Tag Archives: Extraaxial

Skull Base Syndromes

Subtypes: Jugular foramen syndrome= Vernet’s syndrome Collet-Sicard syndrome= Posterior lacerocondylar area syndrome= intercondylar space syndrome Retropharyngeal space syndrome= Villaret’s syndrome Hypoglossal canal syndrome, Foramen magnum syndrome, Carotid canal syndrome Clinical features: Features depend on involved nerves: Symptions: Choking, dysphagia, speech changes, auditor canal pain, headache Features by nerve: IX: loss of gag reflex, sensation of … Continue reading Skull Base Syndromes

Epidural Abscess (intracranial or spinal)

Diagnosis: Imaging (MRI with and without contrast) plus biopsy for confirmation Pathology: Biopsy: Necrosis with inflammation (neutrophils & later macrophages & lymphocytes), rim of fibrosis (if absent this is cerebritis) Surrounding gliosis Clinical features: Intracranial: focal neurological deficit Spinal: transverse myelopathy and a flexed posture resisting extension, back pain with fever. Investigations to consider: FBC, … Continue reading Epidural Abscess (intracranial or spinal)

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS)

Diagnosis: Clinical features, MRI and occasionally biopsy Clinical features: Episodic diplopia or facial paresthesias with subsequent brainstem and occasionally myelopathic symptoms and had a favourable initial response to high dose glucocorticosteroids Findings on Investigations: +MRI: Symmetric curvilinear gadolinium enhancement peppering the pons and extending variably into the medulla, brachium pontis, cerebellum, midbrain and occasionally spinal … Continue reading Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS)

Idiopathic Hypertrophic Cranial Pachymeningitis

Diagnosis: Rare, A diagnosis by exclusion Note: Pachymeningitis is a radiologic pattern Clinical features: Severe headache, cranial nerve palsies, ataxia, loss of vision (optic nerve involvement) Pathology: Biopsy: Meningeal Polymorphonuclear infiltration Findings on Investigations: MRI: T1 +contrast: enhancement of the meninges without enhancement of the sulci. Involves the tentorium, falx, calvarium T2: hypointense dura Investigations … Continue reading Idiopathic Hypertrophic Cranial Pachymeningitis

Lumbar spinal stenosis

Synonyms: formerly ‘pseudoclaudication’ Diagnosis: Any developmental or acquired narrowing of the spinal canal (spinal canal stenosis), nerve root canal, or intervertebral foramina a.k.a. neural foramina, that results in compression of neural elements Clinical features: (must be present) Pain & numbness in lower back, buttocks & legs on walking or lumbar extension History: Painful gait, Absence … Continue reading Lumbar spinal stenosis

Spondylolisthesis and Spondylolysis

Diagnosis: These are imaging findings. Whether they are the cause of deficits requires clinical correlation plus electrophysiology as necessary Spondylolisthesis: Slipping of one vertebra upon another Spondylolysis: a bony defect (fracture) in the pars interarticularis (connects the pedicle and lamina on axial plane, connects superior and inferior articular processes of the facet joints on sagittal … Continue reading Spondylolisthesis and Spondylolysis

Cervical Spondylosis

Note this can cause myelopathy and radiculopathy Synonyms: a.k.a. osteoarthropathy of the cervical spine Diagnosis: Imaging confirms the presence of degenerative changes but doesn’t confirm that it is the cause of radiculopathy or myelopathy X-ray spine: Osteophytes, narrowed disk spaces, narrowed framina This confirms the presence of degenerative changes but doesn’t confirm that it is … Continue reading Cervical Spondylosis

Perineural Cyst

Synonyms: a.k.a. Tarlov cyst Diagnosis: MRI: Sacral, bilateral, cyst along nerve roots Follows CSF signal on all sequences Pathology: Histology: Not a true cyst, but separation of the epineurium from the perineurium Collagenous tissue, nerve fascicles.  

Enterogenous Cyst

Synonyms: Endodermal cyst, Diagnosis: Usually by MRI. Pathology is confirmatory. Findings on investigations: MRI: Anterior to the cord Associated with vertebral abnormalities lower than the lesion. Associated with respiratory tract abnormalities if bronchogenic cyst and GIT abnormalities if neuroenteric. Pathology: Histology: Well differentiated columnar epithelium, ciliated or nonciliated +/-mucus +/-goblet cells. PAS positive membrane Rarely … Continue reading Enterogenous Cyst

Dermoid Cyst

Diagnosis: Usually by MRI imaging, but pathology is confirmatory Findings on investigations: MRI: Near fontanelle, fourth ventricle, Heterogenous signal Pathology: Histology: Cyst lined by epithelium, adnexial/dermal tissue (hair & sweat glands) i.e. both layers of the skin Cyst filled with keratinised material Treatment: Surgical resection Related articles: Epidermoid cyst,

Epidermoid Cyst

Diagnosis: Usually by MRI imaging Findings on investigations: CT: low density, irregularly enhancing rim MRI: Cerebellopontine angle, suprasellar, infrasellar variable signal (dependent on lipid content) Pathology: Histology: Cyst lined by epithelium, keratinisation, no adnexial/dermal tissue (hair & sweat glands) i.e. only top layers of the skin Cyst filled with keratinised material Treatment: Surgical resection  

Arachnoid Cyst

Diagnosis: Usually made by MRI imaging Findings on investigations: MRI: Extraaxial. Supratentorial or infratentorial. Supratentorial; middle cranial fossa & third ventricle, perisellar cistern, along the convexities. Infratentorial; retrocerebellar cistern, cerebellopontine angle cistern, quadrigeminal cistern. Rarely intraventricularly. Mild mass effect. isointense with CSF on T1 & T2. Nonenhancing CT: isodense with CSF Intrathecal contrast: initially nonenhancing, … Continue reading Arachnoid Cyst

Meningeal cyst

Diagnosis: Usually the diagnosis can be made by MRI imaging Pathology: Histology: Actually a diverticulum. Thick dura like collagen layer and inner membrane of arachnoid.


