epithelium, with a low mitotic rate. Our case, however, revealed pleomorphic hyperchromatic cells with high mitotic activity and necrosis with invasion of bone, staging it as high grade. Immunohistochemistry also differed from the previously reported standards. This case describes a new category for BSNS which may change the differential diagnosis, management, and surgical recommendations that are currently utilized for this skull base neoplasm.

Primary Dural Repair Using Titanium Microclips Following Lateral Skull Base Surgery.

Objective Standard techniques for primary dural repair following lateral skull base surgery are both technically challenging and time consuming without the potential for primary dural repair. Inadequate closure may result in postoperative cerebrospinal fluid (CSF) leak infectious sequalae. Traditional methods of dural repair rely on secondary obliteration of the CSF fistula. We hypothesized that the use of nonpenetrating titanium microclips may serve as a useful adjunct in primary dural repair or the establishment of an immobile repair layer following lateral skull base surgery. Methods Here, we report a novel technique for primary dural repair using nonpenetrating titanium microclips as an adjunct to standard techniques in a series of six patients with lateral skull base pathologies. Results A total of six consecutive lateral skull base tumor patients with titanium microclip dural reconstruction were included in our case series. Lateral skull base pathologies represented in this group included two jugular foramen schwannomas, one vestibular schwannoma, one petroclival meningioma, one glomus jugulare paraganglioma, and one jugular foramen chordoid meningioma. Conclusion To our knowledge, this is the first report on the use of microclips in repairing dural defects following lateral skull base surgery. Surgical outcomes for this small case series suggest that dural repair of the later skull base with nonpenetrating titanium microclips is a useful adjunct in dural repair following lateral skull base surgery.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of neuropathology in the management of progressive glioblastoma in adults.

TARGET POPULATION: These recommendations apply to adult patients with progressive or recurrent glioblastoma (GBM). QUESTION: For adult patients with progressive glioblastoma does testing for Isocitrate Dehydrogenase (IDH) 1 or 2 mutations provide new additional management or prognostic information beyond that derived from the tumor at initial presentation? RECOMMENDATION: Level III: Repeat IDH mutation testing is not necessary if the tumor is histologically similar to the primary tumor and the patient's clinical course is as expected. QUESTION: For adult patients with progressive glioblastoma does repeat testing for MGMT promoter methylation provide new or additional management or prognostic information beyond that derived from the tumor at initial presentation and what methods of detection are optimal? RECOMMENDATION: Level III: Repeat MGMT promoter methylation is not recommended. QUESTION: For adult patients with progressive glioblastoma does EGFR amplification or mutation testing provide management or prognostic information beyond that provided by histologic analysis and if performed on previous tissue samples, does it need to be repeated? RECOMMENDATION: Level III: In cases that are difficult to classify as glioblastoma on histologic features EGFR amplification testing may help in classification. If a previous EGFR amplification was detected, repeat testing is not necessary. Repeat EGFR amplification or mutational testing may be recommended in patients in which target therapy is being considered. QUESTION: For adult patients with progressive glioblastoma does large panel or whole genome sequencing provide management or prognostic information beyond that derived from histologic analysis? RECOMMENDATION: Level III: Primary or repeat large panel or whole genome sequencing may be considered in patients who are eligible or interested in molecularly guided therapy or clinical trials. QUESTION: For adult patients with progressive glioblastoma should immune checkpoint biomarker testing be performed to provide management and prognostic information beyond that obtained from histologic analysis? RECOMMENDATION: Level III: The current evidence does not support making PD-L1 or mismatch repair (MMR) enzyme activity a component of standard testing. QUESTION: For adult patients with progressive glioblastoma are there meaningful biomarkers for bevacizumab responsiveness and does their assessment provide additional information for tumor management and prognosis beyond that learned by standard histologic analysis? RECOMMENDATION: Level III: No established Bevacizumab biomarkers are currently available based upon the inclusion criteria of this guideline.

