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Findings suggestive of anomalies of the cranial venous outflow anatomy were frequently observed in both MS patients and healthy controls. Given the normal intracranial venous flow quantification results, it is likely that these findings reflect anatomical variants of venous drainage rather than clinically relevant venous outflow obstructions.

BACKGROUND Extraadrenal paragangliomas of the head and neck are tumors with variable clinical behavior. Because tumor growth as well as surgery can cause disabling loss of function, knowledge of the natural history of paragangliomas is important for the development of treatment strategies. METHODS The tumor volume, growth rate, and tumor doubling time of 48 paragangliomas at different anatomic locations in the head and neck region were estimated retrospectively using sequential radiologic imaging. RESULTS During a mean follow‐up period of 4.2 years, a volume increase of > 20% was observed in 60% of the paragangliomas. In these cases the median growth rate was 1.0 mm/year and the median tumor doubling time was 4.2 years. More growing tumors were observed in intermediate size tumors than in very small or large paragangliomas, suggesting a biphasic growth pattern. CONCLUSIONS The majority of head and neck paragangliomas have a very low growth rate. Although management of paragangliomas also is determined by other parameters, preoperative estimation of the tumor doubling time may influence the treatment proposal. A “wait and scan” policy must be considered in all cases. Cancer 2000;88:2811–6. © 2000 American Cancer Society.