Pseudomeningoceles of the sphenoid sinus masquerading as sinus pathology

Omentomyelopexy for the Treatment of a Persistent Lumbar Pseudomeningocele: A Case Report With Technical Note

BACKGROUND AND IMPORTANCE

Pseudomeningoceles are extradural accumulations of cerebrospinal fluid. In most cases, they appear as a complication of spinal operations. Omentomyelopexy is a surgery in which an autologous omentum flap is implanted over the dural opening. We describe a case of persistent pseudomeningocele treated with omentomyelopexy.

CLINICAL PRESENTATION

A 37-year-old man sustained a T12-L1 AO B3 fracture during a motorcycle accident. He underwent posterolateral fusion and then neurological rehabilitation. Two years later, however, his condition worsened, and he experienced progressive weakness-he was diagnosed with an intramedullary cyst, which was treated with laminectomy, arachnolysis and cystotomy. A pseudomeningocele developed afterward, and the patient underwent multiple reoperations in the following years, none of which were effective. Omentomyelopexy, a complex procedure aimed to facilitate cerebrospinal fluid absorption and subsequent formation of a permanent membrane, was offered to the patient as a "last resort." After undergoing omentomyelopexy, his pseudomeningocele resolved.

CONCLUSION

Although it should be reserved for exceptionally pertinent cases, omentomyelopexy is a viable option for managing persistent pseudomeningocele. However, further research is needed to better understand the effects and benefits of omentomyelopexy in this context.

Imaging the External Ear: Practical Approach to Normal and Pathologic Conditions

The external ear (EE) is an osseous-cartilaginous structure that extends from the auricle to the tympanic membrane. It is divided into two parts: the auricle (or pinna) and the external auditory canal (EAC). Given the ease of access to the EE, imaging studies are not always needed to make a diagnosis. However, when lesions block visual access to areas deep to the EE abnormality, complications are suspected, or there is lack of response to treatment, imaging becomes essential. A basic understanding of the embryologic development and knowledge of the anatomy of the auricle and EAC are useful for accurate diagnosis of EE lesions. Congenital, traumatic, inflammatory, neoplastic, and vascular conditions can affect the EE. An overview of the anatomy and embryologic development of the EE is presented, with discussion and illustrations of common and uncommon conditions that affect EE structures and a focus on the CT and MRI features that are of interest to radiologists. CT is usually the first diagnostic modality used to evaluate the EAC and is the superior method for demonstrating bone changes. MRI provides excellent tissue characterization and enables one to better define lesion extension and perineural tumor spread. In addition, a flowchart to facilitate the differential diagnosis of EE abnormalities is provided. Online supplemental material is available for this article. ^©RSNA, 2022.

Transnasal endoscopic surgery of sphenoid meningocele associated with pituitary adenoma. A case report

BACKGROUND

Transsphenoid meningoencephalocele is a congenital anomaly formed by herniation of an ependyma delimited sac through a bony defect into the sphenoid sinus. The sac contains cerebrospinal fluid and neurovascular structures. The prevalence of transsphenoid meningoencephalocele in the adult population is rare. It usually manifests as nasal liquorrhoea.

METHODS AND RESULTS

This case report presents an adult male who underwent surgery due to suspected pituitary macroadenoma. The surgery was performed endoscopically via the transnasal approach with a surprising finding of true transsphenoid meningoencephalocele. Ectopic solid tissue was found in the sphenoid sinus in which pituitary adenoma was histologically confirmed.

CONCLUSION

This paper presents a previously unpublished combination of true transsphenoid meningoencephalocele and pituitary adenoma in an adult individual.

