Paraganglioma

Paraganglioma
Other names	Chemodectoma, paraganglioma, carotid body tumour, glomus cell tumour
Micrograph of a carotid body tumor (a type of paraganglioma)
Specialty	Oncology

A paraganglioma is a rare

The paragangliomas appear grossly as sharply circumscribed polypoid masses and they have a firm to rubbery consistency. They are highly vascular tumors and may have a deep red color.^{[citation needed]}

On microscopic inspection, the tumor cells are readily recognized. Individual tumor cells are polygonal to oval and are arranged in distinctive cell balls, called Zellballen.^[8] These cell balls are separated by fibrovascular stroma and surrounded by sustentacular cells.^{[citation needed]}

By light microscopy, the differential diagnosis includes related neuroendocrine tumors, such as

About 85% of paragangliomas develop in the abdomen; only 12% develop in the chest and 3% in the head and neck region (the latter are the most likely to be symptomatic). While most are single, rare multiple cases occur (usually in a hereditary syndrome). ^[citation needed] Paragangliomas are described by their site of origin and are often given special names:

• Head and neck paraganglioma (HNPGL): There are various types of head and neck paraganglioma; they may have specialized names depending on the precise location.^[9]
  • Carotid paraganglioma (carotid body tumor): Is the most common of the head and neck paragangliomas. It usually presents as a painless neck mass, but larger tumors may cause cranial nerve palsies, usually of the vagus nerve and hypoglossal nerve.
  • Glomus jugulare, also known as jugulotympanic paraganglioma: Both commonly present as a middle ear mass resulting in tinnitus (in 80%) and hearing loss (in 60%). The cranial nerves of the jugular foramen may be compressed, resulting swallowing difficulty, or ipsilateral weakness of the upper trapezius and sternocleiodomastoid muscles (from compression of the spinal accessory nerve). These patients present with a reddish bulge behind an intact ear drum. This condition is also known as the "Red drum". On application of pressure to the external ear canal with the help of a pneumatic ear speculum the mass could be seen to blanch. This sign is known as "Brown's sign". A deficient bony plate along the tympanic portion of the internal carotid artery (aberrant ICA) is a normal variant and can be mistaken with glomus jugulare.^[10]
• Organ of Zuckerkandl: A collection of paraganglia near the bifurcation of the aorta, comprising a small mass of neural crest-derived chromaffin cells. Serves as a common origin of abdominal paragangliomas.
• Vagal paraganglioma: These are the least common of the head and neck paragangliomas. They usually present as a painless neck mass, but may result in dysphagia, hoarseness, or coughing with compression of the mass.
• Pulmonary paraganglioma: These occur in the lung and may be either single or multiple.^[11]
• Other sites: Rare sites of involvement are the
  thoracic inlet
  , as well as the bladder in extremely rare cases.

Diagnosis

Classification

Paragangliomas originate from paraganglia in chromaffin-negative glomus cells derived from the embryonic neural crest, functioning as part of the sympathetic nervous system (a branch of the autonomic nervous system). These cells normally act as special chemoreceptors located along blood vessels, particularly in the carotid bodies (at the bifurcation of the common carotid artery in the neck) and in aortic bodies (near the aortic arch).^{[citation needed]}

Accordingly, paragangliomas are categorised as originating from a neural cell line in the

Gallium-68 DOTATATE PET/CT imaging modality may be used to confirm the presence of a paraganglioma.[13]

Treatment

The main treatment modalities are

• 
  Micrograph of a carotid body tumor
• 
  Glomus jugulare tumor
• 
  Ectopic functional paraganglioma (glomus jugulare) in a patient with VHL. T2 weighted MRI at the same location demonstrates a high signal mass consistent with a paraganglioma. Extra adrenal paragangliomas can be found in VHL (arrow).
• 
  S100

  immunostain

  highlighting the sustentacular cells in a paraganglioma
• 
  Digital subtraction arteriogram of carotid body tumor and jugular paraganglioma

See also

• Gangliocytic paraganglioma
• Pheochromocytoma

References