a small intro to the big topic of Glomus in Otology

1. Glomus- an intro

2. Intro
• Valentin 1840
▫ Swellings along tympanic nerve
• Guild 1941
▫ Classical description of “glomus jugularis”

3. • Glomus is a collection of ganglionic tissue within
the Temporal bone in close relation with jugular
bulb.
• Arising from paraganglionic glomic tissue ,
distributed along parasympathetic nerves.
• Composed of cells that are sensitive changes in
arterial oxygen, CO2 & pH.

4. • Misnomer
▫ Glomus means a small circumscribed histological
structure in which arterioles connect directly with
veins
• Synonyms
▫ Paraganglioma
▫ Chemodectoma
▫ Tympanic body tumors
▫ Receptoma
▫ Non-chromaffin paraganglioma
▫ Glomerocytoma

5. • Histologically BENIGN
• Slow growing
• Clinically morbid
• Internal Carotid Artery
• Hereditary
• Female 4-6X more
• Infants to older age group , commonly in 50s
&60s

6. • Neural crest origin closely associated
anatomically with autonomic ganglia
• Diffuse NeuroEndocrine System
▫ ‘chief cells’
▫ 40 different types of other cells
▫ APUD amine precursor uptake & decarboxylation
 Necessary step in biosynthesis of neurotransmitters
 Neuropeptides, catecholamines,neurohormaones ,
neurotransmitters, hormones and parahormones
 Functional tumors- 1-3%

7. • Paraganglioma of temporal bone are located
along Jacobson’s nerve and are symmetric
• Innervated by cranial nerves IX &X and supplied
Ascending Pharyngeal Artery
• Multicentric, Bilateral
• Nonfamilial – 10% multicentric
• Familial – 25-50% multicentric

8. • From middle ear promontory- GLOMUS
TYMPANICUM
• From jugular foramen – GLOMUS JUGULARE
• From perineurium of vagus extending towards
jugular foramen- GLOMUS VAGALE

9. • In Temporal bone Glomus bodies are in close
relation to
▫ Tympanic branch of Glossopharyngeal nerve
▫ Auricular branch of vagus nerve
▫ Adventitita of jugular bulb
▫ Promontory

10. Relevant Anatomy
• Jugular Bulb
• Middle ear cavity
• Vagus nerve
• Carotid body
• Jugular foramen

13. Jugular foramen
• 2nd largest skull base foramen
• Asymmetrical
• Vital structures- vascular and neural
• Lateral part sigmoid shaped tunnel
• Medial part canal in cephalocaudal direction

14. • Located behind carotid canal
• Bounded
▫ anteriorly by petrous portion of temporal bone
▫ Posteriorly by occipital bone

15. • Delineated by jugular spine
• Smaller anteromedial ‘pars nervosa’
• Larger posterolateral ‘ pars vascularis’

16. • Is large elongated with long axis forwards and medially
• Posterior end of hollowed to form JUGULAR FOSSA
lodging the superior bulb of internal jugular vein
• Fossa large on right
• Lateral wall pierced by minute canal, mastoid
canaliculus
• Medial end possess jugular notch, apex of which
opening leading to cochlear canaliculus
• Tympanic canaliculus opens on or near thin edge of bone
between jugular fossa and lower end of carotid canal

17. Structures passing
• Anterior part
▫ Inferior petrosal sinus
▫ Meningeal branch of ascending pharyngeal artery
• Middle part
▫ IX,X & XI cranial verves
• Posterior part
▫ Internal jugular vein
▫ Meningeal branch of Occipital artery
Inferior ganglion of glossopharyngeal nerve is lodged in
the glossopharyngeal notch near medial end

18. Infra Temporal Fossa
• The infratemporal fossa lies below the middle
cranial fossa, between the ramus of the mandible
and the lateral wall of the pharynx
• The 'roof' is the infratemporal area of the skull
base, which comprises the greater wing of the
sphenoid with a small triangular contribution
posteriorly from the squamous temporal bone.
• .

19. • It has
▫ no anatomical floor and continues down into the neck.
▫ Anteriorly lies the posterior wall of the maxilla with the
pterygomaxillary and inferior orbital fissures;
• Posteriorly, it is bounded by the carotid sheath and styloid
apparatus.
• The fossa is limited
▫ medially by the medial pterygoid muscle and interpterygoid
fascia, and
▫ laterally by the mandible.
• The contents of the fossa are the
▫ lateral and medial pterygoid muscles, the maxillary artery and its
branches,
▫ the pterygoid venous plexus and maxillary veins and the
▫ branches of the mandibular nerve

22. Spread
• Growth is by direct extension along lines of least
resistance or by ischemic necrosis
• Multiple pathways lead intracranially
• Incidence of malignant transformation 4%

24. • Glomus jugulare, tend to spread around the
venous sinuses surrounding the jugular bulb.
• Sometimes collectively referred to as the
“danger zone,” the venous sinuses most
commonly involved include
▫ the inferior petrosal sinus,
▫ internal jugular vein, and
▫ the sigmoid sinus

25. • Extend toward and beyond the protympanum,
hypotympanum, mesotympanum, or intracranial
cavity
• From protympanum –
▫ peritubal cell tracts toward the petrous apex,
▫ the carotid canal toward the middle cranial fossa,
or
▫ the Eustachian tube toward the nasopharynx

26. • From hypotympanum - luminal invasion of
either
▫ the sigmoid sinus or
▫ internal jugular vein or
▫ spread toward the inferior petrosal sinus or
▫ neural foramina at the skull base
▫ Carotid sheath lends access to neck

27. • From mesotympanum -similar spread as
cholesteatoma (antrum and epitympanum or
the facial recess, sinus tympani, or mastoid air
cells)
• Laterally through the tympanic membrane--
external auditory canal,
• Medially through the round window and erode
the cochlea and internal auditory canal