Extended sphenoidotomy combined with transpterygoid approach for sphenoidal sinus inverted papilloma.

PURPOSE: Inverted papilloma of the sphenoid sinus (IPSS) is a rare tumor with debated surgical management due to its proximity to vital structures. The aim of this manuscript is to highlight the role of a transpterygoid approach (TPA) and pedicle-orientated strategy in case of involvement of critical structures in IPSS and compare it with data from the literature. METHODS: Patients with primary IPSS between January 2000 and June 2021 were included. Pre-operative CT/MRI were analyzed to classify the pneumatization of the SS and predict the insertion point of the inverted papilloma. All patients were treated with a trans-sphenoidal approach which was combined with a TPA in case of lateral insertion point. A systematic search was also performed to summarize the available literature. RESULTS: Twenty-two patients were treated for IPSS. By CT, the SS was categorized with type III pneumatization in 72.8% of cases. Eleven patients (50%) were treated with a TPA with a statistical association with the insertion point on the SS lateral wall (p = 0.01), rather than a SS pneumatization (p = 0.63). The overall success was 95.5% after a mean follow-up of 35.9 months. For the literature, 26 publications were included on 97 patients and described a trans-sphenoidal approach with a success rate of 84.6% after a mean follow-up of 24.5 months. CONCLUSION: IPSS is generally treated with a sphenoidotomy approach, although in selected cases, a TPA should be preferred to expose the whole SS lateral wall though allowing a complete pedicled oriented resection of the tumor.

Segmentation of incident lacunes during the course of ischemic cerebral small vessel diseases.

Background: Lacunes represent key imaging markers of cerebral small vessel diseases (cSVDs). During their progression, incident lacunes are related to stroke manifestations and contribute to progressive cognitive and/or motor decline. Assessing new lesions has become crucial but remains time-consuming and error-prone, even for an expert. We, thus, sought to develop and validate an automatic segmentation method of incident lacunes in CADASIL caused by cysteine mutation in the EGFr domains of the NOTCH3 gene, a severe and progressive monogenic form of cSVD. Methods: Incident lacunes were identified based on difference maps of 3D T1-weighted MRIs obtained at the baseline and 2 years later. These maps were thresholded using clustering analysis and compared with results obtained by expert visual analysis, which is considered the gold standard approach. Results: The median number of lacunes at the baseline in 30 randomly selected patients was 7 (IQR = [2, 11]). The median number of incident lacunes was 2 (IQR = [0, 3]) using the automatic method (mean time-processing: 25 s/patient) and 0.5 (IQR = [0, 2]) using the standard visual approach (mean time-processing: 8 min/patient). The complementary analysis of segmentation results is enabled to quickly remove false positives detected in specific locations and to identify true incident lesions not previously detected by the standard analysis (2 min/case). A combined approach based on automatic segmentation of incident lacunes followed by quick corrections of false positives allowed to reach high individual sensitivity (median at 0.66, IQR = [0.21, 1.00]) and global specificity scores (0.80). Conclusion: The automatic segmentation of incident lacunes followed by quick corrections of false positives appears promising for properly and rapidly quantifying incident lacunes in large cohorts of cSVDs.

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.

Management strategies in clival and craniovertebral junction chordomas: a 29-year experience.

