Skull Base Lesions Research Articles

Application of microprobe vascular Doppler in the operation of skull base lesions

Objective To investigate the effect of microprobe vascular Doppler (MVD) on the operation of skull base lesions. Methods From September 2017 to September 2018, 13 patients with skull base lesions at Neurosurgery Department of the first Affiliated Hospital of Soochow University were retrospectively analyzed. The 13 cases included 6 cases of meningioma in Sellar region, 2 cases of meningioma in petroclival region, 3 cases of pituitary adenoma of Knosp Ⅲ-Ⅳ grade, 1 case of chordoma in Sellar clival region, and 1 case of invasive growth of granulation tissue in intraorbital, skull base, sphenoid and ethmoid sinus after Aspergillus infection. The surgical methods included neuroendoscopic transnasal approach and microsurgical resection under craniotomy microscope. MVD was applied in all operations of this series. Medical imaging examination and follow-up were performed after operation. Results Among the 13 patients, total resection of meningioma in Sellar region was performed in 6 cases and subtotal resection in 2, total resection of Knosp grade Ⅲ-Ⅳ pituitary adenoma was conducted in 2 and subtotal resection in 1. Total resection was performed in 1 case of invasive growth of granulation tissue in intraorbital, skull base, sphenoid and ethmoid sinus after Aspergillus infection and 1 case of chordoma in Sellar base clival region. Uncorrected left eye vision was reported in the patient with Aspergillus infection post surgery. Postoperative symptoms of the other patients were improved. The prolactin level of 1 patient with prolactin adenoma was more than 204 ng/ml before operation. At 2 months post operation, the prolactin level was 105.66 ng/ml after oral bromocriptine combined with radiotherapy. The last reexamination was 11.3 ng/ml without hypophysis dysfunction. Six patients had varying degrees of electrolyte disorder after operation. Four patients had fever after operation and all returned to normal before discharge from hospital after treatment. All patients were followed up for (16.1±3.3) months(10-22 months), and there was no recurrence in imaging examination. Conclusion With the aid of MVD during the surgical resection of invasive growth lesions and large space occupying lesions in the skull base, the important blood vessels invaded, wrapped, pushed and displaced by the lesions can be monitored in real time, which might help avoid the disastrous consequences during and after operation and reduce the risk of surgery. Key words: Skull base neoplasms; Microsurgery; Natural orifice endoscopic surgery; Microprobe vascular Doppler

Effects of nasal lavage with and without mupirocin after endoscopic endonasal skull base surgery: a randomised, controlled study.

Nasal lavage with mupirocin has the potential to reduce sinonasal morbidity in endoscopic endonasal approaches for skull base surgery. To evaluate the effects of nasal lavage with and without mupirocin after endoscopic endonasal skull base surgery. A pilot randomised, controlled trial was conducted on 20 adult patients who had undergone endoscopic endonasal approaches for skull base lesions. These patients were randomly assigned to cohorts using nasal lavages with mupirocin or without mupirocin. Patients were assessed in the out-patient clinic, one week and one month after surgery, using the 22-item Sino-Nasal Outcome Test questionnaire and nasal endoscopy. Patients in the mupirocin nasal lavage group had lower nasal endoscopy scores post-operatively, and a statistically significant larger difference in nasal endoscopy scores at one month compared to one week. The mupirocin nasal lavage group also showed better Sino-Nasal Outcome Test scores at one month compared to the group without mupirocin. Nasal lavage with mupirocin seems to yield better outcomes regarding patients' symptoms and endoscopic findings.