Practice Patterns of Ventriculoperitoneal Shunt Placement in Academic and Community Settings: A National Survey of Practicing Neurosurgeons.

OBJECTIVE: We sought to assess the practice patterns of ventriculoperitoneal shunt (VPS) placement by neurosurgeons at academic, community, and government-based institutions. METHODS: Using the American Association of Neurological Surgeons directory, a total of 3673 practicing neurosurgeons were contacted. The survey received 495 responses (57% academic, 41% community, 3% other/government based). The survey consisted of 9 questions to assess the frequency of general surgery assistance for distal VPS placement and the use of cranial neuronavigation for proximal placement and to assess subjective beliefs of personal practice pattern and the influence on shunt failure rates. RESULTS: Almost half of the respondents reported using general surgery less than half of the time for distal VPS placement. Regardless of personal practice patterns, roughly one third of respondents reported that general surgery assistance is a common or somewhat common practice at their institution. The most common reasons for recruiting general surgery assistance were cases of higher complexity. Although commonly used, almost 40% of respondents believe that general surgery assistance does not decrease shunt failure rates. Cranial neuronavigation is used less than half of the time, and the most common reason was for improved accuracy. Almost half of the respondents believe navigation does decrease shunt failure rates. CONCLUSIONS: General surgery assistance for distal placement and neuronavigation for the proximal placement of VPS catheters are both commonly used by neurosurgeons in academic, community, and other practice locations. This survey provides the first assessment of practice patterns nationally. The results demonstrate that roughly half of the practicing neurosurgeons use general surgery assistance and neuronavigation, particularly for complex or high-risk cases.

Nonfunctioning Pituitary Lesions.

Nonfunctioning pituitary lesions represent a subset of pituitary adenomas that do not manifest with clinical features of hormone hypersecretion. Because of their indolent nature, their diagnosis is elusive, often resulting in presentation after the tumors have grown large enough to cause compressive symptoms. Although they are clinically silent, the various subtypes correspond to the predominant cell line of origin and therefore are biochemically distinct from one another. This article reviews the biochemical, clinical, and histopathologic features of each of these subtypes. A rubric is provided for diagnostic work-up of these lesions and the management options available to the treating clinician.

Primary Repair of Posteriorly Located Anterior Skull Base Dural Defects Using Nonpenetrating Titanium Clips in Cranial Trauma.

Objective Primary repair of posteriorly located anterior skull base (ASB) dural defects following cranial trauma is made difficult by narrow operative corridors and adherent dura mater. Inadequate closure may result in continued cerebrospinal fluid (CSF) leak and infectious sequelae. Here, we report surgical outcomes following the use of nonpenetrating titanium microclips as an adjunctive repair technique in traumatic anterior skull base dural defects extending from the olfactory groove to the tuberculum sellae. Methods All trauma patients who underwent a bifrontal craniotomy from January 2013 to October 2019 were retrospectively reviewed. Patients with ASB defects located at posterior to the olfactory groove were analyzed. Patients with isolated frontal sinus fractures were excluded. All patients presented with CSF leak or radiographic signs of dural compromise. Patients were divided according to posterior extent of injury. Patient characteristics, imaging, surgical technique, and outcomes are reported. Results A total of 19 patients who underwent a bifrontal craniotomy for repair of posteriorly located ASB dural defects using nonpenetrating titanium microclips were included. Defects were divided by location: olfactory groove (10/19), planum sphenoidale (6/19), and tuberculum sellae (3/19). No patients demonstrated a postoperative CSF leak. No complications related to the microclip technique was observed. Clip artifact did not compromise postoperative imaging interpretation. Conclusion Primary repair of posteriorly located ASB dural defects is challenging due to narrow working angles and thin dura mater. Use of nonpenetrating titanium microclips for primary repair of posteriorly located dural defects is a reasonable adjunctive repair technique and was associated with no postoperative CSF leaks in this cohort.