OBJECTIVE: Chordomas represent one of the most challenging subsets of skull base and craniovertebral junction (CVJ) tumors to treat. Despite extensive resection followed by proton-beam radiation therapy, the recurrence rate remains high, highlighting the importance of developing efficient treatment strategies. In this study, the authors present their experience in treating clival and CVJ chordomas over a 29-year period. METHODS: The authors conducted a retrospective study of clival and CVJ chordomas that were surgically treated at their institution from 1991 to 2020. This study focuses on three aspects of the management of these tumors: the factors influencing the extent of resection (EOR), the predictors of survival, and the outcomes of the endoscopic endonasal approaches (EEAs) compared with open approaches (OAs). RESULTS: A total of 265 surgical procedures were performed in 210 patients, including 123 OAs (46.4%) and 142 EEAs (53.6%). Tumors that had an intradural extension (p = 0.03), brainstem contact (p = 0.005), cavernous sinus extension (p = 0.004), major artery encasement (p = 0.01), petrous apex extension (p = 0.003), or high volume (p = 0.0003) were significantly associated with a lower EOR. The 5-year progression-free survival (PFS) and overall survival (OS) rates were 52.1% and 75.1%, respectively. Gross-total resection and Ki-67 labeling index < 6% were considered to be independent prognostic factors of longer PFS (p = 0.0005 and p = 0.003, respectively) and OS (p = 0.02 and p = 0.03, respectively). Postoperative radiation therapy correlated independently with a longer PFS (p = 0.006). Previous surgical treatment was associated with a lower EOR (p = 0.01) and a higher rate of CSF leakage after EEAs (p = 0.02) but did not have significantly lower PFS and OS compared with primary surgery. Previously radiation therapy correlated with a worse outcome, with lower PFS and OS (p = 0.001 and p = 0.007, respectively). EEAs were more frequently used in patients with upper and middle clival tumors (p = 0.002 and p < 0.0001, respectively), had a better rate of EOR (p = 0.003), and had a lower risk of de novo neurological deficit (p < 0.0001) compared with OAs. The overall rate of postoperative CSF leakage after EEAs was 14.8%. CONCLUSIONS: This large study showed that gross-total resection should be attempted in a multidisciplinary skull base center before providing radiation therapy. EEAs should be considered as the gold-standard approach for upper/middle clival lesions based on the satisfactory surgical outcome, but OAs remain important tools for large complex chordomas.

Typical and Atypical Symptoms of Petrous Apex Cholesterol Granuloma: Association with Radiological Findings.

Objective: Petrous apex cholesterol granuloma (PACG) is a lesion that can give rise to different symptoms, and correlations with etiopathology are ambiguous. The aim of this study is to analyze the association between PACG symptoms and radiological findings at presentation, in order to establish a reproduceable pre-operative radiological evaluation and guide the surgical indication. Methods: PACG patients were collected in two tertiary care hospitals. All cases underwent CT/MRI to evaluate the cyst localization and erosion of surrounding structures. Typical and atypical symptoms were then analyzed and compared to radiologic findings established in accordance with the literature. Results: Twenty-nine patients were recruited; the most common symptoms were headache (69%), diplopia (20.7%) and fainting (24.1%), an atypical clinical manifestation related to jugular tubercle involvement. Significant associations between symptoms and radiologic findings were noted in terms of headache and temporal lobe compression (p = 0.04), fainting and jugular tubercle erosion (p < 0.001), vestibular symptoms and internal auditory canal erosion (p = 0.02), facial paresthesia and Meckel's cave compression (p = 0.03), diplopia and Dorello canal involvement (p = 0.001), and tinnitus and cochlear basal turn erosion (p < 0.001). All patients were treated via an endoscopic−endonasal approach, in which extension was tailored to each case. At a median follow-up of 46 months, 93.1% of patients experienced resolution of symptoms. Conclusions: This clinico-radiological series demonstrates associations between symptoms and anatomical subsites involved with PACG. Hence, it may guide the surgeon at the time of surgical decision, since it asserts that typical and atypical symptoms are actually related to PACG.

Management of Nasopharyngeal Cyst of Second Branchial Cleft Origin: Case Series and Systematic Review.

Branchial cyst of the second pouch is the most common lesion of the nasopharyngeal lateral wall, generally localized between the pharyngeal wall and internal carotid artery. Cases consistent with such lesion, were collected. Symptomatic patients were treated with endoscopic trans-nasal marsupialisation, asymptomatic cases were followed-up. Among the 10 patients included, 4 were symptomatic and accordingly treated. In the literature, 36 cases were found, all of which were treated, most commonly with a total excision. Considering the benign nature of branchial nasopharyngeal cyst, its treatment should be tailored to each patient: endoscopic marsupialization in symptomatic lesion, follow-up in asymptomatic one. Laryngoscope, 132:1904-1908, 2022.

Imaging of Skull Base and Orbital Invasion in Sinonasal Cancer: Correlation with Histopathology.