Surgical Landmarks of the Endoscopic Transcanal Transcochlear Approach: A Cadaveric Study

BackgroundThe lateral skull base lesions are one of the most challenging parts of the head and neck. Surgical approaches for this area are complex and difficult. Although endoscopic approaches in skull base surgeries have progressed dramatically in recent years, there are few studies concerning these approaches.ObjectivesThis study aimed to describe the endoscopic transcanal transcochlear approach (ETTA) to reach the internal auditory canal (IAC) in the cadaveric temporal bone specimen.MethodsFirst, pre- and post-operative high resolution computed tomography (HRCT) images of the transcanal transcochlear pathway were obtained and 3D segmentation was performed using 3D Slicer software. The anatomic landmarks were identified using the endoscopic approach with and without navigation guide. Surgeries were done and the feasibility and challenges were evaluated.ResultsThe internal auditory canal (IAC) was accessed via the ETTA. Anatomic landmarks were looked and a surgical corridor was identified with HRCT segmentations and images obtained during surgery.ConclusionsWe tried to increase our learning curve and extend surgical experience in lateral skull base surgery via minimally invasive ETTA. The increased endoscopic skills and the use of auxiliary tools such as a navigation guide may be helpful for successful access to the lateral skull base.

Benign and inflammatory lesions of the skull base

Avariety of tumors, tumor-like non-neoplastic and inflammatory lesions occur in the skull base. Awide variety of diseases and lesions complicate the process of radiological diagnosis. The main task of imaging consists of the recognition and characterization of skull base lesions with detailed description of the extent of infiltration of adjacent structures, which is important for preoperative planning. Computed tomography (CT) and magnetic resonance imaging (MRI) are the preferred modalities for evaluating cranial base lesions. Above all, they depict more accurately the involvement of bones, vascular and nerve structures. MRI, especially T1-weighted sequences, provide superior contrast to CT soft tissue, which is useful for detecting lesions surrounded by high-fat bone marrow. T2-weighted MRI imaging is useful for characterizing watery tumor tissue/edema or cystic portions of the lesions. CT outperforms MRI in assessing the presence of calcification and osseous destruction. Knowledge of the clinical symptoms, as well as the overview of possible variants of the skull base lesions, aid in the diagnosis. The aim of this review is to present the most important benign and inflammatory lesions of the skull base as well as to investigate typical imaging phenomena of the most common lesions, and to provide insights into the most important anatomical landmarks of the skull base.

Editorial introductions

Editorial introductions

Skull Base Manifestations of Erdheim-Chester Disease: A Case Series and Systematic Review.

Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis. Up to 50% of patients develop central nervous system involvement, and a subset of these patients can present with isolated tumor-like masses. To describe the skull base manifestations of ECD with an emphasis on aspects most pertinent to surgeons who may be referred such patients for primary evaluation. Scopus, Web of Science, and PubMed were searched from database inception to May 1, 2018 for articles reporting skull base ECD. An institutional retrospective analysis of all patients treated at the authors' institution since January 1, 1996 was also performed to supplement these data. Of 465 retrieved articles, 18 studies totaling 20 patients met inclusion criteria. Institutional review identified an additional 7 patients. Collectively, the median age at diagnosis was 49 yr (interquartile range, 42-58) with a 4:1 male-to-female ratio. Patients frequently presented with diplopia (48%), headache (30%), dysarthria (22%), and vertigo or imbalance (22%), though trigeminal hypesthesia (11%), facial nerve paresis (7%), hearing loss (7%), and trigeminal neuralgia (7%) were also observed. ECD commonly mimicked meningioma (33%), trigeminal schwannoma (8%), neurosarcoidosis (8%), and skull base lymphoma (8%). Discrete skull base lesions frequently mimic more common pathology such as meningioma or cranial nerve schwannomas. Medical therapy comprises the initial treatment for symptomatic skull base disease. Surgical resection is not curative and the utility of surgical intervention is largely limited to biopsy to establish diagnosis and/or surgical debulking to relieve mass effect.

Endoscopic transmastoid posterior petrosal approach for locally aggressive tumors in the petrous part of the temporal bone involving the internal auditory canal, jugular foramen, and hypoglossal canal.

