Genetically transmitted disorder characterized by the
development of highly vascularized tumors derived from neuroectodermal
cells, preferentially localized in the carotid body (80% of cases) and in
the glomus jugulare (20% of cases).
Carotid Body Tumors; Chemodectomas; Glomus Jugulare
Tumors; Hereditary Paraganglioma.
Familial paragangliomas, or glomus tumors, are slow
growing, highly vascular, generally benign neoplasms, usually of the head
and neck, that arise from neural crest cells outside of the adrenal medulla.
Tumors arising in chemoreceptor structures include carotid body tumors and
glomus jugulare tumors.
Glomus tumors accounts for only 0.03% of all
neoplasms and 0.6% of head and neck tumors. They are sometimes familial,
bilateral, and associated with other neoplasms. They can be malignant,
although this is rare.
Inheritance is autosomal dominant. The
paraganglioma gene PGL1 has been mapped to 11q22.3-q23. Germline missense
mutations in the gene encoding succinate dehydrogenase subunit D (SDHD) gene
have been identified. The disease is subject to age-dependent penetrance and
Tumors may be bilateral or unilateral. The most
common sites are the carotid body, the vagal body, and the jugulotympanic
site. It is postulated that the tumor starts secondary to stimulus of
hypercarbia or hypoxemia (the carotid bodies are the peripheral
chemoreceptors that act as sensors for both hypoxia and hydrogen ion
concentration). Others postulate that there is a connection between living at high
altitude, emphysema, and carotid body tumors. There may be an association
between paraganglioma and pheochromocytoma. The tumors have a tendency to
reproduce the microscopic structure of the normal carotid body. These
carotid body tumors are referred to as nonfunctional with regards to the
nonchromaffin nature of the tumor, but chemoreceptor function is still
Most patients present for evaluation of an anterior neck
mass discovered on clinical examination or self-examination or detected
during duplex scanning for carotid artery disease. In patients with tympanic
chemodectomas, the condition may be suspected because of tinnitus aurium and
a transtympanic reddish image by otoscopy. Arteriography remains the gold
standard for diagnosis. Doppler color flow imaging, dynamic
angioscintigraphy, CT, and MRI contribute additional information about tumor
Age at onset of symptoms was significantly
different between fathers and children (affected children have earlier age
of onset). Clinical manifestations depend on tumor location and are often
related to the middle ear (pulsatile tinnitus, conductive hearing loss,
aural fullness, discharge or bleeding, and a bluish mass behind the tympanic
membrane are characteristic). Cranial nerve dysfunction (facial paralysis,
dysphonia, marked hearing loss, pain). The most common complaint was
swelling in the anterolateral region of the neck. Familial carotid body
tumors tend to be multiple. All paragangliomas are capable of catecholamine
production. Of the paragangliomas of the head and neck, 1 to 4% can
secrete sufficient amounts of catecholamines to mimic a pheochromocytoma.
Patients with glomus tumors have a higher incidence of developing a
pheochromocytoma, especially those with familial glomus tumor disease. Many
authors believe ...