BACKGROUND: Pretreatment assessment of local extension in sinonasal cancer is essential for prognostic evaluation and surgical planning. The aim of this study was to assess the diagnostic performance of two common imaging techniques (CT and MRI) for the diagnosis of skull base and orbital invasion by comparing imaging findings to histopathological data. METHODS: This was a retrospective two-center study including patients with sinonasal cancer involving the skull base and/or the orbit operated on between 2000 and 2019. Patients were included only if pre-operative CT and/or MRI, operative and histopathologic reports were available. A double prospective blinded imaging review was conducted according to predefined radiological parameters. Radiologic tumor extension was compared to histopathological reports, which were considered the gold standard. The predictive positive value (PPV) for the diagnosis of skull base/orbital invasion was calculated for each parameter. RESULTS: A total of 176 patients were included. Ethmoidal intestinal-type adenocarcinoma was the most common type of cancer (41%). The PPV for major modification of the bony skull base was 78% on the CT scan, and 89% on MRI. MRI signs of dural invasion with the highest PPVs were: contact angle over 45° between tumor and dura (86%), irregular deformation of dura adjacent to tumor (87%) and nodular dural enhancement over 2 mm in thickness (87%). Signs of orbital invasion had low PPVs (<50%). CONCLUSIONS: This retrospective study provides objective data about the diagnostic value of pretreatment imaging in patients with sinonasal cancer.

Tumor Growth Rate as a New Predictor of Progression-Free Survival After Chordoma Surgery.

BACKGROUND: Currently, different postoperative predictors of chordoma recurrence have been identified. Tumor growth rate (TGR) is an image-based calculation that provides quantitative information of tumor's volume changing over time and has been shown to predict progression-free survival (PFS) in other tumor types. OBJECTIVE: To explore the usefulness of TGR as a new preoperative radiological marker for chordoma recurrence. METHODS: A retrospective single-institution study was carried out including patients reflecting these criteria: confirmed diagnosis of chordoma on pathological analysis, no history of previous radiation, and at least 2 preoperative thin-slice magnetic resonance images available to measure TGR. TGR was calculated for all patients, showing the percentage change in tumor size over 1 mo. RESULTS: A total of 32 patients were retained for analysis. Patients with a TGR ≥ 10.12%/m had a statistically significantly lower mean PFS (P < .0001). TGR ≥ 10.12%/m (odds ratio = 26, P = .001) was observed more frequently in recurrent chordoma. In a subgroup analysis, we found that the association of Ki-67 labeling index ≥ 6% and TGR ≥ 10.12%/m was correlated with recurrence (P = .0008). CONCLUSION: TGR may be considered as a preoperative radiological indicator of tumor proliferation and seems to preoperatively identify more aggressive tumors with a higher tendency to recur. Our findings suggest that the therapeutic strategy and clinical-radiological follow-up of patients with chordoma can be adapted also according to this new parameter.

MRI contribution for the detection of endolymphatic hydrops in patients with superior canal dehiscence syndrome.

PURPOSE: Patients with superior semicircular canal dehiscence syndrome, which can only be treated by surgery, present cochleo-vestibular symptoms related to a third-mobile window but also endolymphatic hydrops. Since cVEMP and oVEMP are disturbed by the presence of the dehiscence, the aim of the study is to assess the value of MRI for the diagnosis of endolymphatic hydrops in patients with superior semicircular canal dehiscence syndrome in comparison with cVEMP and oVEMP. METHODS: In this retrospective cohort study we enrolled 33 ears in 24 patients with superior semicircular dehiscence syndrome who underwent a 4-h delayed intravenous Gd-enhanced 3D-FLAIR MRI and pure tone audiometry, cVEMP and oVEMP. For each patient MRI images were evaluated by two radiologists who used a compartmental endolymphatic hydrops grading system in comparison with cVEMP and oVEMP. RESULTS: Endolymphatic hydrops was found on MRI in 9 out of 33 SCDS ears (27.3%). We found no significant correlation between the presence of endolymphatic hydrops on MRI and cVEMP and oVEMP (p = 0.36 and p = 0.7, respectively). However, there was a significant correlation between the presence of endolymphatic hydrops on MRI and the degree of sensorineural hearing loss, Air Conduction-Pure Tone Average level (p = 0.012) and Bone Conduction-Pure Tone Average level (p = 0.09), respectively. CONCLUSION: We demonstrated that EH might be observed in 27.3% of superior semicircular dehiscence syndrome ears. The role of inner ear MRI is important to detect endolymphatic hydrops, since cVEMP and oVEMP are disturbed by the presence of the dehiscence, because these patients could benefit from a medical treatment. LEVEL OF EVIDENCE: Level 3.

