Neurosurgery notes/Tumours/Cranial and paraspinal nerve tumours/Paraganglioma (Glomus tumour)/Glomus tumours

Glomus tumours

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Paraganglioma (Glomus tumour)

Localisation subdivision

  • Temporal bone paragangliomas (TBP)
    • Tympanomastoid paragangliomas (TMP)
      • Aka Glomus tympanicum tumour
      • Arise within the inferior tympanic or mastoid canaliculi
      • Most common neoplasm of the middle ear.
      • Vascular supply
        • Auricular artery
    • Tympanojugular paragangliomas (TJP)
      • Aka Glomus jugulare
      • Vascular supply
        • ECA:
          • Inferior tympanic branch of ascending pharyngeal artery
          • Branches of posterior auricular, occipital,
          • Internal maxillary
        • Additional feeders from petrous portion of the ICA
      • Arise within paraganglia of the adventitia of the jugular bulb (JB)
        • In the jugular foramen at the junction of the sigmoid sinus and jugular vein
      • May have finger-like extension into the jugular vein (which may embolize during resection)
  • Neck paragangliomas (vagal and carotid body paragangliomas)

Numbers

  • Rare
  • 2nd commonest tumour to invade temporal bone after Vestibular schwannoma
  • 0.6% of all head and neck tumours
  • Female: male ratio is 6:1.
  • Bilateral occurrence is almost non-existent
  • Together with pheochromocytomas they have an incidence of 3 cases per million population

Origin

  • Presumably arise from microscopic paraganglia within the temporal bone

Pathology

  • Histologically indistinguishable from carotid body tumors.
  • May invade locally, both through temporal bone destruction and especially along pre-existing pathways (along vessels, eustachian tube, jugular vein, carotid artery).
  • Intradural extension is rare.
  • Malignancy, although rare, may occur.
  • These tumors rarely metastasize.

Modified Fisch Classification of temporal bone paragangliomas (TBPs)

  • Tympanomastoid paragangliomas (TMPs)
    • Class A - Tumors confined to the middle ear
      • A1 - Tumor margins clearly visible on otoscopic examination
      • A2 - Tumor margins not visible on otoscopy. Tumors may extend anteriorly to the Eustachian tube and/or to the posterior mesotympanum
        • Tympanic paraganglioma (Fisch class A):
          • Axial CT scan of a tympanic paraganglioma (bone window) on the right promontory.
          • Note the absence of any bony erosion.
        A close-up of a brain scan AI-generated content may be incorrect.
    • Class B - Tumors confined to the tympanomastoid cavity without destruction of bone in the infralabyrinthine compartment of the temporal bone
      • B1 - Tumors involving the middle ear with extension to the hypotympanum
      • B2 - Tumors involving the middle ear with extension to the hypotympanum and the mastoid
      • B3 - Tumors confined to the tympanomastoid compartment with erosion of the carotid canal
        • Tympanic paraganglioma (Fisch class B):
          • The axial CT scan reveals a left-sided tympanic paraganglioma surrounding and partially destroying the ossicles.
          • The malleus and stapes could not be discriminated.
          • The tumor had also invaded the hypotympanon.
          • There was no destruction of the bone wall to the jugular bulb.
        A close-up of a brain scan AI-generated content may be incorrect.
  • Tympanojugular paragangliomas (TJPs)
    • Class C - Tumors extending beyond the tympanomastoid cavity, destroying bone of the infralabyrinthine and apical compartment of the temporal bone and involving the carotid canal
      • C1 - Tumors with limited involvement of the vertical portion of the carotid canal
      • C2 - Tumors invading the vertical portion of the carotid canal
      • C3 - Tumors with invasion of the horizontal portion of the carotid canal
      • C4 - Tumors reaching the anterior foramen lacerum
        • Jugular paraganglioma (Fisch class C):
          • Axial CT scan showing a left-sided jugular paraganglioma.
          • Note the bone destruction between the jugular bulb and the soft tissue tumor in the hypotympanon.
        A close-up of a brain scan AI-generated content may be incorrect.
    • Class D - Tumors with intracranial extension
      • De1 - Tumors up to 2 cm dural displacement
      • De2 - Tumors with more than 2 cm dural displacement
      • Di1 - Tumors up to 2 cm intradural extension
      • Di2 - Tumors with more than 2 cm intradural extension
      • Di3 - Tumors with inoperable intradural extension
        • Tympanic paraganglioma (Fisch class D):
          • Time-resolved contrast-enhanced MR-angiography (upper row) depicts an early venous drainage attributed to arterio-venous fistulas within this tympanic paraganglioma (solid arrows).
          • Coronal CT (lower row left) of the petrous bone shows a soft tissue tumor with encasement of the ossicles within the whole tympanon, and destruction of the tegmen tympani.
          • Coronal T2-weighted and contrast enhanced T1-weighted images show a small, but distinct, intracranial but extradural tumor growth on the lateral skull base (dotted arrows, lower row).
        A close-up of a brain scan AI-generated content may be incorrect.
    • Class V - Tumors involving the VA
      • Ve - Tumors involving the extradural VA
      • Vi - Tumors involving the intradural VA