The posterior petrosal approach is an established surgical method offering wide access to skull base lesions through mastoid air cells. The authors describe their experience with the endoscopic transmastoid "posterior petrosal" approach (EPPAP) for skull base tumors involving the internal auditory canal (IAC), jugular foramen, and hypoglossal canal. The EPPAP was performed for 7 tumors (3 chordomas, 2 chondrosarcomas, 1 schwannoma, and 1 solitary fibrous tumor). All surgical procedures were performed under endoscopic visualization with mastoidectomy. The compact bone of the mastoid air cells and posterior surface of the petrous bone are carefully removed behind the semicircular canals. When removal of cancellous bone is extended superomedially through the infralabyrinthine space, the surgeon can expose the IAC and petrous portion of the internal carotid artery to reach the petrous apex (infralabyrinthine route). When removal of cancellous bone is extended inferomedially along the sigmoid sinus, the surgeon can safely reach the jugular foramen (transjugular route). Drilling of the inferior surface of petrous bone is extended further inferoposteriorly behind the jugular bulb to approach the hypoglossal canal and parapharyngeal space through the lateral aspect of the occipital condyle (infrajugular route). Of the 7 tumors, gross-total resection was achieved in 4 (57.1%), subtotal resection (> 95% removal) in 2 (28.6%), and partial resection (90% removal) in 1 (14.2%). Postoperatively, 2 of 3 patients with exudative otitis media showed improvement of hearing deterioration, as did 2 patients with tinnitus. Hypoglossal nerve palsy and swallowing difficulty were improved after surgery in 2 patients and 1 patient, respectively. In 1 patient with severe cranial nerve deficits before surgery, symptoms did not show any improvement. The authors present their preliminary experience with EPPAP for skull base tumors in the petrous part of the temporal bone and the lateral part of the occipital condyle involving the cranial nerves and internal carotid arteries. The microscope showed a higher-quality image and illumination in the low-power field. However, the endoscope could offer wider visualization of the surgical field and contribute to minimizing the size of the surgical pathways, necessity of brain retraction, and eventually the invasiveness of surgery. Thus, the EPPAP may be safe and effective for skull base tumors in the petrous region, achieving balance between the radicality and invasiveness of the skull base surgery.

Development, reliability, validity and sensitivity of the Sino-Nasal Outcome Test for Neurosurgery (SNOT-NC)

The transnasal endoscopic approach to lesions of the skull base has come into routine practice in recent years. Standardized questionnaires to assess the postoperative sequelae are missing. The authors present a custom-made questionnaire for the sino-nasal outcome test for neurosurgery (SNOT-NC) in accordance with the SNOT-22. The SNOT-NC was developed with respect to the German version of the Sino-Nasal Outcome Test (SNOT-22) which is used for patients suffering from rhinosinusitis. It consists of 23 items covering "Nasal Discomfort", Sleep Problems/Reduced Productivity", "Ear and Head Discomfort", "Visual Impairment" and "olfactory impairment". The SNOT-NC was specifically adapted to patients undergoing transnasal operations of skull base lesions. The Short Form 36 health survey (SF-36), a nasal ad hoc questionnaire and the "Sniffin' Sticks" test were used for analyzing convergent and divergent validity. The psychometric and clinimetric analyses were performed using the data of 102 consecutive patients treated by transnasal operations for skull base lesions. Factorial validity was secured by a confirmatory factor analysis. The internal consistency (Cronbach's Alpha) for the subscales ranged from .62 to .85, while it was .84 for the whole instrument. The Guttman's lower reliability limits range estimates corresponded closely to the Cronbach's Alpha coefficients obtained. Examination of convergent and divergent validity revealed substantial associations between the SNOT-NC and a wide range of related nasal symptoms (p < .05). Different aspects of sensitivity were analyzed statistically with Cohen's t statistic for change (pairwise t tests) exhibiting at least p < .05) underlining the sensitivity of the SNOT-NC. The SNOT-NC appears to be a valid, reliable and sensitive measure for assessing the clinical outcome of patients undergoing transnasal endoscopic skull base surgery. The SNOT-NC proved to be a valuable tool to assess the nasal discomfort outcome of patients at follow-up examinations. Further analyses encompassing analyses for retest reliability are called for the future.