Masses of developmental and genetic origin affecting the paediatric craniofacial skeleton

Although rare, masses and mass-like lesions of developmental and genetic origin may affect the paediatric craniofacial skeleton. They represent a major challenge in clinical practice because they can lead to functional impairment, facial deformation and disfigurement. The most common lesions include fibrous dysplasia, dermoid cysts, vascular malformations and plexiform neurofibromas. Less common lesions include torus mandibularis and torus palatinus, cherubism, nevoid basal cell carcinoma syndrome, meningoencephalocele and nasal sinus tract. This article provides a comprehensive approach for the evaluation of children with masses or mass-like lesions of developmental and genetic origin affecting the craniofacial skeleton. Typical findings are illustrated and the respective roles of computed tomography (CT), cone beam CT (CBCT), magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) sequences and ultrasonography (US) are discussed for the pre-therapeutic assessment, complex treatment planning and post-treatment surveillance. Key imaging findings and characteristic clinical manifestations are reviewed. Pitfalls of image interpretation are addressed and how to avoid them. TEACHING POINTS: • Masses of developmental and genetic origin may severely impair the craniofacial skeleton. • Although rare, these lesions have characteristic imaging features. • CT, MRI and ultrasonography play a key role in their work-up. • Recognition of pivotal imaging pearls and diagnostic pitfalls avoids interpretation errors.

Posttraumatic Temporal Bone Meningocele Presenting as a Cystic Mass in the External Auditory Canal

INTRODUCTION

Temporal bone meningoencephalic herniation may occur in head trauma. It is a rare condition with potentially dangerous complications. Several different routes for temporal bone meningoencephalocele have been proposed.

CLINICAL REPORT

An11-year-old boy with history of head trauma initially presented with a 9-months history of progressive right-sided hearing loss and facial weakness. The other complaint was formation of a cystic mass in the right external auditory canal. The patient underwent surgery via a mini middle cranial fossa craniotomy associated with a transmastoid approach.

CONCLUSION

Although presenting symptoms can be subtle, early suspicion and confirmatory imaging aid in establishing the diagnosis. The combination of computed tomography and magnetic resonance imaging will help in proper preoperative diagnosis. The operation includes transmastoid, middle cranial fossa repair, or combination of both. The multilayer closure of bony defect is very important to avoid cerebrospinal fluid leak. Clinical manifestations, diagnosis, and surgical approaches for posttraumatic meningoencephaloceles arising in the head and neck region are briefly discussed.

Spontaneous Giant Pseudomeningocele in the Middle Cranial Fossa as a Cause of Pulsatile Proptosis

The authors report a case of a 70-year-old man who presented with a long history of left pulsatile proptosis, irritation, and a pressure sensation behind the eye. Initial computed tomography brain demonstrated the presence of a suspected ethmoid sinus mucocele. Endoscopic sinus surgery was performed to drain the mucocele. On cautious opening of the nasal mucosa, cerebrospinal fluid was encountered requiring subsequent repair with local mucosal flap and fat graft. On further magnetic resonance imaging, the lesion was confirmed to be giant pseudomeningocele arising from the sphenoid sinus, with extensive invasion and erosion of the middle cranial fossa including the left lateral orbital wall. Here, the authors report, to the best of their knowledge, the first case of spontaneous giant pseudomeningocele in the middle cranial fossa causing pulsatile proptosis. In examining this case, the authors will also discuss the pathogenesis, diagnosis, and management of giant pseudomeningoceles, especially in the situation of a misdiagnosis.

Endoscopic pedicled nasoseptal flap repair of spontaneous sphenoid sinus cerebrospinal fluid leaks

Spontaneous cerebrospinal fluid (CSF) leaks in the sphenoid sinus are an uncommon but potentially significant condition associated with thin pneumatised bone, obesity and raised intracranial pressure. Despite advances in endoscopic sinus surgery, successful repair remains problematic due to limitations in visualisation, access and management of underlying aetiological factors. Utilisation of vascularised tissue in the primary repair process of sphenoid CSF leaks is yet to be well explored in the literature. In this series, we describe our surgical approach and explore related clinical, pathological and operative factors in three cases of spontaneous sphenoid sinus CSF leaks, successfully repaired on first attempt with the use of a vascularised nasoseptal flap.