Clinical presentation

Symptom
Anatomical structure involved
Deafness
Middle ear/Cochlea
Dizziness/Vertigo
Labyrinth/CPA—cranial nerve VIII
Dysphonia
Jugular foramen—cranial nerve X
Dysphagia
Jugular foramen—cranial nerves IX/X
Facial weakness
Petrous bone/CPA—cranial nerve VII
Facial numbness
Petrous apex/CPA—cranial nerve V
Double vision
Petrous apex/CPA—cranial nerve VI
Headache
Brainstem/fourth ventricle—hydrocephalus
Tongue wasting
Hypoglossal canal—cranial nerve XII
  • Given the slow growth and the nonspecific nature of the symptoms, patients present with an average of 2–3 years delay after the onset of the symptoms.
  • 36% of all jugulotympanic paragangliomas extend into the cranial cavity
  • Brown’s sign,
    • Blanching of the middle ear component,
    • Present in 20% of the cases
    • Otoscopy alone is not reliable to assess the extent, most significantly related to the degree of hypotympanic extension
  • Rising sun sign:
    • TBPs invading the tympanic bone from the jugular fossa
        • Paragangliomas can also extend through the tympanic membrane and be confused with an inflammatory polyp.
        notion image
    • Otorrhagia can be a significant clinical symptom.
  • 90% pulsatile tinnitus
    • Hyper Vascular Lesion
    • A pulsatile middle ear mass is pathognomonic of a temporal bone paraganglioma
  • 80% hearing loss (local invasion)
    • Conductive because the tumour compresses or erodes the ossicular chain, or due to effusion.
    • Later on can become sensorineural hearing loss when inner ear is invaded (might have concomitant vestibular symptoms.
  • 10% otalgia and aural fullness
  • Lower cranial nerve dysfunction
    • Due to invasion of the medial wall of the jugular fossa.
      • A jugular fossa pathology is present if pt presents with isolated or multiple LCN palsies.
      • Complete cranial nerves examination, including palpation of the neck and upper aero-digestive tract endoscopy, is an integral part of the examination for TBPs.
    • 10% of the cases, cranial nerve palsies can be silent.
      • Due to
        • Slow progression
        • Gradual compensation from the contralateral nerves.
    • Palsies of CN9/10
      • 35–40%
      • Vocal fold paralysis → change in voice
        • Most common
      • Palatal asymmetry strongly suggests a skull base pathology involving the glossopharyngeal or vagus nerves.
    • Palsies of CN11/12
      • 21–30%
    • CN7 palsies
      • 10–39%
      • Earliest affected by Tympanojugular paragangliomas (TJP)
    • Jugular Foramen Syndromes
        • Vernet
          • CN IX – CN XI
        • Collet-Sicard
          • CN IX – CN XII
        • Villaret
          • CN IX – CN XII + Horner’s Syndrome
        x Vernet Xll Collet- Sicard hypogl canal Jackson sympathetics Villare I jugular foramen Schmidt to arynx to Ian
        Tymp. rit car: Å. ong• Up.,LarypÅ xt*éår. A. Cl MetfrBr: nt ju*v. ran . roc.
  • Hydrocephalus
  • Horner’s syndrome
  • Secretory properties
    • These tumors usually possess secretory granules (even the functionally inactive tumors) and may actively secrete catecholamines (similar to pheochromocytomas, occur in only 1–4% of GJT).
    • Secrete norepinephrine and not epinephrine
      • Glomus tumors lack the methyltransferase needed to convert this to epinephrine.
    • May produce carcinoid-like syndrome
      • By secreting
        • Serotonin and kallikrein
      • Bronchoconstriction, abdominal pain and explosive diarrhea, violent H/A, cutaneous flushing, hypertension, hepatomegaly and hyperglycemia
    • During surgical manipulation, these tumors may also release histamine and bradykinin, causing hypotension and bronchoconstriction
    • A secreting tumour would need to be managed with α blockers 2 weeks before surgery and with a β blocker the day before surgery to prevent a hypertension crisis