Theragnostic Use of Radiolabelled Dota-Peptides in Meningioma: From Clinical Demand to Future Applications

Meningiomas account for approximately 30% of all new diagnoses of intracranial masses. The 2016 World Health Organization’s (WHO) classification currently represents the clinical standard for meningioma’s grading and prognostic stratification. However, watchful waiting is frequently the chosen treatment option, although this means the absence of a certain histological diagnosis. Consequently, MRI (or less frequently CT) brain imaging currently represents the unique available tool to define diagnosis, grading, and treatment planning in many cases. Nonetheless, these neuroimaging modalities show some limitations, particularly in the evaluation of skull base lesions. The emerging evidence supporting the use of radiolabelled somatostatin receptor analogues (such as dota-peptides) to provide molecular imaging of meningiomas might at least partially overcome these limitations. Moreover, their potential therapeutic usage might enrich the current clinical offering for these patients. Starting from the strengths and weaknesses of structural and functional neuroimaging in meningiomas, in the present article we systematically reviewed the published studies regarding the use of radiolabelled dota-peptides in surgery and radiotherapy planning, in the restaging of treated patients, as well as in peptide-receptor radionuclide therapy of meningioma.

Supraorbital Craniotomy for Large Anterior Skull Base Meningiomas: A Technical Note.

Background:Supraorbital craniotomy (SOC) has brought a paradigm shift in approaching anterior skull base lesions. With better understanding of relevant anatomy, the indications are being stretched from highly selected, small-to-moderate-sized tumors to large and complex anterior skull base lesions.Objective:We share our experience and discuss the nuances of surgery for large anterior skull base meningiomas using the SOC.Methods:This is a single institute study using prospectively collected retrospective data from seven cases of large anterior skull base meningiomas (>3 cm) using the SOC. We reviewed the indications, safety, and procedural complications in these cases.Results:Simpson's Grade 2 excision was achieved in all these seven cases, with faster postoperative recovery. Follow-up clinical outcome and cosmesis were satisfactory.Conclusion:SOC is a safe alternative for the standard skull base approaches in treating large anterior skull base meningiomas. The SOC can be effectively used to treat selected large anterior skull base meningiomas.

Seizure Risk following Open and Expanded Endoscopic Endonasal Approaches for Intradural Skull Base Tumors.

Objectives The incidence of seizures following a craniotomy for tumor removal varies between 15 and 20%. There has been increased use of endoscopic endonasal approaches (EEAs) for a variety of intracranial lesions due to its more direct approach to these pathologies. However, the incidence of postoperative seizures in this population is not well described. Methods This is a single-center, retrospective review of consecutive patients undergoing EEA or open craniotomy for resection of a cranial base tumor between July 2007 and June 2014. Patients were included if they underwent an EEA for an intradural skull base lesion. Positive cases were defined by electroencephalograms and clinical findings. Patients who underwent a craniotomy to remove extra-axial skull base tumors were analyzed in the same fashion. Results Of the 577 patients treated with an EEA for intradural tumors, 4 experienced a postoperative seizure (incidence 0.7%, 95% confidence interval [CI]: 0.002-0.02). Over the same period, 481 patients underwent a craniotomy for a skull base lesion of which 27 (5.3%, 95% CI: 0.03-0.08) experienced a seizure after surgery. The odds ratio for EEA was 0.13 (95% CI: 0.05-0.35). Both populations were different in terms of age, gender, tumor histology, and location. Conclusion This study is the largest series looking at seizure incidence after EEA for intracranial lesions. Seizures are a rare occurrence following uncomplicated endonasal approaches. This must be tempered by selection bias, as there are inherent differences in which patients are treated with either approach that influence the likelihood of seizures.

Surgical Outcomes of the Endoscopic Endonasal Transsphenoidal Approach for Anterior Skull Base Lesions: Experience in Combined Military Hospital, Dhaka