A systematic review of amino acid PET in assessing treatment response to temozolomide in glioma.

The response assessment in neuro-oncology (RANO) criteria have been the gold standard for monitoring treatment response in glioblastoma (GBM) and differentiating tumor progression from pseudoprogression. While the RANO criteria have played a key role in detecting early tumor progression, their ability to identify pseudoprogression is limited by post-treatment damage to the blood-brain barrier (BBB), which often leads to contrast enhancement on MRI and correlates poorly to tumor status. Amino acid positron emission tomography (AA PET) is a rapidly growing imaging modality in neuro-oncology. While contrast-enhanced MRI relies on leaky vascularity or a compromised BBB for delivery of contrast agents, amino acid tracers can cross the BBB, making AA PET particularly well-suited for monitoring treatment response and diagnosing pseudoprogression. The authors performed a systematic review of PubMed, MEDLINE, and Embase through December 2021 with the search terms "temozolomide" OR "Temodar," "glioma" OR "glioblastoma," "PET," and "amino acid." There were 19 studies meeting inclusion criteria. Thirteen studies utilized [18F]FET, five utilized [11C]MET, and one utilized both. All studies used static AA PET parameters to evaluate TMZ treatment in glioma patients, with nine using dynamic tracer parameters in addition. Throughout these studies, AA PET demonstrated utility in TMZ treatment monitoring and predicting patient survival.

Congress of Neurological Surgeons systematic review and evidence-based guidelines update on the role of imaging in the management of progressive glioblastoma in adults.

TARGET POPULATION: These recommendations apply to adults with glioblastoma who have been previously treated with first-line radiation or chemoradiotherapy and who are suspected of experiencing tumor progression. QUESTION: In patients with previously treated glioblastoma, is standard contrast-enhanced magnetic resonance imaging including diffusion weighted imaging useful for diagnosing tumor progression and differentiating progression from treatment-related changes? LEVEL II: Magnetic resonance imaging with and without gadolinium enhancement including diffusion weighted imaging is recommended as the imaging surveillance method to detect the progression of previously diagnosed glioblastoma. QUESTION: In patients with previously treated glioblastoma, does magnetic resonance spectroscopy add useful information for diagnosing tumor progression and differentiating progression from treatment-related changes beyond that derived from standard magnetic resonance imaging with and without gadolinium enhancement? LEVEL II: Magnetic resonance spectroscopy is recommended as a diagnostic method to differentiate true tumor progression from treatment-related imaging changes or pseudo-progression in patients with suspected progressive glioblastoma. QUESTION: In patients with previously treated glioblastoma, does magnetic resonance perfusion add useful information for diagnosing tumor progression and differentiating progression from treatment-related changes beyond that derived from standard magnetic resonance imaging with and without gadolinium enhancement? LEVEL III: Magnetic resonance perfusion is suggested as a diagnostic method to differentiate true tumor progression from treatment-related imaging changes or pseudo-progression in patients with suspected progressive glioblastoma. QUESTION: In patients with previously treated glioblastoma, does the addition of single-photon emission computed tomography (SPECT) provide additional useful information for diagnosing tumor progression and differentiating progression from treatment-related changes beyond that derived from standard magnetic resonance imaging with and without gadolinium enhancement? LEVEL III: Single-photon emission computed tomography imaging is suggested as a diagnostic method to differentiate true tumor progression from treatment-related imaging changes or pseudo-progression in patients with suspected progressive glioblastoma. QUESTION: In patients with previously treated glioblastoma, does 18F-fluorodeoxyglucose positron emission tomography add useful information for diagnosing tumor progression and differentiating progression from treatment-related changes beyond that derived from standard magnetic resonance imaging with and without gadolinium enhancement? LEVEL III: The routine use of 18F-fluorodeoxyglucose positron emission tomography to identify progression of glioblastoma is not recommended. QUESTION: In patients with previously treated glioblastoma, does positron emission tomography with amino acid agents add useful information for diagnosing tumor progression and differentiating progression from treatment-related changes beyond that derived from standard magnetic resonance imaging with and without gadolinium enhancement? LEVEL III: It is suggested that amino acid positron emission tomography be considered to assist in the differentiation of progressive glioblastoma from treatment related changes.

