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and neck, including jugulotympanic, paragangliomas there is, unlike the solitary jugulotympanic paragan-glioma, a preponderance for the male sex and inheritance is autosomal dominant, with increased pene-trance with age [5]. There is evidence from molecular genetic studies that the gene underlying familial para-gangliomas is located on chromosome 11q proximal to the tyrosinase gene locus [59].

The neoplasm is a reddish sprouting mass at its external canal surface. In the jugular variety the petrous temporal bone is largely replaced by red, firm material and the middle ear space is occupied by soft neoplasm as far as the tympanic membrane. The otic capsule is rarely invaded by paraganglioma. Investigation of a paragan-glioma in an autopsy temporal bone by the microslic-ing method showed the origin of the tumour to be in the jugular bulb region and its spread through the petrous bone and middle ear to the tympanic membrane (Fig. 8.15). The histology of paraganglioma is described in Chap. 9 (Fig. 8.16) [55].

The incidence of clinically functioning paraganglio-ma with symptoms and signs of norepinephrine excess, particularly hypertension, is only 1-3% [97].

Jugulotympanic paraganglioma is a neoplasm of slow growth. The jugular variety infiltrates the petrous bone, but distant metastasis is rare. Radiation therapy, and in some cases surgery, offers a high rate of cure for these neoplasms and the number of patients who do badly after such therapy is very small.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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