Familial carotid body tumors: a closer look.
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PURPOSE: A family spanning three generations with a history of familial carotid body tumors (CBTs) was studied, and previously proposed hypotheses of tumor characteristics and genetic mode of transmission were addressed. METHODS: Clinically occult lesions in adult subjects were detected by means of high-resolution computed tomography. RESULTS: A 60% incidence of bilaterality of CBTs associated with multiple paragangliomas was noted in the family studied. The genetic mode for CBTs in this family was not simple autosomal dominant transmission and appeared to be paternally directed with complete penetrance. CONCLUSION: In patients with familial CBTs, high-resolution computed tomography is recommended for early screening as a means of prompting diagnosis and definitive treatment, an approach that minimizes morbidity and facilitates surgical excision. (+info)
Mutations in SDHD, a mitochondrial complex II gene, in hereditary paraganglioma.
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Hereditary paraganglioma (PGL) is characterized by the development of benign, vascularized tumors in the head and neck. The most common tumor site is the carotid body (CB), a chemoreceptive organ that senses oxygen levels in the blood. Analysis of families carrying the PGL1 gene, described here, revealed germ line mutations in the SDHD gene on chromosome 11q23. SDHD encodes a mitochondrial respiratory chain protein-the small subunit of cytochrome b in succinate-ubiquinone oxidoreductase (cybS). In contrast to expectations based on the inheritance pattern of PGL, the SDHD gene showed no evidence of imprinting. These findings indicate that mitochondria play an important role in the pathogenesis of certain tumors and that cybS plays a role in normal CB physiology. (+info)
Bilateral carotid body paraganglioma: case report.
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CONTEXT: Surgical treatment of carotid body paragangliomas is a challenge to the surgeon because of the large vascularization of the tumor, involvement of the carotid vessels and the close anatomical relationship with the cranial nerves. CASE REPORT: A 63-year-old patient was submitted to resection of two carotid body paraganglioma tumors found in the right-side and left-side carotid bodies at the bifurcation of the common carotid arteries. Two surgeries were performed at different times and neither of them presented any morbidity. Arteriography was fundamental for diagnosis of the small, asymptomatic tumor on the right side. DESIGN: Case Report (+info)
Baroreflex failure syndrome after bilateral excision of carotid body tumors: an underestimated problem.
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Carotid body tumors (CBTs) are relatively rare paragangliomas that develop from neural crest cells at the bifurcation of the common carotid artery. They are generally slow growing and benign. Excision is currently considered the treatment of choice, although vascular and especially neural injuries are still relatively frequent in patients with large or bilaterally resected tumors. The baroreflex failure syndrome (BFS) has recently been identified as a severe, rarely recognized, and certainly underestimated complication after the bilateral excision of CBTs. The present report describes a case of a bilateral CBT followed by BFS and reviews the experiences reported in the literature. In light of the low incidence of malignancy of these tumors, their biologic behavior, their very high rate of cranial nerve palsy, and the occurrence of BFS in bilaterally resected paragangliomas, the current practice of bilaterally removing these tumors is questioned. (+info)
Power Doppler scanning in the diagnosis of carotid body tumors.
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The aim of this work was to show contribution of power Doppler imaging in the diagnosis of the carotid body tumors. Six patients with a nontender mass beneath the mandibular angle were evaluated with gray scale and power Doppler sonography. Well-defined, solid, weakly hyperechoic masses were noted on gray scale sonography in the carotid bifurcation. Power Doppler sonography showed abundant flow, characterized as an intense blush, throughout the entire tumor in all patients. We believe that invasive and expensive diagnostic modalities are not necessary to evaluate carotid body tumors. Gray scale sonography and power Doppler imaging are sufficient for primary diagnosis of carotid body tumors. (+info)
Malignant carotid body tumor: a case report.
