Glomus tumors originate from paraganglionic tissue located in the temporal bone near the jugular foramen and associated nerves. They can grow slowly and extend along pathways in the skull base, spreading to nearby structures like the sigmoid sinus, internal jugular vein, and inferior petrosal sinus. While typically benign, glomus tumors are clinically significant due to their location and potential for local invasion or malignant transformation in rare cases.

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