Isolated enhancement of the superior semi-circular canal on inner ear MRI: acute vestibular syndrome or superior semi-circular canal dehiscence?

PURPOSE: Recently, it has been reported that patients with acute vestibular syndrome (AVS) could present a marked enhancement of the semi-circular canals, involving mostly the superior semi-circular canals on delayed inner ear MRI. METHODS: We reported one patient having AVS and another one having superior semi-circular canal dehiscence syndrome (SCDS) who underwent delayed inner ear MRI performed 4 h after contrast media administration. RESULTS: On delayed inner ear MRI, a marked enhancement of the superior semi-circular canal was observed in both patients. Although the clinical presentation is clearly not the same, the co-existence between these two disorders is possible. For this reason, in patients with AVS, the presence of a marked enhancement of the superior semi-circular canal should rule out the presence of a co-existing SCDS on temporal bone CT, particularly if the patient reported cochlear symptoms such as pulsatile tinnitus and/or autophony. CONCLUSION: To our knowledge, this is the first report showing this finding on delayed inner ear MRI in a patient with SCDS. In AVS patients, this radiological anomaly could be particularly disturbing and should rule out the presence of a co-existing SCDS.

Multimodal strategy for the management of sphenoid osteoradionecrosis: Preliminary results.

OBJECTIVE: Osteoradionecrosis (ORN) of the sphenoid is a rare but potentially lethal complication that can occur after irradiation of nasopharyngeal and clival malignancies. The objective of this study was to describe a multimodal treatment strategy tailored to the clinical signs and to the radiological extent of the disease, and to report on its preliminary results. METHODS: Retrospective monocentric study at a tertiary skull base center. Patients treated for a sphenoid ORN from January 2014 to August 2018 were identified and charts were retrospectively reviewed for demographics, histologic tumor type, previous treatments of the tumor, clinical signs at presentation, radiological data, treatment, and outcomes. Sphenoid ORN was treated by a combination of medical therapy, endovascular treatment, and/or surgery. The use of each of these therapeutic modalities was based on the extent of ORN and on the presenting signs. RESULTS: Seven patients were included: four patients underwent endovascular treatment with occlusion of the internal carotid artery, five patients underwent surgical debridement, and covering of the exposed bone by a local flap, seven patients received antibiotics (in combination with pentoxyphilline, tocopherol, and clodronate in one case). Three patients died after progression of the ORN. The global survival rate was 57% (4/7) with a mean follow-up of 24 months. In one case, ORN was treated successfully by medical treatment only, with a combination of antibiotics, pentoxyphilline, tocopherol, and clodronate. CONCLUSION: This retrospective study describes the results of a management strategy adapted to the extent of the disease in sphenoid ORN and based on medical therapy only, or on a combination of medical therapy, interventional radiology, and/or surgery. LEVEL OF EVIDENCE: 4.

Electrophysiological and inner ear MRI findings in patients with bilateral vestibulopathy.

