Systemic tolerance of intravenous milrinone administration for cerebral vasospasm secondary to non-traumatic subarachnoid hemorrhage.

PURPOSE: Delayed cerebral ischemia (DCI) is a severe subarachnoid hemorrhage (SAH) complication, closely related to cerebral vasospasm (CVS). CVS treatment frequently comprises intravenous milrinone, an inotropic and vasodilatory drug. Our objective is to describe milrinone's hemodynamic, respiratory and renal effects when administrated as treatment for CVS. METHODS: Retrospective single-center observational study of patients receiving intravenous milrinone for CVS with systemic hemodynamics, oxygenation, renal disorders monitoring. We described these parameters' evolution before and after milrinone initiation (day - 1, baseline, day 1 and day 2), studied treatment cessation causes and assessed neurological outcome at 3-6 months. RESULTS: Ninety-one patients were included. Milrinone initiation led to cardiac output increase (4.5 L/min [3.4-5.2] at baseline vs 6.6 L/min [5.2-7.7] at day 2, p < 0.001), Mean Arterial Pressure decrease (101 mmHg [94-110] at baseline vs 95 mmHg [85-102] at day 2, p = 0.001) norepinephrine treatment requirement increase (32% of patients before milrinone start vs 58% at day 1, p = 0.002) and slight PaO2/FiO2 ratio deterioration (401 [333-406] at baseline vs 348 [307-357] at day 2, p = 0.016). Milrinone was interrupted in 8% of patients. 55% had a favorable outcome. CONCLUSION: Intravenous milrinone for CVS treatment seems associated with significant impact on systemic hemodynamics leading sometimes to treatment discontinuation.

Use of progestogens and the risk of intracranial meningioma: national case-control study.

OBJECTIVE: To assess the risk of intracranial meningioma associated with the use of selected progestogens. DESIGN: National case-control study. SETTING: French National Health Data System (ie, Système National des Données de Santé). PARTICIPANTS: Of 108 366 women overall, 18 061 women living in France who had intracranial surgery for meningioma between 1 January 2009 and 31 December 2018 (restricted inclusion periods for intrauterine systems) were deemed to be in the case group. Each case was matched to five controls for year of birth and area of residence (90 305 controls). MAIN OUTCOME MEASURES: Selected progestogens were used: progesterone, hydroxyprogesterone, dydrogesterone, medrogestone, medroxyprogesterone acetate, promegestone, dienogest, and intrauterine levonorgestrel. For each progestogen, use was defined by at least one dispensation within the year before the index date (within three years for 13.5 mg levonorgestrel intrauterine systems and five years for 52 mg). Conditional logistic regression was used to calculate odds ratio for each progestogen meningioma association. RESULTS: Mean age was 57.6 years (standard deviation 12.8). Analyses showed excess risk of meningioma with use of medrogestone (42 exposed cases/18 061 cases (0.2%) v 79 exposed controls/90 305 controls (0.1%), odds ratio 3.49 (95% confidence interval 2.38 to 5.10)), medroxyprogesterone acetate (injectable, 9/18 061 (0.05%) v 11/90 305 (0.01%), 5.55 (2.27 to 13.56)), and promegestone (83/18 061 (0.5%) v 225/90 305 (0.2 %), 2.39 (1.85 to 3.09)). This excess risk was driven by prolonged use (≥one year). Results showed no excess risk of intracranial meningioma for progesterone, dydrogesterone, or levonorgestrel intrauterine systems. No conclusions could be drawn concerning dienogest or hydroxyprogesterone because of the small number of individuals who received these drugs. A highly increased risk of meningioma was observed for cyproterone acetate (891/18 061 (4.9%) v 256/90 305 (0.3%), odds ratio 19.21 (95% confidence interval 16.61 to 22.22)), nomegestrol acetate (925/18 061 (5.1%) v 1121/90 305 (1.2%), 4.93 (4.50 to 5.41)), and chlormadinone acetate (628/18 061 (3.5%) v 946/90 305 (1.0%), 3.87 (3.48 to 4.30)), which were used as positive controls for use. CONCLUSIONS: Prolonged use of medrogestone, medroxyprogesterone acetate, and promegestone was found to increase the risk of intracranial meningioma. The increased risk associated with the use of injectable medroxyprogesterone acetate, a widely used contraceptive, and the safety of levonorgestrel intrauterine systems are important new findings.