Resection and radiotherapy for intracranial ependymoma: a multiinstitutional 50-year experience.

OBJECTIVE: Maximal safe resection is the standard-of-care treatment for adults with intracranial ependymoma. The value of adjuvant radiotherapy remains unclear as these tumors are rare and current data are limited to a few retrospective cohort studies. In this study, the authors assembled a cohort of patients across multiple international institutions to assess the utility of adjuvant radiotherapy in this patient population. METHODS: Adults with intracranial ependymoma managed surgically at the University Health Network in Toronto, Canada, the University of Oklahoma Health Sciences Center in Oklahoma City, Oklahoma, and The Ottawa Hospital in Ottawa, Canada, were included in this study. The primary end points were progression-free survival (PFS) and overall survival (OS). Clinicopathological variables were assessed in univariate and multivariate Cox proportional hazard models for prognostic significance of PFS and OS. RESULTS: A total of 122 patients diagnosed between 1968 and 2019 were identified for inclusion. The majority of patients had grade II ependymomas on histopathology (78%) that were infratentorially located (71%), underwent gross-total (GTR) or near-total resection (NTR; 55%), and were treated with adjuvant radiotherapy (67%). A volumetric analysis of the extent of resection in 49 patients with available tumor volume data supported the accuracy of the categorical GTR, NTR, and subtotal resection (STR) groups utilized. Independent statistically significant predictors of poorer PFS in the multivariate analysis included STR or biopsy (vs GTR/NTR; HR 5.4, 95% confidence interval [CI] 2.4-11.0, p < 0.0001) and not receiving adjuvant radiotherapy; cranial (HR 0.5, 95% CI 0.2-1.1) and craniospinal (HR 0.2, 95% CI 0.04-0.5) adjuvant radiotherapy regimens improved PFS (p = 0.0147). Predictors of poorer OS in the multivariate analysis were grade III histopathology (vs grade II: HR 5.7, 95% CI 1.6-20.2, p = 0.0064) and undergoing a biopsy/STR (vs GTR/NTR: HR 9.8, 95% CI 3.2-30.1, p = 0.0001). CONCLUSIONS: The results of this 50-year experience in treating adult intracranial ependymomas confirm an important role for maximal safe resection (ideally GTR or NTR) and demonstrate that adjuvant radiotherapy improves PFS. This work will guide future studies as testing for molecular ependymoma alterations become incorporated into routine clinical practice.

A systematic review of the utility of amino acid PET in assessing treatment response to bevacizumab in recurrent high-grade glioma.

BACKGROUND: Currently, bevacizumab (BEV), an antiangiogenic agent, is used as an adjunctive therapy to re-irradiation and surgery in patients with recurrent high-grade gliomas (rHGG). BEV has shown to decrease enhancement on MRI, but it is often unclear if these changes are due to tumor response to BEV or treatment-induced changes in the blood brain barrier. Preliminary studies show that amino acid PET can aid in distinguishing these changes on MRI. METHODS: The authors performed a systematic review of PubMed and Embase through July 2020 with the search terms 'bevacizumab' or 'Avastin' and 'recurrent glioma' and 'PET,' yielding 38 papers, with 14 meeting inclusion criteria. RESULTS: Thirteen out of fourteen studies included in this review used static PET and three studies used dynamic PET to evaluate the use of BEV in rHGG. Six studies used the amino acid tracer [18F]FET, four studies used [11C]MET, and four studies used [18F]FDOPA. CONCLUSION: [18F]FET, [11C]MET, and [18F]FDOPA PET in combination with MRI have shown promising results for improving accuracy in diagnosing tumor recurrence, detecting early treatment failure, and distinguishing between tumor progression and treatment-induced changes in patients with rHGG treated with BEV.