PURPOSE: Bilateral vestibulopathy (BV) is an uncommon disorder and the etiology remained idiopathic in most cases. Delayed 3D-FLAIR sequences have provided new insights into various inner ear diseases, allowing the evaluation of the endolymphatic space and the permeability of the blood-labyrinthine barrier (BLB). The aim of this study was to assess both the morphology of the endolymphatic space and the permeability of the BLB in patients with BV as evaluated by delayed 3D-FLAIR sequences. METHODS: In this retrospective study, we performed 3D-FLAIR sequences 4 h after administering contrast media to 42 patients with BV. Two radiologists independently evaluated the morphology of the endolymphatic space (either vestibular atelectasis or endolymphatic hydrops) and the permeability of the BLB. RESULTS: Morphologic anomalies of the endolymphatic space and vestibular blood-labyrinthine barrier impairment were observed in 59.6% of patients with BV. Bilateral vestibular atelectasis (VA) was found in 21 patients (50%), involving only the utricle and all three ampullas while the saccule was always observed with no sign of collapse: idiopathic BV (n = 19), aminoglycoside administration (n = 1) and few days following abdominal surgery (n = 1). One patient had bilateral vestibular malformation. BLB impairment was observed in five patients (11.9%): paraneoplastic (n = 1), lymphoma (n = 1), autoimmune (n = 1), and vestibular "neuritis" (n = 2). Seventeen patients (40.4%) had normal MRI with no endolymphatic space anomaly or BLB impairment. CONCLUSION: Patients with BV presented with morphologic anomalies of the endolymphatic space or BLB impairment in 59.6% of patients.

Clinical and radiological characteristics of patients with collapse or fistula of the saccule as evaluated by inner ear MRI.

Background: Delayed 3D-FLAIR sequences enable the distinction between the utricle and the saccule.Aims/objectives: We sought to evaluate the clinical and radiological findings in patients with no visible saccule (NVS) on 4-hour post-contrast MRI.Material and Methods: We retrospectively assessed the presence of NVS signs in 400 patients who underwent delayed inner ear MRI.Results: We reported on 28 patients with NVS. Among this group, on the NVS affected side: 14 had isolated sensorineural hearing loss (SNHL); 4 had fluctuating cochleo-vestibular disease; 3 had definite Menière's disease; 3 had Minor syndrome; 2 had delayed endolymphatic hydrops (EH); 2 had inner ear malformations; 1 had sudden cochleo-vestibular deficit following stapes surgery; 1 had a perilymphatic fistula and 1 had a contralateral fluctuating SNHL. Sixteen out of these 28 patients (57.1%) had cochlear hydrops on the same side as the NVS, while 10 patients (35.7%) had saccular hydrops on the contralateral side. Moreover, isolated blood labyrinth barrier (BLB) impairment on the NVS side was observed in 7 patients. Two patients (7.1%) had large vestibular aqueduct and NVS on the same side and one patient had perilymphatic fistula.Conclusions and significance: NVS seems to be multifactorial and could be linked to hydropic ear disease, third-mobile window pathologies and congenital malformation.

Development of a Novel Orthotopic Primary Human Chordoma Xenograft Model: A Relevant Support for Future Research on Chordoma.

Chordomas are slow-growing rare malignant neoplasms. The aim of this study was to establish a primary model of chordoma in the lumbosacral orthotopic area, to compare the growth rate to the subcutaneous site, and to show that this new graft site optimizes tumor growth and bony invasion. Eleven chordoma samples were transplanted subcutaneously in the flank and/or in contact with the lumbosacral region and grown into nude mice. Engraftment rate was significantly more successful in the lumbosacral environment compared with the flank at P0. Two xenografts from 2 patients showed bone invasion. One tumor was maintained through multiple rounds of serial transplantation, creating a model for study. Histological and immunostaining analysis confirmed that tumor grafts recapitulated the primary tumor from which they were derived, consisting of a myxoid chordoma expressing brachyury, cytokeratin AE1, EMA, and VEGF. Clear destruction of the bone by the tumor cells could be demonstrated. Molecular studies revealed PIK3CA and PTEN mutations involved in PI3K signaling pathway and most of the frequently reported chromosomal alterations. We present a novel orthotopic primary xenograft model of chordoma implanted for the first time in the lumbosacral area showing bone invasion, PIK3CA, and PTEN mutations that will facilitate preclinical studies.

Predictors of clinical or cerebral lesion progression in adult moyamoya angiopathy.