Verbal fluency predicts work resumption after awake surgery in low-grade glioma patients.

BACKGROUND: Resuming professional activity after awake surgery for diffuse low-grade glioma (DLGG) is an important goal, which is not reached in every patient. Cognitive deficits can occur and persist after surgery. In this study, we analyzed the impact of mild cognitive impairments on the work resumption. METHODS: Fifty-four surgeries (including five redo surgeries) performed between 2012 and 2020 for grade 2 (45) and 3 (nine) DLGG in 49 professionally active patients (mean age 40 [range 23-58.) were included. We retrospectively extracted the results of semantic and phonemic verbal fluency tests from preoperative and 4-month postoperative cognitive assessments. Patients were interviewed about their working life after surgery, between April and June 2021. RESULTS: Patients (85%) returned to work, most within 3 to 6 months. Patients (76%) reported subjective complaints (primarily fatigue). Self-reported symptoms and individual and clinical variables had no impact on the work resumption. Late-postoperative average Z-scores in verbal fluency tasks were significantly lower than preoperative for the entire cohort (Wilcoxon test, p < 0.001 for semantic and p = 0.008 for phonemic fluency). The decrease in Z-scores was significantly greater (Mann Whitney U-test, semantic, p = 0.018; phonemic, p = 0.004) in the group of patients who did not return to work than in the group of patients who did. CONCLUSION: The proportion of patients returning to work was comparable to similar studies. A decrease in verbal fluency tasks could predict the inability to return to work.

Electrostimulation of the white matter of the posterior insula and medial operculum: perception of vibrations, heat, and pain.

ABSTRACT: This study aimed to characterize the sensory responses observed when electrically stimulating the white matter surrounding the posterior insula and medial operculum (PIMO). We reviewed patients operated on under awake conditions for a glioma located in the temporoparietal junction. Patients' perceptions were retrieved from operative reports. Stimulation points were registered in the Montreal Neurological Institute template. A total of 12 stimulation points in 8 patients were analyzed. Painful sensations in the contralateral leg were reported (5 sites in 5 patients) when stimulating the white matter close to the parcel OP2/3 of the Glasser atlas. Pain had diverse qualities: burning, tingling, crushing, or electric shock. More laterally, in the white matter of OP1, pain and heat sensations in the upper part of the body were described (5 sites in 2 patients). Intermingled with these sites, vibration sensations were also reported (3 sites in 2 patients). Based on the tractograms of 44 subjects from the Human Connectome Project data set, we built a template of the pathways linking the thalamus to OP2/3 and OP1. Pain sites were located in the thalamo-OP2/3 and thalamo-OP1 tracts. Heat sites were located in the thalamo-OP1 tract. In the 227 awake surgeries performed for a tumor located outside of the PIMO region, no patients ever reported pain or heat sensations when stimulating the white matter. Thus, we propose that the thalamo-PIMO connections constitute the main cortical inputs for nociception and thermoception and emphasize that preserving these fibers is of utmost importance to prevent the postoperative onset of a debilitating insulo-opercular pain syndrome.

A new subtype of diffuse midline glioma, H3 K27 and BRAF/FGFR1 co-altered: a clinico-radiological and histomolecular characterisation.

Diffuse midline gliomas (DMG) H3 K27-altered are incurable grade 4 gliomas and represent a major challenge in neuro-oncology. This tumour type is now classified in four subtypes by the 2021 edition of the WHO Classification of the Central Nervous System (CNS) tumours. However, the H3.3-K27M subgroup still appears clinically and molecularly heterogeneous. Recent publications reported that rare patients presenting a co-occurrence of H3.3K27M with BRAF or FGFR1 alterations tended to have a better prognosis. To better study the role of these co-driver alterations, we assembled a large paediatric and adult cohort of 29 tumours H3K27-altered with co-occurring activating mutation in BRAF or FGFR1 as well as 31 previous cases from the literature. We performed a comprehensive histological, radiological, genomic, transcriptomic and DNA methylation analysis. Interestingly, unsupervised t-distributed Stochastic Neighbour Embedding (tSNE) analysis of DNA methylation profiles regrouped BRAFV600E and all but one FGFR1MUT DMG in a unique methylation cluster, distinct from the other DMG subgroups and also from ganglioglioma (GG) or high-grade astrocytoma with piloid features (HGAP). This new DMG subtype harbours atypical radiological and histopathological profiles with calcification and/or a solid tumour component both for BRAFV600E and FGFR1MUT cases. The analyses of a H3.3-K27M BRAFV600E tumour at diagnosis and corresponding in vitro cellular model showed that mutation in H3-3A was the first event in the oncogenesis. Contrary to other DMG, these tumours occur more frequently in the thalamus (70% for BRAFV600E and 58% for FGFR1MUT) and patients have a longer overall survival with a median above three years. In conclusion, DMG, H3 K27 and BRAF/FGFR1 co-altered represent a new subtype of DMG with distinct genotype/phenotype characteristics, which deserve further attention with respect to trial interpretation and patient management.

