June 14, 2023

EDUCATIONAL PEARL

Glomus Tympanicum (Paraganglioma): Benign tumor of chemoreceptive cells

Notable Presenting Symptoms:
- Pulsatile tinnitus (most common presentation),
- Hearing loss
- CN palsies
- Red-purple middle ear mass (“setting sun” sign)
- Brown’s sign (blanching TM with positive pressure)
- Aquino’s sign (pulsation of paraganglioma decreases with carotid compression)
Epidemiology:
- Most common benign tumor of temporal bone in adults
- 10% multiple; <5% malignant
- 1-3% associated with catecholamine secretion
- 20% family history associated with succinate dehydrogenase mutation
- F>M
Pathophysiology:
- Paraganglion cells that are neural crest in origin
- Types of paragangliomas include:
  - Glomus Tympanicum: Grows near promontory along course of Jacobson’s nerve (tympanic branch of CN IX)
  - Glomus Jugulare: Grows near jugular foramen (the adventitia of bulb); primarily supplied by ascending pharyngeal artery
  - Glomus Caroticum: Grows in carotid body; most common H&N type
  - Glomus Vagale: Grows around vagus nerve at skull base
- Glomus Tympanicum Classification (Glasscock-Jackson):
  - Type I: Small mass limited to promontory
  - Type II: Tumor completely filling middle ear
  - Type III: Within middle ear with mastoid extension
  - Type IV: Within middle ear and mastoid with extension into external auditory canal
Diagnosis:
- Otoscopy/Neuro Exam
- Temporal bone CT with contrast (glomus tympanicum without erosion of bone over jugular bulb)
- MRI/MRA (“salt and pepper lesion” on T2)
- Angiography
- Audiogram
- 24-hr urine catecholamines if suspect secretory tumor
Treatment:
- Surgical resection (transcanal versus extended facial recess approach) with consideration of pre-op embolization.
- Radiosurgery used primarily for glomus jugulare.

Carlson ML, Sweeney AD, Pelosi S, Wanna GB, Glasscock ME 3rd, Haynes DS. Glomus tympanicum: a review of 115 cases over 4 decades. Otolaryngol Head Neck Surg. 2015 Jan;152(1):136-42.