Investigation

Hearing

  • Audiometry

Laryngoscopy

  • Vocal cords

Endocrinology

  • 24 hours catecholamines
    • Glomus tumor check for metanephrine → HTN give alpha blockers and not beta blockers due to widespread vasospasm

Imaging

General

  • Since TJPs cannot be biopsied due to their vascularity, the diagnosis is based solely on radiology.

High-resolution CT

  • Bone erosion
    • “Moth eaten” appearance
    • The margins of the jugular fossa may be irregular and expanded, with evidence of erosion of the caroticojugular crest or jugular spine.
    • In advanced cases, the entire jugular foramen may be destroyed.
    • Differentiate TMP VS TJP
      • If the jugular foramen is found to be by and large free of tumor or anatomical distortion, it is most likely to be a TMP
  • CT+ C
    • Enhance vividly (as do paragangliomas elsewhere).

MRI

  • Advantage
    • Can be done then to distinguish TMP VS TJP
      • MRI is very useful in mapping TJP
    • It provides information about the extent of the tumor, both into the neck and intracranially
    • Dural invasion is difficult to detect due to the fact that the dura is often pushed medially rather truly infiltrated.
    • MRI also gives information regarding invasion into the marrow spaces of the skull base, with obliteration of the normal fatty signal.
      • TJPs
        • Incidence of intracranial extension 60–75%
        • Incidence of intradural involvement 30%
  • T1
    • Intermediate intensity
  • T2
    • Hyperintense
    • “Salt and pepper” pattern
      • Can be seen in lesions >2 cm
      • Due to a mixture of
        • Area of hyperintensity = slow flow within the tumor
        • Ares of hypointensity = flow voids
  • Dual T2 fast spin echo sequences,
  • Non-contrast and contrast time of flight sequences
  • Contrast magnetic resonance angiography (MRA)
  • MRV
 
(d)

Angiography

  • Characteristic blush and rapid venous diffusion.
  • A 4-vessel angiography is reserved for difficult cases with ICA and VA involvement.
  • Demonstrates the
    • Vascular supply of the tumor,
    • Degree of ICA involvement
    • Contralateral cerebral blood flow
    • Venous drainage
    • Aids in pre-operative embolization in case of surgery.
A close-up of an angiogram AI-generated content may be incorrect.

Differential diagnosis

  • Cerebellopontine angle (CPA) lesions
    • The major differential is neurilemmomas (vestibular schwannomas), both enhance on CT.
    • A cystic component and extrinsic compression of the jugular bulb are characteristic of neurilemmomas.
    • Angiography will differentiate difficult cases