Combined Transpetrosal Approach: 2-Dimensional Operative Video.

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE: This approach is suitable for petroclival lesions medial to V cranial nerve that extend in both middle and posterior fossa. It provides multiple surgical corridors with minimal brain retraction. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Several critical neurovascular structures of the petrous bone are at risk during the approach. Meticulous reading of the preoperative images is fundamental. It is mandatory to perform a thin section computed tomography scan, an MRI, and, in case of petroclival meningiomas, a digital subtraction angiography. ESSENTIAL STEPS OF THE PROCEDURE: In the first illustrative case, we present our current "mini-combined petrosectomy" with minimal drilling of the labyrinth. Positioning, skin incision, and craniotomy are illustrated in the video. Once all the important neurovascular structures are identified, we perform the anterior and the posterior petrosectomy, with preservation of the endolymphatic sac. We continue with dura mater opening and tentorium cutting. After tumor removal, we can appreciate an unique view of ipsilateral and contralateral cranial nerves, as well as pituitary stalk and major arteries. PITFALLS/AVOIDANCE OF COMPLICATIONS: To avoid injuries to the main neurovascular structures, neuronavigation, neuromonitoring, and Doppler can be useful. VARIANTS AND INDICATIONS FOR THEIR USE: The second illustrative case shows an extension of the combined petrosectomy to the anterior fossa, this made possible to perform a transsylvian approach for this giant sphenopetroclival meningioma. The patients consented to the procedure and to the publication of his/her images. Appropriate consent was obtained for the publication of the cadaveric images.

Endoscopic endonasal pituitary surgery: How we do it. Consensus statement on behalf of the EANS skull base section.

Introduction and research question: The use of an endoscope in skull base surgery provides a panoramic close-up view over the intracranial structures from multiple angles with excellent illumination, thus permitting greater extent of resection of tumors arising at sellar area, mostly represented by PitNet - Pituitary neuroendocrine tumors, with higher likelihood of preserving vital/intact gland tissue. For this refined specialty of neurosurgery, unique skills need to be acquired along a steep learning curve. Material and methods: EANS (European Association of Neurosurgical Societies) skull base section panelists were enrolled and 11 completed the survey: the goal was to provide a consensus statement of the endoscopic endonasal approach for pituitary adenoma surgery. Results: The survey consisted of 44 questions covering demographics data (i.e., academic/non-academic center, case load, years of experience), surgical techniques (i.e., use of neuronavigation, preoperative imaging), and follow-up management. Discussion and conclusions: In this paper we identified a series of tips and tricks at different phases of an endoscopic endonasal pituitary surgery procedure to underline the crucial steps to perform successful surgery and reduce complications: we took in consideration the principles of the surgical technique, the knowledge of the anatomy and its variations, and finally the importance of adjoining specialties experts.

Oncological and functional outcomes support early resection of incidental IDH-mutated glioma.

PURPOSE: The main objective was to assess the neuropsychological, epileptical, and oncological outcomes in a series of patients operated on for a IDH-mutated diffuse low-grade glioma (DLGG) of incidental discovery (iDLGG). METHODS: We retrospectively reviewed a consecutive series of surgically treated adults with DLGG and selected cases incidentally discovered. Tumor volumes, growth rates, and extents of resection (EOR) were assessed by volumetric measures of fluid-attenuated inversion recovery magnetic resonance imaging. The data on oncological, functional, and epileptical results were retrieved from the patients' digital files. RESULTS: Among all patients with DLGG resected at our center between June 2011 and April 2022, we found eleven cases with an incidental discovery. Resection was supratotal, gross total, and subtotal in 45.5%, 26.4%, and 18.1% of cases, respectively. The rate of epileptic seizures after the surgery was 9.1%. There were 45.4% of patients that had tumor progressions and the overall mean time to tumor progression was 42 months. After the surgery, 3 (27.3%) patients had mild neurocognitive deteriorations, which impeded the return to work in one patient (9.1%). There were no differences with previous series regarding clinical, radiological, and molecular characteristics. Similar results were also found for functional, surgical, epileptical, and oncological outcomes. CONCLUSION: Although the right approach for iDLGG is still a matter of debate, our data support the safety and effectiveness of early surgical resection. More studies are needed to firmly ground this early "preventive" surgery approach.

