A chemodectoma is a highly characteristic tumor that arises most commonly from the carotid body and glomus jugulare. A chemodectoma of the orbit in a 55-year-old housewife is reported. Decreased blood pressure and marked fluctuation of pulse rate noted upon manipulation of the tumor might be explained on the basis of catecholamine secretion b y the tumor cells. The pathologist cannot on a histologic basis predict when a chemodectoma is apt to metastasize, since benign-appearing rumors have metastasized after protracted latent periods. However, metastases irom these tumors are rare and are predominantly to the lungs, but may involve the skeleton. Multicentric chemodectomas are more frequent among patients with a familial history of carotid body tumors. Surgical excision of these neoplasms is the treatment of choice when possible, but inoperable tumors may be expected to respond to radiation therapy.
CHEMODECTOMA IS A HIGHLY CHARACTER-
A istic tumor that arises most commonly from the carotid body and glomus jugulare. Various terms have been used to describe tumors arising from the carotid body, including "adenomas," "chromaffinomas," "nonchromaffin paragangliomas," and "endotheliomas." Mulligan21 suggested the term "chemodectoma" since the glomerae from which these tumors originate are chemoreceptors reacting to changes in the pH of the blood.