Petrous and sphenoid arachnoid cysts: diagnosis and management

BACKGROUND

Intraosseous arachnoid cysts are rare and difficult to diagnose. The purpose of this study was to describe the clinical and radiological semiology of petrous and sphenoid arachnoid cysts and to propose a specific management strategy.

METHODS

This was a retrospective, descriptive study of patients with arachnoid cysts, which utilized CT, MRI, and the patients' medical histories.

RESULTS

Ten patients were included in this study. On CT, the lesions were lytic with bony delineation. On MRI, the lesions exhibited the same signals as cerebrospinal fluid and were not enhanced after contrast. On fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted sequences, the arachnoid cysts' signal disappeared, which is a key feature for eliminating the diagnosis of cholesteatoma. Two patients underwent surgery because of misdiagnosis, either with a meningocele or a cholesteatoma.

CONCLUSION

MRI FLAIR and diffusion-weighted sequences, together with osseous CT scans, help to distinguish arachnoid cysts from meningoceles and avoid unnecessary surgeries with potential complications.

Distant pseudomeningoceles of the ventral skull base: a report of 2 cases

BACKGROUND

The objective of this case series was to report what is to the best of our knowledge the first reports of nasopharyngeal and soft palate pseudomeningoceles tracking submucosally from the sphenoid sinus.

METHODS

Analysis of cases through medical records.

RESULTS

Two cases of middle-aged male patients presented to our tertiary care university teaching hospital for recurrent meningitis and a history of cerebrospinal fluid (CSF) rhinorrhea. Both were found to have pseudomeningoceles distant from the sphenoid sinus. One was tracking to the mucosa of the Eustachian tube, and the other to the dorsum of the soft palate. Both were found to be tracking submucosally from the sphenoid sinus, to the vidian canal, to the lateral nasopharyngeal wall, to their respective locations at the Eustachian tube and dorsum of the soft palate. CSF closure was performed with a transnasal endoscopic repair using the pedicled nasoseptal flap for 1 patient and Alloderm for the other, both with successful cessation of CSF rhinorrhea.

CONCLUSION

We present these cases of distant spontaneous CSF leaks. We review the literature and discuss case management.

Unusual presentation of an asymptomatic pseudomeningocele within the sphenoid sinus

OBJECTIVE

We report the rare case of a 55-year-old woman with an asymptomatic left sphenoid sinus pseudomeningocele mimicking a mucocele.

CASE REPORT

A 55-year-old woman was found to have an incidental mass in the left sphenoid sinus on computed tomography. Magnetic resonance imaging confirmed the presence of a mucocele. A left endoscopic sphenoidotomy was performed to drain the mucocele. Despite an anatomical puncture through a stenosed sphenoid ostium, alarmingly, the opening leaked cerebrospinal fluid. A dehiscent lateral wall was identified with a dural opening communicating with the sphenoid sinus. This was immediately repaired with a free nasal septal mucosal graft. Six months post-operatively, the patient remained free from cerebrospinal fluid leakage.

CONCLUSION

Pseudomeningoceles are extremely rare in the absence of trauma or iatrogenic injury. Surgeons should be alert to their presence as they can mimic a unilateral mucocele or nasal polyp. Endoscopic management lends itself to a single-stage repair.

Lesions of the skull base: imaging for diagnosis and treatment

This article provides a summary of how to approach the imaging analysis of lesions of the anterior, central, and posterior skull base. The primary focus is tumors and tumor-mimickers, and representative examples are shown to differentiate the features of lesions that can occur in the same location.

Transethmoidal meningocele: an unusual complication of intracranial neoplasm

Cranial meningoceles/encephaloceles are congenital malformations characterised by protrusion of the meninges and/or brain parenchyma because of a skull defect. Meningoceles secondary to an intracranial neoplasm have not been reported in the published literature. We report a unique case of a 42-year-old man who presented with a sudden onset of altered sensorium. Transethmoidal meningocele secondary to an intraventricular epidermoid cyst was detected on imaging.