Oncological, cognitive, and employment outcomes in a series of patients with IDH-mutated glioma resected following neoadjuvant chemotherapy.

PURPOSE: Maximal safe tumor resection is the first line of treatment for IDH-mutated gliomas. However, when upfront surgical resection is deemed unsatisfactory due to tumor size and location, chemotherapy could represent an interesting alternative for reducing glioma extension and allowing for a safer and more efficient removal. METHODS: We performed a retrospective study (June 2011 to December 2021) on patients with IDH-mutated gliomas undergoing chemotherapy with a neoadjuvant intent, followed by surgical excision in awake conditions. MRI-imaging follow-up was conducted every 3-6 months. Neuropsychological assessments (NPSA) were performed for all patients before surgery, during post-operative period, and at later follow-up, and patients were periodically interviewed about their clinical and job status. RESULTS: We included 6 patients who underwent awake surgery after neoadjuvant chemotherapy (temozolomide in 5 cases, PCV in 1 case) for an IDH-mutated glioma (3 oligodendrogliomas and 3 astrocytomas). Median tumor volume reduction was 47%, allowing for complete resection in one patient, subtotal resection in 4 patients, and partial resection in 1 patient. No major adverse effects were observed under chemotherapy. At the 4 months NPSA, a worsening of flexibility was observed in 2 patients (verbal fluencies in one case and trail making test in the other). Three out of the four patients working full time before procedure resumed their job full time, after a 7 to 10 months delay. CONCLUSION: Neoadjuvant chemotherapy followed by maximal safe resection can be offered to patients affected by IDH-mutated gliomas for whom upfront surgery would be inadequate. More studies are necessary given the limited size of our sample.

Differences in intraoperative sampling during meningioma surgery regarding CNS invasion - Results of a survey on behalf of the EANS skull base section.

Introduction: and Research Question: Invasive growth of meningiomas into CNS tissue is rare but of prognostic significance. While it has entered the WHO classification as a stand-alone criterion for atypia, its true prognostic impact remains controversial. Retrospective analyses, on which the current evidence is based, show conflicting results. Discordant findings might be explained by different intraoperative sampling methodologies. Material and methods: To assess the applied sampling methods in the light of the novel prognostic impact of CNS invasion, an anonymous survey was designed and distributed via the EANS website and newsletter. The survey was open from June 5th until July 15th, 2022. Results: After exclusion of 13 incomplete responses, 142 (91.6%) datasets were used for statistical analysis. Only 47.2% of participants' institutions utilize a standardized sampling method, and 54.9% pursue a complete sampling of the area of contact between the meningioma surface and CNS tissue. Most respondents (77.5%) did not change their sampling practice after introduction of the new grading criteria to the WHO classification of 2016. Intraoperative suspicion of CNS invasion changes the sampling for half of the participants (49.3%). Additional sampling of suspicious areas of interest is reported in 53.5%. Dural attachment and adjacent bone are more readily sampled separately if tumor invasion is suspected (72.5% and 74.6%, respectively), compared to meningioma tissue with signs of CNS invasion (59.9%). Discussion and conclusions: Intraoperative sampling methods during meningioma resection vary among neurosurgical departments. There is need for a structured sampling to optimize the diagnostic yield of CNS invasion.

Transuncal Selective Amygdalohippocampectomy by an Inferolateral Preseptal Endoscopic Approach Through Inferior Eyelid Conjunctival Incision: An Anatomic Study.

