Paragangliomas

Paragangliomas: Intro & Types - Glomus Group Hug

• Neuroendocrine tumors from extra-adrenal paraganglia (neural crest origin).
• A.k.a. chemodectomas, glomus tumors.
• Slow-growing; ~10% malignant potential.
• Often linked to succinate dehydrogenase (SDHx) gene mutations (📌 PGL syndromes).

Common Head & Neck (H&N) Paragangliomas:

Paragangliomas: Clinical & Dx - Symptom Spotting Secrets

• Clinical Presentation (Varies by Site):

  • Carotid Body Tumor (CBT): Pulsatile lateral neck mass. 📌 Fontaine's sign (mobile laterally, not vertically). Bruit. Late CN IX-XII palsies.
  • Glomus Jugulare: 📌 Pulsatile tinnitus, conductive hearing loss. CN IX-XII palsies (Vernet's). Aquino's sign, Brown's sign (TM mass changes with pressure).
  • Glomus Tympanicum: Pulsatile tinnitus, conductive hearing loss. Reddish retrotympanic mass ("Rising sun" sign).
  • Glomus Vagale: Hoarseness (CN X), dysphagia. Neck mass, posterior to mandible.

• Diagnostic Workup:

  • Audiometry: Conductive hearing loss.
  • Imaging is Key:

    • CT: Shows bony erosion (📌 Phelps' sign - jugular spine erosion).

    • MRI: "Salt & pepper" appearance on T1WI+C (flow voids & slow flow).

    • Angiography (DSA): "Lyre sign" (CBT), for pre-op embolization.

  • Biochemical: 24-hr urine VMA/metanephrines (if functional, ~1-3% H&N).
  • ⚠️ Biopsy: Contraindicated pre-op (high bleeding risk).

⭐ "Salt & pepper" MRI (T1WI+C) is classic: flow voids (pepper) & slow flow/hemorrhage (salt).

• Diagnostic Flow:

Paragangliomas: Management - Tumor Takedown Tactics

⭐ For functional paragangliomas, pre-operative alpha-blockade (e.g., phenoxybenzamine) followed by beta-blockade is crucial to prevent intraoperative hypertensive crisis.

• Overall Strategy: Multidisciplinary approach; goals include complete tumor excision, preservation of neurovascular structures, and minimizing morbidity.

• Medical Management (Functional Tumors):

  • Pre-operative α-blockade (e.g., phenoxybenzamine) 10-14 days prior.
  • Follow with β-blockade (e.g., propranolol) if tachycardia develops (NEVER before α-blockade).

• Surgical Resection:

  • Primary treatment for most, especially symptomatic or growing tumors.
  • Pre-operative embolization (24-48h prior) for large/vascular tumors (e.g., glomus vagale, jugulare) to ↓ intraoperative blood loss.
  • Shamblin Classification (Carotid Body Tumors - CBTs): Guides surgical difficulty.

    Class	Description	Surgical Plane
    I	Small tumor, loosely adherent to carotid vessels.	Easily dissected from adventitia.
    II	Larger, partially surrounds vessels, more adherent.	Dissection in subadventitial plane required.
    III	Tumor encasing carotid artery, often requiring vascular reconstruction.	Subadventitial dissection; may need graft/bypass.

• Radiotherapy (RT):

  • Stereotactic Radiosurgery (SRS) or Fractionated RT.
  • Options for: unresectable tumors, surgical remnants, recurrent disease, elderly/poor surgical candidates, or patient preference.
  • High rates of tumor growth control.

• Observation ("Watchful Waiting"):

  • For small, asymptomatic, slow-growing tumors, especially in elderly or comorbid patients.
  • Requires regular imaging surveillance.

High‑Yield Points - ⚡ Biggest Takeaways

• Most common paraganglioma: Carotid body tumor. Other key sites: glomus jugulare, glomus tympanicum.
• Rule of 10s: 10% bilateral, 10% malignant, 10% familial.
• Glomus tympanicum: Pulsatile tinnitus, red retrotympanic mass (Aquino sign).
• Glomus jugulare: Jugular foramen origin; cranial nerve palsies (IX, X, XI, XII).
• Histology: Classic "Zellballen" (cell ball) pattern.
• Functional tumors secrete catecholamines (hypertension, palpitations).
• Genetic link: SDHx gene mutations are common; SDHB linked to ↑malignancy.