Carotid body tumors in humans: genetics and epidemiology.

Genetic factors in the etiology of carotid body tumors (CBT) were sought in a medical record review of 222 histologically diagnosed cases at 12 U.S. medical centers. Patients in the series, which had a marked female predominance (146 females:76 males), usually developed tumors between the fourth and seventh decades of life (mean, 44.7 yr). In 16 patients who also had other extra-adrenal paragangliomas, suggesting a multiple primary tumor syndrome, CBT were diagnosed significantly earlier (mean, 35.4 yr; P less than 0.01). The occurrence of thyroid cancer in 5 other patients appeared to be excessive. Familial CBT was recognized in 16 patients from 13 affected families, including 9 newly ascertained kindreds. Compared with non-familial lesions, familial CBT tended to develop bilaterally (38% vs. 8% unilaterally) and at slightly earlier ages (41.6 vs. 44.9 yr). CBT was reported to occur in an autosomal dominant pattern in some families and within sibships in others; relatives were not examined for confirmation. The familial findings are generally consistent with a two-step mutation model of the development of hereditary and nonhereditary CBT; apparent deviations from the model might be clarified with additional data on this rare neoplasm.