Introduction:The endoscopic endonasal approach is a minimally invasive surgical technique for removal of skull base lesions by using nose and sinuses as natural corridors. This study represents our institutional experience with endoscopic endonasal trans-sphenoidal approach for anterior skull base lesions.&#x0D; Objective: To find out surgical outcomes of endoscopic endonasal trans-sphenoidal approach for treatment of anterior skull base lesions.&#x0D; Materials and Methods: Cross-sectional observational study of 38 consecutive patients who underwent endoscopic endonasal trans-sphenoidal surgery for anterior skull base lesions in Combined Military Hospital, Dhaka from July 2013 to June 2017.&#x0D; Results:This study included 16 men and 22 women, ranging from 24 to 68 years of age where median was 38 years. Common presentations were visual disorder (60%), headache (30%), features of pituitary apoplexy (5%), Cushing disease (0.35%), acromegaly (0.7 %), galactorrhoea (0.35%). Radiological evaluation revealed intrasellar (12), sellar and suprasellar (22), sellar and parasellar (1), tuberculum sella and planum sphenoidale (3), clival (1) lesions. Recurrent cases (3/38) were nonfunctioning pituitary macroadenoma, prolactinoma, and growth hormone secreting macroadenoma. The surgical resection in relation to post op imaging were 45% as gross total resection, near-total in 35%, subtotal in 15%, and partial in 5%. We found fifteen patients experienced improvement in visual acuity, while one patient worsened. Common complications were transient diabetes insipidus (53%), new pituitary deficit (35%), endonasal adhesions (20%), and cerebrospinal fluid leak (5%). Surgical mortality was (0.35%). The histological diagnoses included twenty-eight pituitary adenomas, five craniopharyngioma, three meningioma, one Rathke’s cleft cyst and one clival chordoma.&#x0D; Conclusion: Endoscopic endonasal transsphenoidal surgery is a valuable treatment option for an anterior skull base lesion.&#x0D; Journal of Armed Forces Medical College Bangladesh Vol.14(1) 2018: 66-68

Gamma Knife Radiosurgery for Primary and Secondary Trigeminal Neuralgia

Abstract INTRODUCTION Trigeminal neuralgia has always been a disease of conflict from pathological and management perspectives. Despite advances in the radiological imaging, evidence from autopsy studies, and intraoperative findings, concrete answers are not in sight. GKRS has been a strong contender among available treatment options for the management of trigeminal neuralgia. METHODS All patients were evaluated on clinical criteria, BNI scale for intensity of pain, and facial hypoesthesia (if any) in a protocol-based manner. Only patients with BNI III to V were offered GKRS as a treatment modality. The Marseille point was targeted with a 70 to 90 Gy dose at 50% isodose. Patients were informed about all available treatment options with long-term prognosis and pain control rates. Patients in need of an immediate pain relief, in failed GKRS, and in a severe pain jeopardizing routine life and eating habits were not offered GKRS and were managed with microvascular decompression. RESULTS A total of 108 (65 males, 43 females) patients received GKRS with the Perfexion model since 2009. Eighty-two percent of the patients received GKRS for primary trigeminal neuralgia, while the rest received GKRS for secondary trigeminal neuralgia due to skull base lesions (meningioma, schwannoma, cerebellar AVM, etc). A total of 78% of the patients had preoperative BNI scale IV, while 19% and 3% of the patients had grade III and V scale pain, respectively. Ninety-four percent patients gained BNI scale III intensity pain within 3 mo of GKRS. The 3-yr pain control rate (BNI I-II) could be attained in 81% of the patients. Twelve percent of the patients remained in BNI grade III. Two patients needed redo GKRS for their pain recurrence. CONCLUSION It remains uncontested that MVD provides the best long-term pain-free control in patients of trigeminal neuralgia; however, GKRS remains a valuable feasible option for a selected group of patients. GKRS should be offered as an alternative treatment modality in patients not in urgent need of pain relief. In failed GKRS, authors did not encounter any difficulty in microvascular decompression.

