Malignant pheochromocytoma (PCC) and paraganglioma (PGL) are mostly caused by germline mutations of SDHB, encoding a subunit of succinate dehydrogenase. Using whole-exome sequencing, we recently identified a mutation in the FH gene encoding fumarate hydratase, in a PCC with an 'SDH-like' molecular phenotype. Here, we investigated the role of FH in PCC/PGL predisposition, by screening for germline FH mutations in a large international cohort of patients. We screened 598 patients with PCC/PGL without mutations in known PCC/PGL susceptibility genes. We searched for FH germline mutations and large deletions, by direct sequencing and multiplex ligation-dependent probe amplification methods. Global alterations in DNA methylation and protein succination were assessed by immunohistochemical staining for 5-hydroxymethylcytosine (5-hmC) and S-(2-succinyl) cysteine (2SC), respectively. We identified five pathogenic germline FH mutations (four missense and one splice mutation) in five patients. Somatic inactivation of the second allele, resulting in a loss of fumarate hydratase activity, was demonstrated in tumors with FH mutations. Low tumor levels of 5-hmC, resembling those in SDHB-deficient tumors, and positive 2SC staining were detected in tumors with FH mutations. Clinically, metastatic phenotype (P = 0.007) and multiple tumors (P = 0.02) were significantly more frequent in patients with FH mutations than those without such mutations. This study reveals a new role for FH in susceptibility to malignant and/or multiple PCC/PGL. Remarkably, FH-deficient PCC/PGLs display the same pattern of epigenetic deregulation as SDHB-mutated malignant PCC/PGL. Therefore, we propose that mutation screening for FH should be included in PCC/PGL genetic testing, at least for tumors with malignant behavior.
The association of ciprofloxacin and ceftazidime was efficient in countering the increasing resistance of P. aeruginosa to quinolones. We propose a prognostic classification of necrotizing external otitis based on the presence of facial paralysis and/or systemic factors.
Objective: To describe the presentation of intralabyrinthine schwannomas (ILSs). Study Design and Setting: Retrospective multicenter study involving 12 European skull base surgery tertiary referral centers. Patients: One hundred ten patients with the diagnosis of ILS, either labyrinth confined or extending into the internal auditory meatus for less than 50% of their volume. Main Outcome Measures: Data collected were age, sex, nature and timing of presenting symptoms, hearing (according to the AAO-HNS grading system), results of vestibular tests (caloric tests and cervical vestibular-evoked myogenic potentials [cVEMPs]), and tumor localization. Presenting symptoms and laboratory test results were studied according to the extension of the lesion into the cochlea (C) and vestibule (V), on one hand, and according to unifocal (L1) or plurifocal (L2) extension into the labyrinth, on the other. Results: Intracochlear type was more common (50%) than vestibular (19.1%) and more diffuse forms (30.9%). The mean delay for diagnosis was long (72.5 mo; SD, 76.6). Mean age was 53.9 years (SD, 13.2). Deafness was the most common symptom (77.8 dB HL [SD, 33.6], with only 24.6% of patients keeping viable hearing. Caloric tests (65.5% of patients) were abnormal in 77.8% of cases. c-VEMPs were abnormal in 65.7% of the 36 cases analyzed. In V forms, hearing was significantly better (class A + B in 21.1% in C and 45.8% in V forms) (p = 0.03), and vestibular function was more altered (C: 57%, V: 100%, p = 0.0009*). L2 forms were diagnosed later (L1: 59.1 mo, L2: 104.5 mo; p = 0.004*) and were associated more frequently with a dead ear (L1: 13.1%, L2: 41.2%, p = 0.002*) than L1 forms. Conclusions: This series, which is the largest in the literature, demonstrates that even very small and localized ILSs heavily compromise labyrinthine functions. Key Words: DizzinessV Intracochlear schwannomaVIntralabyrinthine schwannomaV Sensorineural hearing lossVTumor of the earVVestibular schwannoma.
The present systematic review and meta-analysis, based on the currently available evidence, suggests that corticosteroids improve only the caloric extent and recovery of canal paresis of patients with vestibular neuritis. At present, clinical recovery does not seem be better in patients receiving corticosteroids.
The objective of this study is to report the surgical outcome after middle fossa approach (MFA) plugging in patients suffering from a superior semi-circular canal dehiscence (SCD) syndrome. This is a retrospective case review. Tertiary referral center. Sixteen ears in 13 patients with a SCD syndrome suffering from severe and disabling vestibular symptoms with a bony dehiscence on CT scan >3 mm and decreased threshold of cervical vestibular evoked potentials (cVEMPs). We assessed preoperatively: clinical symptoms, hearing, cVEMPs threshold, size of dehiscence and videonystagmography (VNG) with caloric and 100 Hz vibratory tests. Postoperatively, we noted occurrences of neurosurgical complication, evolution of audiological and vestibular symptoms, and evaluation of cVEMP data. Tullio’s phenomenon was observed in 13 cases (81.3 %) and subjectively reported hearing loss in seven (43.7 %). All patients were so disabled that they had to stop working. No neurosurgical complications were observed in the postoperative course. In three cases (16.6 %), an ipsilateral and transitory immediate postoperative vestibular deficit associated with a sensorineural hearing loss (SNHL) was noted, which totally resolved with steroids and bed rest. All patients were relieved of audiological and vestibular symptoms and could return to normal activity with a mean follow-up of 31.1 months (range 3–95). No patient had residual SNHL. cVEMPs were performed in 14 ears postoperatively and were normalized in 12 (85.7 %). Two of the three patients operated on both sides kept some degree of unsteadiness and oscillopsia. MFA plugging of the superior semi-circular canal is an efficient and non-hearing deteriorating procedure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.