Dynamic Occlusion of Distal Ventriculoperitoneal Shunt Catheter after Infusion Port Placement: A New Shunt Malfunction.

Shunt failure requiring reintervention remains a common complication of hydrocephalus treatment. Here, we report a novel cause of mechanical shunt obstruction in an adult patient: position-dependent intermittent occlusion via an infusion port catheter. A 51-year-old woman with a grade II oligodendroglioma presented in a delayed fashion following surgery with a pseudomeningocele. She underwent ventriculoperitoneal shunt placement due to communicating hydrocephalus, resolving her pseudomeningocele. Shortly thereafter, she underwent placement of a subclavian infusion port at an outside institution. Her pseudomeningocele returned. Imaging demonstrated close proximity of her port catheter to the shunt catheter overlying the clavicle. Her shunt was tapped demonstrating a patent ventricular catheter with normal pressure. She underwent shunt exploration after her pseudomeningocele did not respond to valve adjustment. Intraoperative manometry demonstrated head position-dependent distal catheter obstruction. Repeat manometry following distal catheter revision demonstrated normal runoff independent of position. Her pseudomeningocele was resolved on follow-up. To our knowledge, this is the only reported case of intermittent, position-dependent distal catheter obstruction. Shunted patients with concern for malfunction following subclavian infusion port placement should be evaluated for possible dynamic obstruction of their distal catheter when the two catheters are in close proximity along the clavicle.

Aggressive Progression of a WHO Grade I Meningioma of the Posterior Clinoid Process: An Illustration of the Risks Associated With Observation of Skull Base Meningiomas.

Benign, small, and asymptomatic World Health Organization grade I meningiomas are usually managed expectantly with surveillance imaging with the assumption that they are predictably slowing growing. In this paper, we report the case of an incidentally discovered small, right-sided posterior clinoid meningioma in a 53-year-old female. The tumor was managed conservatively but an annual surveillance magnetic resonance imaging demonstrated that the meningioma had an unexpected significant growth impinging on the brainstem, requiring surgical resection and radiosurgery for residual tumor. Despite histopathological confirmation of a grade I meningioma, the tumor recurred significantly and incurred substantial neurological deficits, requiring further surgery and radiotherapy. This report illustrates the potential pitfall for expectant management of small meningiomas in anatomically precarious locations and draws attention to the need for detailed informed discussions with patients regarding the management of these tumors.

Rosette-forming glioneuronal tumor: an illustrative case and a systematic review.

BACKGROUND: Rosette-forming glioneuronal tumors (RGNTs) are rare, low-grade, primary CNS tumors first described in 2002 by Komori et al. RGNTs were initially characterized as a World Health Organization (WHO) grade I tumors typically localized to the fourth ventricle. Although commonly associated with an indolent course, RGNTs have the potential for aggressive behavior. METHODS: A comprehensive search of PubMed and Web of Science was performed through November 2019 using the search term "rosette-forming glioneuronal tumor." Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. English, full-text case reports and series with histopathological confirmation were included. Patient demographics, presentations, MRI features, tumor location, treatment, and follow-up of all 130 cases were extracted. RESULTS: A 19-year-old man with a history of epilepsy and autism presented with acute hydrocephalus. MRI scans from 2013 to 2016 demonstrated unchanged abnormal areas of cortex in the left temporal lobe with extension into the deep gray-white matter. On presentation to our clinic in 2019, the lesion demonstrated significant progression. The patient's tumor was identified as RGNT, WHO grade I. One hundred thirty patients were identified across 80 studies. CONCLUSION: RGNT has potential to transform from an indolent tumor to a tumor with more aggressive behavior. The results of our systematic review provide insight into the natural history and treatment outcomes of these rare tumors.

