Spontaneous encephaloceles of the temporal lobe

Abstract

<jats:p>Encephaloceles are pathological herniations of brain parenchyma through congenital or acquired osseus-dural defects of the skull base or cranial vault. Although encephaloceles are known as rare conditions, several surgical reports and clinical series focusing on spontaneous encephaloceles of the temporal lobe may be found in the otological, maxillofacial, radiological, and neurosurgical literature. A variety of symptoms such as occult or symptomatic CSF fistulas, recurrent meningitis, middle ear effusions or infections, conductive hearing loss, and medically intractable epilepsy have been described in patients harboring spontaneous encephaloceles of middle cranial fossa origin. Both open procedures and endoscopic techniques have been advocated for the treatment of such conditions. The authors discuss the pathogenesis, diagnostic assessment, and therapeutic management of spontaneous temporal lobe encephaloceles. Although diagnosis and treatment may differ on a case-by-case basis, review of the available literature suggests that spontaneous encephaloceles of middle cranial fossa origin are a more common pathology than previously believed. In particular, spontaneous cases of posteroinferior encephaloceles involving the tegmen tympani and the middle ear have been very well described in the medical literature.</jats:p>

Brain Herniations into the Dural Venous Sinuses or Calvarium: MRI of a Recently Recognized Entity

“…Temporal encephaloceles are parenchymal herniations through the dura mater and bone and involve the middle cranial fossa or lateral temporal cranium. Their major symptoms are epilepsy or disturbances such as hearing loss, otorrhea, Although the exact pathogenesis of spontaneous temporal encephaloceles is unclear, progressive dural and osseous thinning secondary to elevated CSF pressure, osseous variations, inflammation, aging, and erosive arachnoid granulations are among the etiologies thought to be responsible 2,10,11 . Coban et al thought that their occult temporal encephalocele may have resulted from intracranial pressure changes 2 .…”

Closed Meningo(encephalo)cele: A New Feature in Hunter Syndrome

“…Of note, these abnormalities have been found in sites most frequently involved in skull defects in the general population. The complexity of the bone maturation process of these regions likely contributes to their pathogenesis (the middle cranial fossa presents with at least 19 ossification nuclei, 14 while the thin lamina cribrosa represents a weak area of the skull due to the several holes for the extraintracranial passage of the phila olfactoria).…”

“…Meningoencephaloceles are malformations characterized by protrusion of meninges and/or brain tissue due to a skull defect that may be the result of various acquired processes including trauma, surgery, infection, and neoplasm, or of a primitive defect of neural tube closure. [13][14][15] To our knowledge, such a condition has never been previously described in Hunter syndrome; therefore, all the MR imaging examinations were reevaluated to define the frequency of focal parenchymal and/or meningeal herniation in our cohort and the possible correlation with clinical phenotype or other neuroradiologic abnormalities.…”

Assessment and Treatment of Spontaneous Temporal Bone Meningoencephalocele for Hearing Gain

“…Despite various names according to the content of the herniated tissue (e.g., meningocele versus meningoencephalocele), the term meningoencephalocele may be used broadly in reference to the temporal bone [1]. Meningoencephaloceles can be classified into cranial and basal varieties; cranial meningoencephaloceles typically involve the occipital and frontonasal regions, while lateral temporal lobe meningoencephaloceles and midline temporal lobe meningoencephaloceles present as masses in the sphenoid sinus [3][4][5][6]. Our patient presented a lateral temporal lobe meningoencephalocele with a small spontaneous defect of the tegmen tympani.…”

“…Trauma, surgery, and malignancy most commonly produce these defects, but the spontaneous development of these complications without identifiable causes is less common [2]. The defects are conventionally repaired through a limited subtemporal craniotomy with elevation of the temporal lobe, or through a combined transmastoid and Middle Cranial Fossa (MCF) approach [3][4][5][6]. A more conservative intervention through the mastoid alone has been proposed by some authors in order to reduce the morbidity of the procedure.…”