Fact-sheet: Paraganglioma of neck - glomus tumor


Updated on 08/26/2020 at 4:29 PM

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Definition

Tumor derived from the neuroectoderm.
Paragangliomas arising from the extra-adrenal parasympathetic nervous system, often non-secreting (non-functional).
Possible genetic predisposition in 30% of cases (VHL, MEN, NF1, SDHx).

Prevalence in women between 30 and 60 years of age.

Possible locations: -
at the carotid body -
at the skull base along the vagus nerve -
in the jugulotympanic region
Most often a benign tumor.
Malignancy is confirmed only in the presence of metastasis.

Growth is fairly slow, keeping the tumor asymptomatic for a long time.

Clinical features

Symptoms result from compression of adjacent noble structures (nerves and vessels)

  • Asymptomatic for a long time
  • Palpable (pulsatile) laterocervical mass
  • Pulsatile tinnitus and hearing loss if involving the middle ear
  • Red retrotympanic mass found on otoscopy
  • Vagus nerve (CN X) palsy, Horner syndrome, dysphagia

Laboratory findings

Non-secreting paraganglioma in most cases, therefore no elevation of urinary and plasma metanephrines

Radiography

Non-contributory

Ultrasound

  • Well-defined solid mass, isoechoic, deep to the muscular planes.
    Deviation of the carotid axes
  • Hypervascularity on Color Doppler

CT

  • Hypervascular mass syndrome arising from a compatible structure (as mentioned above)
  • Well-defined tumor, displacing adjacent structures
  • Osteolysis of osseous structures with a "wet sugar" appearance
  • Hypodense areas of central necrosis
  • Rapid enhancement in the arterial phase
  • "Lyre" appearance on sagittal images in cases of glomus involvement, with the tumor "splaying" and widening the angle formed by the internal and external carotid arteries

MRI

  • T1: Intermediate signal
  • T2: Hyperintense signal with areas of vascular signal void,
    hypointense on T2 "flow void"
  • After gadolinium injection: intense early enhancement, early venous return
  • Diffusion: mild hyperintensity
  • "Salt and pepper" appearance

Vascular intervention

  • Biopsy is hazardous
  • Preoperative embolization possible to limit intraoperative bleeding

Nuclear medicine

  • 18-FDG PET: excellent sensitivity, hypermetabolism, used for staging workup
  • MIBG scintigraphy
  • 18F-DOPA scintigraphy

Management

  • Multidisciplinary tumor board
    (staging workup, pre-embolization, radiosurgery, stereotactic radiotherapy, simple surveillance)

Classification

Shamblin classification, for carotid body tumors

  • Small, without vascular encasement, with a clear cleavage plane
  • Intermediate
  • Large, encasing the vessels.

Differential diagnosis

  • Mucosal adenoma
  • Squamous cell carcinoma
  • Hemangioma
  • Chondrosarcoma
  • Skull base schwannoma
  • Neurofibroma