BACKGROUND: Transorbital endoscopic approaches have been described for pathologies of anterior and middle fossae. Standard lateral orbitotomy gives access to mesial temporal lobe, but the axis of work is partially obscured by the temporal pole and working corridor is limited. OBJECTIVE: To evaluate the usefulness of an inferolateral orbitotomy to provide a more direct corridor to perform a transuncal selective amygdalohippocampectomy. METHODS: Three adult cadaveric specimens were used for a total of 6 dissections. A step-by-step description and illustration of the transuncal corridor for a selective amygdalohippocampectomy were performed using the inferolateral orbitotomy through an inferior eyelid conjunctival incision. The anatomic landmarks were demonstrated in detail. Orbitotomies and angles of work were measured from computed tomography scans, and the area of resection was illustrated by postdissection MRI. RESULTS: Inferior eyelid conjunctival incision was made for exposure of the inferior orbital rim. Inferolateral transorbital approach was performed to access the transuncal corridor. Endoscopic selective amygdalohippocampectomy was performed through the entorhinal cortex without damage to the temporal neocortex or Meyer's loop. The mean horizontal diameter of the osteotomy was 14.4 mm, and the vertical one was 13.6 mm. The mean angles of work were 65° and 35.5° in the axial and sagittal planes, respectively. Complete amygdalohippocampectomy was achieved in all 6 dissections. CONCLUSION: Transuncal selective amygdalohippocampectomy was feasible in cadaveric specimens using the inferolateral transorbital endoscopic approach avoiding damage to the temporal neocortex and Meyer's loop. The inferior eyelid conjunctival incision may result in an excellent cosmetic outcome.

The Anterolateral Approach, Revisited for Benign Jugular Foramen Tumors With Predominant Extracranial Extension: Microsurgical Anatomy and Case Series (SevEN-012).

BACKGROUND AND OBJECTIVES: The anterolateral approach (ALA) enables access to the mid and lower clivus, jugular foramen (JF), craniocervical junction, and cervical spine with added anterior and lateral exposure than the extreme lateral and endoscopic endonasal approach, respectively. We describe the microsurgical anatomy of ALA with cadaveric specimens and report our clinical experience for benign JF tumors with predominant extracranial extension. METHODS: A stepwise and detailed microsurgical neurovascular anatomy of ALA was explored with cadaveric specimens. Then, the clinical results of 7 consecutive patients who underwent ALA for benign JF tumors with predominant extracranial extension were analyzed. RESULTS: A hockey stick skin incision is made along the superior nuchal line to the anterior edge of the sternocleidomastoid muscle (SCM). ALA involves layer-by-layer muscle dissection of SCM, splenius capitis, digastric, longissimus capitis, and superior oblique muscles. The accessory nerve runs beneath SCM and is found at the posterior edge of the digastric muscle. The internal jugular vein (IJV) is lateral to and at the level of the accessory nerve. The occipital artery passes over the longissimus capitis muscle and IJV and into the external carotid artery, which is lateral and superficial to IJV. The internal carotid artery (ICA) is more medial and deeper than external carotid artery and is in the carotid sheath with the vagus nerve and IJV. The hypoglossal and vagus nerves run along the lateral and medial side of ICA, respectively. Prehigh cervical carotid, prejugular, and retrojugular surgical corridors allow deep and extracranial access around JF. In the case series, gross and near-total resections were achieved in 6 (85.7%) patients without newly developed cranial nerve deficits. CONCLUSION: ALA is a traditional and invaluable neurosurgical approach for benign JF tumors with predominant extracranial extension. The anatomic knowledge of ALA increases competency in adding anterior and lateral exposure of extracranial JF.

Tailored frontotemporoorbitozygomatic (FTOZ) craniotomy for a large anterior clinoidal meningioma.

Large anterior clinoidal meningiomas are tumors that arise on the anterior clinoid often compressing and encasing the nearby neurovascular structures such as the carotid artery and the optic nerve. These remain as very challenging cases for neurosurgeons because of the issues concerning preservation of critical structures and gross total excision. In this video submission, we will show a case of a large anterior clinoidal meningioma through a tailored frontotemporoorbitozygomotic craniotomy with emphasis on anterior clinoidectomy and the different corridors that can be obtained by this particular approach. The methodical dissection of the tumor and the other critical structures can also be seen.

The mutational landscape of skull base and spinal chordomas and the identification of potential prognostic and theranostic biomarkers.