Minimally Invasive Endoscopic Keyhole Approach for Meningiomas

Abstract INTRODUCTION The advantages of neuroendoscopic surgery are wide viewing angle and freedom of axis of view with minimal surgical trauma. Taking advantage of the features of neuroendoscopy, the authors report the experience of minimally invasive endoscopic keyhole approach (EKA) for various meningiomas. METHODS A total of 28 cases of various type of meningiomas were treated by EKA from 2007 to 2018. A keyhole of about 2.5 cm was created according to the case, and tumor removal was performed using an endoscope and exoscope. The scope was held by a pneumatic holder controlled by the assistant to continue the procedure in a comfortable environment. RESULTS EKAs were performed for anterior skullbase lesions via eyebrow skin incision (n = 12), posterior fossa lesions including tentorial meningiomas, torcular meningiomas (n = 7), falcine lesions (n = 6), subtemporal approach (n = 2), enplaque convexity menigiomas (n = 1). All the tumors were resected as planned with minimum brain retraction and well-illuminated fine vision in deep corner. In the cases of a large tumor in the elderly, maximum internal decompression was performed, and the adhered tumor was left on the surface of the brain to avoid injury. The brain retraction was automatically limited by the small craniotomy, and excellent magnified image in deep corner was obtained by EKA. By eliminating the blind spots, radical resection is achieved. Also, in the aging society, depending on the patient with benign meningioma, it is important to consider what better treatment is, to alleviate symptoms and to coexist with the tumor. The cooperation of the assistant is important for this approach. To avoid the interference between the endoscope and the instrument, it is necessary to have a technique for moving the endoscope as needed in order to keep the fine visual field. CONCLUSION In the treatment of meningioma, the role of endoscopes is important in both the radicality obtained in a wide field of view and the less invasiveness in the aging society.

Management of Pediatric Sinonasal and Skull Base Lesions

Pediatric sinonasal and skull base lesions are rare and complex disorders. The safe and comprehensive management of this diverse group of pathologies requires the expertise of an experienced multidisciplinary skull base team. With significant evolution and improved outcomes achieved in adult endoscopic skull base surgery (ESBS), similar principles have been applied to the pediatric population. Pediatric endoscopic surgery for sinonasal and skull base tumors has therefore also evolved due to a variety of technologic and surgical advances, multidisciplinary team approaches, and continued innovation. Pediatric sinonasal and skull base tumors require complex multidisciplinary management for optimal outcome. Detailed understanding of the sinonasal anatomy will improve surgical outcomes. The surgical approaches and techniques are dependent on the location of the lesion, the pathology, extent of disease, and surgical goals. Reconstruction following tumor extirpation follows the same principles as adult reconstruction, with the ultimate goal of achieving a watertight seal that separates the nasal cavity from the brain. Complications can be catastrophic and rely on immediate recognition and management to prevent long-term sequelae.

Three-Dimensional Volume Rendering: An Underutilized Tool in Neurosurgery

Two-dimensional radiologic images of computed tomography (CT) and magnetic resonance imaging (MRI) examinations are insufficient to provide three-dimensional conception of intracranial or spinal lesions, especially for an inexperienced neurosurgeon. We share our experience of applications of volume rendering (VR) images of CT and MRI studies of brain and spine for the purpose of training and surgical planning in neurosurgery. Digital Imaging and Communications in Medicine viewer software was used on a personal computer/laptop to view CT and MRI examinations of various lesions of brain, spine, and spinal cord. Various user-friendly applications of the software enable users to edit the images acquired. Imaging technique (CT and MRI) incorporating continuous or overlapping slice with slice thickness of 1 mm with zero gap provides adequate three-dimensional image quality on personal computer/laptop acquired by VR. It was especially helpful for assessment of lesions of the skull base, intracranial vessels (aneurysm and arteriovenous malformation), craniovertebral junction and contrast-enhancing lesions of the brain. Displaying VR images in the operating room as per the patient's head position orients the surgeon to identify various structures in the surgical field. VR is underused in neurosurgery. It enables inexperienced neurosurgeons to understand morphologic details of a lesion and important osteoneurovascular structures around it. It is also helpful for training and preoperative planning in selected patients in neurosurgery.