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Carotid body tumors (CBTs) have an unpredictable history with no correlation between histology and clinical behavior. Of reported cases since 1891, local and distant metastases appear in approximately 10% of cases and remain the hallmark of malignancy. Currently, there are not enough data to support a single treatment regimen for malignant CBTs. The reported case demonstrates some unanswered issues with regard to malignant CBTs to include lymph node dissection, the need for carotid resection, and the role of radiation therapy. A 46-year-old pathologist underwent a resection of a Shamblin I CBT, to include jugular lymph node sampling, without complication. There was lymph node involvement, and tumor cells were found on the margins of the pathologic specimen. Subsequent carotid resection with reversed interposition saphenous vein graft and modified neck dissection were performed again without complication. Follow-up at 4 years has been uneventful. Diagnosis of CBTs with the use of magnetic resonance angiography, magnetic resonance imaging, color flow duplex scanning, and the role of arteriography are reviewed. The current treatment options are discussed with reference to primary lymph node sampling, carotid resection, and neck dissection in malignant cases. This case demonstrates that the unpredictable nature of CBTs and their malignant potential warrant aggressive initial local treatment to include jugular lymph node sampling and complete tumor resection. (+info)
Long-term effects of carotid sinus denervation on arterial blood pressure in humans.
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BACKGROUND: After experimental carotid sinus denervation in animals, blood pressure (BP) level and variability increase markedly but normalize to preoperative levels within 10 to 14 days. We investigated the course of arterial BP level and variability after bilateral denervation of the carotid sinus baroreceptors in humans. METHODS AND RESULTS: We studied 4 women (age 41 to 63 years) who were referred for evaluation of arterial baroreflex function because of clinical suspicion of carotid sinus denervation attributable to bilateral carotid body tumor resection. The course of BP level and variability was assessed from repeated office and 24-hour ambulatory measurements (Spacelabs/Portapres) during 1 to 10 years of (retrospective) follow-up. Rapid cardiovascular reflex adjustments to active standing and Valsalva's maneuver were assessed. Office BP level increased from 132/86 mm Hg (range, 118 to 148/80 to 92 mm Hg) before bilateral surgery to 160/105 mm Hg (range, 143 to 194/90 to 116 mm Hg) 1 to 10 years after surgery. During continuous 24-hour noninvasive BP recording (Portapres), a marked BP variability was apparent in all 4 patients. Initial symptomatic hypotension on change to the upright posture and abnormal responses to Valsalva's maneuver were observed. CONCLUSIONS: Acute carotid sinus denervation, as a result of bilateral carotid body tumor resection, has a long-term effect on the level, variability, and rapid reflex control of arterial BP. Therefore, in contrast to earlier experimental observations, the compensatory ability of the baroreceptor areas outside the carotid sinus seems to be of limited importance in the regulation of BP in humans. (+info)
Baroreflex control of muscle sympathetic nerve activity after carotid body tumor resection.
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Bilateral carotid body tumor resection causes a permanent attenuation of vagal baroreflex sensitivity. We retrospectively examined the effects of bilateral carotid body tumor resection on the baroreflex control of sympathetic nerve traffic. Muscle sympathetic nerve activity was recorded in 5 patients after bilateral carotid body tumor resection (1 man and 4 women, 51+/-11 years) and 6 healthy control subjects (2 men and 4 women, 50+/-7 years). Baroreflex sensitivity was calculated from changes in R-R interval and muscle sympathetic nerve activity in response to bolus injections of phenylephrine and nitroprusside. In addition, sympathetic responses to the Valsalva maneuver and cold pressor test were measured. The integrated neurogram of patients and control subjects contained a similar pattern of pulse synchronous burst of nerve activity. Baroreflex control of both heart rate and sympathetic nerve activity were attenuated in patients as compared with control subjects [heart rate baroreflex sensitivity: 3.68+/-0.93 versus 11.61+/-4.72 ms/mm Hg (phenylephrine, P=0.011) and 2.53+/-1.36 versus 5.82+/-1.94 ms/mm Hg (nitroprusside, P=0.05); sympathetic baroreflex sensitivity: 3.70+/-2.90 versus 7.53+/-4.12 activity/100 beats/mm Hg (phenylephrine, P=0.10) and 3.93+/-4.43 versus 15.27+/-10.03 activity/100 beats/mm Hg (nitroprusside, P=0.028)]. The Valsalva maneuver elicited normal reflex changes in muscle sympathetic nerve activity, whereas heart rate responses were blunted in the patients with bilateral carotid body tumor resection. Maximal sympathetic responses to the cold pressor test did not differ between the two groups. Denervation of carotid sinus baroreceptors as the result of bilateral carotid body tumor resection produces chronic impairment of baroreflex control of both heart rate and sympathetic nerve activity. During the Valsalva maneuver, loss of carotid baroreflex control of heart rate is less well compensated for by the extra carotid baroreceptors than the control of muscle sympathetic nerve activity. (+info)