OBJECTIVE: Chordomas are rare bone neoplasms characterized by a high recurrence rate and no benefit from any approved medical treatment to date. However, the investigation of molecular alterations in chordomas could be essential to prognosticate, guide clinical decision-making, and identify theranostic biomarkers. The aim of this study was to provide a detailed genomic landscape of a homogeneous series of 64 chordoma samples, revealing driver events, theranostic markers, and outcome-related genomic features. METHODS: The authors conducted whole-exome sequencing (WES), targeted next-generation sequencing, and RNA sequencing of 64 skull base and spinal chordoma samples collected between December 2006 and September 2020. Clinical, histological, and radiological data were retrospectively analyzed and correlated to genetic findings. RESULTS: The authors identified homozygous deletions of CDKN2A/2B, PIK3CA mutations, and alterations affecting genes of SWI/SNF chromatin remodeling complexes (PBRM1 and ARID1A) as potential theranostic biomarkers. Using matched germline WES, they observed a higher frequency of a common genetic variant (rs2305089; p.(Gly177Asp)) in TBXT (97.8%, p < 0.001) compared to its distribution in the general population. PIK3CA mutation was identified as an independent biomarker of short progression-free survival (HR 10.68, p = 0.0008). Loss of CDKN2A/2B was more frequently observed in spinal tumors and recurrent tumors. CONCLUSIONS: In the current study, the authors identified driver events such as PBRM1 and PIK3CA mutations, TBXT alterations, or homozygous deletions of CDKN2A/2B, which could, for some, be considered potential theranostic markers and could allow for identifying novel therapeutic approaches. With the aim of a future biomolecular prognostication classification, alterations affecting PIK3CA and CDKN2A/2B could be considered as poor prognostic biomarkers.

Endoscope-assisted anterolateral approach for a craniovertebral junction chordoma.

Chordomas of craniovertebral junction represent a challenging pathology for neurosurgeons, due to their deep location, proximity with critical neurovascular structures and local aggressiveness. Several surgical options are available for these tumors: both endoscopic extended approaches and open approaches. We present the case of a 24 years old female with a craniovertebral junction chordoma with anterior and right lateral extension. For this case, an anterolateral approach with endoscopic assistance was chosen. Key surgical steps are presented. In the postoperative course the neurological symptoms improved and there were no complications. Unfortunately, she had an early recurrence of tumor two months later, prior the beginning of radiotherapy. After multidisciplinary consultation, we performed a second surgical removal and a posterior cervical spine arthrodesis. The anterolateral approach is a valuable option for craniovertebral junction chordomas with lateral extension and the endoscope assistance allowed to reach the narrowest and furthermost points. The patients must be referred to multidisciplinary skull base surgery centers and be addressed to early adjuvant radiation therapy.

Opposed evolution of the osseous and soft parts of progestin-associated osteomeningioma after progestin intake discontinuation.

OBJECTIVE: Numerous studies have confirmed a strong association between progestins and meningiomas and the regression and/or stabilization of meningiomas after discontinuation of treatment. Osteomeningiomas represent a small subgroup of meningiomas that appear to be more common among progestin-related meningiomas. However, the specificity of the behavior of this subset of meningiomas after discontinuation of progestin has not yet been assessed. METHODS: Thirty-six patients (mean age 49.5 years) who presented with at least one progestin-related osteomeningioma (48 tumors total) were identified from a prospectively collected database of patients and had been referred to our department for meningioma and had documented use of cyproterone acetate, nomegestrol acetate, and/or chlormadinone acetate. Hormonal treatment was stopped at the time of diagnosis for all the patients, and the clinical and radiological evolution of this subgroup of tumors was evaluated. RESULTS: For half of the 36 patients, treatment was prescribed for signs of hyperandrogenism, such as hirsutism, alopecia, or acne. Most lesions were spheno-orbital (35.4%) or frontal (31.2%). Although the tissular part of the meningioma shrank in 77.1% of cases, the osseous part exhibited discordant behavior with 81.3% showing volume progression. The combination of estrogens, as well as the prolonged duration of progestin treatment, seems to increase the risk of progression of the osseous part after treatment discontinuation (p = 0.02 and p = 0.028, respectively). No patient required surgical treatment at diagnosis or during the study. CONCLUSIONS: These results show that while the soft intracranial part of progestin-related osteomeningioma tumor is the most likely to regress after treatment discontinuation, the bony part is more likely to increase in volume. These findings suggest the need for careful follow-up of these patients, especially those with tumors near the optical apparatus.