Laser Interstitial Thermal Therapy Case Series: Choosing the Correct Number of Fibers Depending on Lesion Size.

BACKGROUND: Laser interstitial thermal therapy (LITT) is being used for the treatment of recurrent glioblastoma multiforme (GBM). Lesions can be treated using 1 or multiple LITT fibers depending on the preference of surgeons. Usually, more fibers are needed for coverage of larger tumors. OBJECTIVE: To investigate and analyze how tumor size affected the number of LITT fibers used. METHODS: This is a retrospective review of patients undergoing treatment of recurrent GBM. Patients were treated with up to 4 LITT fibers for adequate tumor coverage. Patient demographics, tumor characteristics, length of stay, complications, and biopsy results were recorded. RESULTS: A total of 43 cases were treated using LITT, and of these cases, 31 consisted of contiguous lesions. We used more fibers to treat larger tumor volumes. On average, for each 5 cc of tumor volume, a fiber was added for proper coverage (P = .554). Complications and length of stay were similar across the groups (P = .378, P = .941). CONCLUSION: LITT can be used for the treatment of recurrent GBM. For each 5 cc of tumor volume, a LITT fiber can be added to the treatment plan.

Natural history of intracranial meningiomas.

We know that the extent of resection is the greatest predictor of long-term survival. However, the potential tradeoff for gross total resection in difficult locations is diminished quality of life. Benign subtotally resected or small incidentally discovered meningiomas may be followed clinically especially in the elderly. In addition, radiosurgery plays a role in the treatment of meningiomas as a primary treatment modality, or as a salvage therapy. Decisions regarding management should be made with an understanding of the natural history and rate of growth. In this chapter we review the known meningioma epidemiology as well as the growth patterns of meningiomas based upon location.

Laser Interstitial Thermal Therapy for Metastatic Melanoma After Failed Radiation Therapy: A Case Series.

BACKGROUND: Laser interstitial thermal therapy (LITT) is a growing technology to treat a variety of brain lesions. It offers an alternative to treatment options, such as open craniotomy and stereotactic radiosurgery. OBJECTIVE: To analyze our experience using LITT for metastatic melanoma. METHODS: This is a retrospective chart review of the patients from our institution. Our case series involves 5 patients who had previously failed radiation treatment. RESULTS: Our patients have low complication rates and short hospital stays. Both are considerably lower when compared to the literature for metastatic melanoma. CONCLUSION: LITT is a safe therapy, with few complications and short hospital stays.

Myxoid glioneuronal tumor, PDGFRA p.K385-mutant: clinical, radiologic, and histopathologic features.

"Myxoid glioneuronal tumor, PDGFRA p.K385-mutant" is a recently described tumor entity of the central nervous system with a predilection for origin in the septum pellucidum and a defining dinucleotide mutation at codon 385 of the PDGFRA oncogene replacing lysine with either leucine or isoleucine (p.K385L/I). Clinical outcomes and optimal treatment for this new tumor entity have yet to be defined. Here, we report a comprehensive clinical, radiologic, and histopathologic assessment of eight cases. In addition to its stereotypic location in the septum pellucidum, we identify that this tumor can also occur in the corpus callosum and periventricular white matter of the lateral ventricle. Tumors centered in the septum pellucidum uniformly were associated with obstructive hydrocephalus, whereas tumors centered in the corpus callosum and periventricular white matter did not demonstrate hydrocephalus. While multiple patients were found to have ventricular dissemination or local recurrence/progression, all patients in this series remain alive at last clinical follow-up despite only biopsy or subtotal resection without adjuvant therapy in most cases. Our study further supports "myxoid glioneuronal tumor, PDGFRA p.K385-mutant" as a distinct CNS tumor entity and expands the spectrum of clinicopathologic and radiologic features of this neoplasm.