OBJECTIVE: To identify independent predictors of clinical or cerebral lesion progression in a large sample of adult patients with moyamoya angiopathy (MMA) prior to decisions regarding revascularization surgery. METHODS: Ninety participants (median age, 37.5 years) were assessed at baseline and followed for a median time of 42.8 months. Incident ischemic and hemorrhagic strokes, death, as well as any incident ischemic and hemorrhagic lesions on MRI were recorded. Multiple demographic, clinical, and cerebral imaging measures at baseline were considered as potential predictors of clinical or cerebral tissue change at follow-up. Data were analyzed based on the Andersen-Gill counting process model, followed by internal validation of the prediction model. RESULTS: Among multiple potential predictive measures considered in the analysis, Asian origin, a history of TIAs, and a reduction in hemodynamic reserve, as detected by imaging, were found to be significantly associated with an increased risk of combined clinical and imaging events. While the model estimated the risk of clinical or cerebral lesion progression to be approximately 0.5% per year when none of these factors was present, this risk exceeded 20% per year when all factors were present. CONCLUSION: A simple combination of demographic, clinical, and cerebral perfusion imaging measures may aid in predicting the risk of incident stroke and cerebral lesion progression in adult patients with MMA. These results may help to improve therapeutic decisions and aid in the design of future trials in adults with this rare condition.

Surgery and protontherapy in Grade I and II skull base chondrosarcoma: A comparative retrospective study.

OBJECTIVE: Skull base chondrosarcoma is a rare tumour usually treated by surgery and proton therapy. However, as mortality rate is very low and treatment complications are frequent, a less aggressive therapeutic strategy could be considered. The objective of this study was to compare the results of surgery only vs surgery and adjuvant proton therapy, in terms of survival and treatment adverse effects, based on a retrospective series. METHODS: Monocentric retrospective study at a tertiary care centre. All patients treated for a skull base grade I and II chondrosarcoma were included. We collected data concerning surgical and proton therapy treatment and up-to-date follow-up, including Common Terminology Criteria for Adverse Events (CTCAE) scores. RESULTS: 47 patients (23M/24F) were operated on between 2002 and 2015; mean age at diagnosis was 47 years-old (10-85). Petroclival and anterior skull base locations were found in 34 and 13 patients, respectively. Gross total resection was achieved in 17 cases (36%) and partial in 30 (64%). Adjuvant proton therapy (mean total dose 70 GyRBE,1.8 GyRBE/day) was administered in 23 cases. Overall mean follow-up was 91 months (7-182). Of the patients treated by surgery only, 8 (34%) experienced residual tumour progression (mean delay 51 months) and 5 received second-line proton therapy. Adjuvant proton therapy was associated with a significantly lower rate of relapse (11%; p = 0.01). There was no significant difference in 10-year disease specific survival between patients initially treated with or without adjuvant proton therapy (100% vs 89.8%, p = 0.14). Difference in high-grade toxicity was not statistically significant between patients in both groups (25% (7) vs 11% (5), p = 0.10). The most frequent adverse effect of proton therapy was sensorineural hearing loss (39%). CONCLUSION: Long-term disease specific survival was not significantly lower in patients without adjuvant proton therapy, but they experienced less adverse effects. We believe a surgery only strategy could be discussed, delaying as much as possible proton therapy in cases of relapse. Further prospective studies are needed to validate this more conservative strategy in skull base chondrosarcoma.

Aneurysmal bone cyst of the frontal bone - A radiologic-pathologic correlation.

We present a case of 27-year-old female who presented for a progressive frontal swelling with ipsilateral headache. Subsequent CT scan revealed an extradural and expansile multiloculated mass with thin and strongly enhanced septations and MRI evaluation showed internal hyperintensity on T2 with no restriction of diffusion and confirmed the multiple cystic spaces with enhancing septations and rare hemorrhagic fluid-fluid levels. Surgery was performed and diagnosis of aneurysmal bone cyst was made on frozen section. Identification of USP6 fusion gene by in situ hybridization technique permitted to confirm the diagnosis of primary ABC. Although aneurysmal bone cyst (ABC) of the skull is a very rare entity and accounts for 2-6% of all ABCs, we should think about it in front of osteolytic and cystic skull changes even with very few fluid-fluid levels. Following description of our case and differential diagnoses, we conduct a literature review of skull ABCs imaging characteristics and discuss the interest of USP6 rearrangement identification.