Synonyms and subtypes: a.k.a. carotid body tumor, glomus jugulare tumor, glomus tympanicum Diagnosis: Suggested by MRI and confirmed by pathology (brain biopsy/resection) Findings on Investigations: MRI: Neck mass (carotid body tumor, glomus jugulare tumor), middle ear canal mass (glomus tympanicum) Filum terminale Enhancing lesion MRA: blood supply can be assessed. Catheter Angiogram: To assess vascular … Continue reading Paraganglioma


Diagnosis: Suggested by MRI and confirmed by pathology (brain biopsy/resection) Clinical features: Bitemporal hemianopia (chiasm lesion), homonymous hemianopia (optic radiation, pregeniculate) Findings on Investigations: MRI: Clivus or sacrum Optic chiasm compression Pathology: Histology: Lobulated, fibrovascular septa. Epitheloid cells in chords/rows in mucoid stroma. Physaliphorus Cells (bubble cells)= central nuclei, bubble like vacuolated cytoplasm. Focal cartilage … Continue reading Chordoma


Synonyms: Vestibular Schwannoma a.k.a. acoustic neuroma (formerly neurilemmoma) Diagnosis: Suggested by MRI and confirmed by pathology (brain biopsy/resection) Pathology: Histology: Antoni A pattern: cellular, Spindle cells. Verocay bodies (palisading). Antoni B pattern: less cellular, round nuclei, vacuolated cells, microcysts Immunohistochemsitry: Positive S100 Findings on Investigations: MRI: VIII nerve. Extends into the internal auditory canal IAC. … Continue reading Schwannoma


Diagnosis: Suggested by MRI and confirmed by pathology (brain biopsy/resection) Findings on Investigations: CT: hyperdense, uncommonly calcify, MRI: Extraaxial, parasagittal dura >convexities >sphenoid wing >cerebellopontine angle cistern >olfactory groove >plantum sphenoidale. May encase arteries. May invade bone (hyperostotic or osteolytic). T1: hypointense, enhancement of lesion & dural tail. Vascular flow voids may occur. T2: hypointense, … Continue reading Meningioma

Spinal epidural venous engorgement of pregnancy

Diagnosis: Clinical: Acute spastic monoplegia or paraplegia MRI: vascular congestion (prominent paravertebral & epidural blood vessels), T2 high signal in cord. Compression of IVC by uterus. Resolution of findings after deliver. Related articles: Myelopathy,

Subarachnoid Hemorrhage

Synonyms: Subarachnoid haemorrhage Diagnosis: Findings on Investigations: Diagnosis is established by neuroimaging (CT or MRI) or by lumbar puncture Non-contrast CT: Demonstrates subarachnoid hemorrhage in the acute phase. May be negative, but is positive in the majority of cases. If CT is negative LP is indicated. Blood in CSF spaces: sulci & cisterns. May also … Continue reading Subarachnoid Hemorrhage

Fungal Meningitis

There are various fungi that may cause meningitis. The manifestations vary by causative organism and host immune status. Some organisms are more common in certain geographical locations. Patients may present acutely with headache and encephalopathy or may have a much more indolent course.     Cryptococcal meningitis: Synonyms: Cryptococcosis (Cryptococcus neoformans) Diagnosis: Clinical findings plus … Continue reading Fungal Meningitis

Tuberculous Meningitis

Synonyms: Mycobacterium tuberculosis meningitis, TB meningitis, tuberculoma, tuberculous meningovasculitis Diagnosis: Clinical features plus confirmatory CSF analysis or TB studies Findings in Investigations: Findings remain after 10 days treatment White cell count: moderately high, Usually <500/microL, (100-300/mm3) Mainly lymphocytes Protein: High, >0.8g/L Glucose: Low ,<2.2 mmol/l Or atypically: Neutrophilia if early, normal protein, normal glucose Eosinophilia … Continue reading Tuberculous Meningitis

Viral Meningitis

Diagnosis: Clinical features plus confirmation by CSF analysis & isolation of the virus or PCR or antibody tests Findings on Investigations: CSF analysis: Early LP may show: Increased neutrophils, Glucose normal Later: White cell counts: moderately high, <1000/mL (usually 25-500/microL) Lymphocytes or monocytes RCC: raised in HSV encephalitis Glucose normal Protein: Usually normal Or slightly … Continue reading Viral Meningitis

Bacterial Meningitis

Diagnosis: Clinical features plus confirmation by CSF analysis Findings in Bacterial meningitis: High opening pressure >180 mmH2O, turbid/purulent appearance White cell count: high, 10-10,000/microL Mainly neutrophils (usually >100), but monocytes are suggestive of Listeria monocytogenes Protein: High, >0.45 g/L (>45 mg/dL) Glucose: low, <0.4 of serum (roughly <1/2 serum), or <2.2 mmol/L (<40 mg/dL) Borrelia … Continue reading Bacterial Meningitis