Skull Base Enchondroma and Chondrosarcoma in Ollier Disease and Maffucci Syndrome

Maffucci syndrome (MS) and Ollier disease (OD) are rare diseases characterized by multiple benign enchondromas. The incidence of skull base (SB) enchondromas and the risk of malignant transformation remain unknown. Most SB lesions are asymptomatic, and surgical resection carries significant morbidity. Observation may be a reasonable strategy. We report our experience with observation of probable SB enchondromas in MS/OD patients. Retrospective review of OD/MS patients with cranial imaging between 1995 and 2018 at 1 institution. 14 patients were included: 3 with MS (21.4%) and 11 with OD (78.6%). The median age was 28 years (range, 11-74 years) and 57.1% were female. Extracranial chondrosarcoma was reported in 3 (21.4%) patients. Seven (50%) patients with SB enchondroma or chondrosarcoma were identified on initial imaging. In patients with SB lesions, the indications for imaging were headache (n=3), seizure (n=1), and diplopia (n=1); 2 cases were incidental findings. The most commonly involved structures were petroclival fissure (86%) and clivus (71%). Treatment included observation (6/7) and resection (1/7). Follow-up imaging was available for all SB lesions, with a mean interval of 50.7 months (range, 5-225 months) and was negative for progression in all patients. Primary SB lesions in OD/MS patients frequently present in the petroclival junction. Cranial screening and close observation should be considered in MS/OD patients, given the increased risk of intra-axial intracranial tumors, de novo chondrosarcomas, or malignant degeneration of previously known lesions. In asymptomatic patients, observation appears to be a safe strategy in this cohort. Further case accumulation and follow-up are required to better understand the long-term outcomes.

Clinical significance of IgG4 in sinonasal and skull base inflammatory pseudotumor.

Inflammatory pseudotumor (IPT) in the sinonasal cavity and skull base region is benign non-neoplastic inflammatory process. However, IPT can mimic malignant tumor or infectious disease and there are difficulties in confirmation of diagnosis. The aim of study is to evaluate the clinical significance of immunoglobulin G4 (IgG4) in IPT in terms of steroid response and differential diagnosis with other skull base infiltrative lesions. Medical records were reviewed retrospectively from 1998 to 2016. Subjects diagnosed with IPT by surgical biopsy were enrolled. IgG4 positivity was defined as IgG4/IgG ratio > 0.4. Additionally, IgG4/IgG ratio was calculated in eight skull base osteomyelitis (SBO) patients. Twenty-six IPT patients were included and the average age was 52.3years, and 57.7% were male and 42.3% were female. Most lesions were involved in the sinuses (88.5%) and the incidence of extension beyond the sinuses itself was as follows: the cheek/hard palate/parapharynx (15.4%), orbit (61.5%), skull base (57.7%), and dura or brain (23.1%). All IPT cases revealed IgG4 + plasma cells and IgG4/IgG ratio over 0.4 was detected in 42.3% (11/26) of cases. In case of SBO, no patients had IgG4/IgG ratio exceed 0.4. Main treatment modality was systemic steroids (61.5%) and other modalities were used: surgery (3.8%), immunosuppressant (7.7%), radiotherapy (30.8%), or a combination of these modalities (15.4%). Steroid responses were not significantly different, but IgG4-positive group tended to have better response to steroid therapy. IgG4-positive and IgG4-negative IPT patients revealed no differences in involvement sites, clinical course, and steroid responses. However, IgG4/IgG ratio and IgG4 + plasma cell count can provide a diagnostic clue for infiltrative skull base lesions such as IPT and a differential diagnosis of SBO.

Transnasal endoscopic approach for pediatric skull base lesions: a case series.

Transnasal endoscopic transsphenoidal approaches constitute an essential technique for the resection of skull base tumors in adults. However, in the pediatric population, sellar and suprasellar lesions have historically been treated by craniotomy. Transnasal endoscopic approaches are less invasive and thus may be preferable to craniotomy, especially in children. In this case series, the authors present their institutional experience with transnasal endoscopic transsphenoidal approaches for pediatric skull base tumors. The authors retrospectively reviewed pediatric patients (age ≤ 18 years) who had undergone transnasal endoscopic transsphenoidal approaches for either biopsy or resection of sellar or suprasellar lesions between 2007 and 2016. All operations were performed jointly by a team of pediatric neurosurgeons and skull base otolaryngologists, except for 8 cases performed by one neurosurgeon. The series included 42 patients between 4 and 18 years old (average 12.5 years) who underwent 51 operations. Headache (45%), visual symptoms (69%), and symptoms related to hormonal abnormalities (71%) were the predominant presenting symptoms. Improvement in preoperative symptoms was seen in 92% of cases. Most patients had craniopharyngiomas (n = 16), followed by pituitary adenomas (n = 12), Rathke cleft cysts (n = 4), germinomas (n = 4), chordomas (n = 2), and other lesion subtypes (n = 4). Lesions ranged from 0.3 to 6.2 cm (median 2.5 cm) in their greatest dimension. Gross-total resection was primarily performed (63% of cases), with 5 subsequent recurrences. Nasoseptal flaps were used in 47% of cases, fat grafts in 37%, and lumbar drains in 47%. CSF space was entered intraoperatively in 15 cases, and postoperative CSF was observed only in lesions with suprasellar extension. There were 8 cases of new hormonal deficits and 3 cases of new cranial nerve deficits. Length of hospital stay ranged from 1 to 61 days (median 5 days). Patients were clinically followed up for a median of 46 months (range 1-120 months), accompanied by a median radiological follow-up period of 45 months (range 3.8-120 months). Most patients (76%) were offered adjuvant therapy. In this single-institution report of the transnasal endoscopic transsphenoidal approach, the authors demonstrated that this technique is generally safe and effective for different types of pediatric skull base lesions. Favorable effects of surgery were sustained during a follow-up period of 4 years. Further refinement in technology will allow for more widespread use in the pediatric population.

Impact of 68Ga-DOTATOC PET/MRI on robotic radiosurgery treatment planning in meningioma patients: first experiences in a single institution.

OBJECTIVEFor stereotactic radiosurgery (SRS) planning, precise contouring of tumor boundaries and organs at risk is of utmost importance. Correct interpretation of standard neuroimaging (i.e., CT and MRI) can be challenging after previous surgeries or in cases of skull base lesions with complex shapes. The aim of this study was to evaluate the impact of 68Ga-DOTATOC PET/MRI on treatment planning for image-guided SRS by CyberKnife.METHODSThe authors retrospectively identified 11 meningioma treatments in 10 patients who received a 68Ga-DOTATOC PET/MRI prior to SRS. The planning target volume (PTV) used for the patients' treatment was defined as the reference standard. This was contoured by a treating radiosurgeon (RS0) using fused planning CT and PET/MRI data sets. The same tumors were then contoured by another experienced radiosurgeon (RS1) and by a less-experienced radiosurgeon (RS2), both blinded to PET data sets. A comparison of target volumes with focus on volume-based metrics and distance to critical structures was performed. RS1 and RS2 also filled in a questionnaire analyzing the confidence level and the subjective need for the implementation of PET data sets for contouring.RESULTSAnalysis showed a subjective personal preference for PET/MRI in all cases for both radiosurgeons, particularly in proximity to critical structures. The analysis of the planning volumes per physician showed significantly smaller RS2-PTV in comparison to RS1-PTV and to RS0-PTV, whereas the median volumes were comparable between RS1-PTV and RS2-PTV (median: RS0: 4.3 cm3 [IQR 3.4-6.5 cm3] and RS1: 4.5 cm3 [IQR 2.7-6 cm3] vs RS2: 2.6 cm3 [IQR 2-5 cm3]; p = 0.003). This was also reflected in the best spatial congruency between the 2 experienced physicians (RS0 and RS1). The percentage of the left-out volume contoured by RS1 and RS2 compared to RS0 with PET/MRI demonstrated a relevant left-out-volume portion in both cases with greater extent for the less-experienced radiosurgeon (RS2) (RS1: 19.1% [IQR 8.5%-22%] vs RS2: 40.2% [IQR 34.2%-53%]). No significant differences were detected regarding investigated critical structures.CONCLUSIONSThis study demonstrated a relevant impact of PET/MRI on target volume delineation of meningiomas. The extent was highly dependent on the experience of the treating physician. This preliminary study supports the relevance of 68Ga-DOTATOC PET/MRI as a tool for radiosurgical treatment planning of meningiomas.