RT Journal Article SR Electronic T1 Fluid-Fluid Level Formation: A Rare Finding of Extracranial Head and Neck Schwannomas JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 1451 OP 1453 DO 10.3174/ajnr.A1511 VO 30 IS 7 A1 H. Kato A1 M. Kanematsu A1 K. Mizuta A1 M. Aoki A1 K. Yamada A1 H. Yamakawa A1 T. Iwama A1 Y. Hirose YR 2009 UL http://www.ajnr.org/content/30/7/1451.abstract AB SUMMARY: We present 3 cases of extracranial head and neck schwannomas exhibiting fluid-fluid levels. In the described cases, CT and MR imaging showed predominantly cystic components, intermixed with cellular components. Histopathologic examinations of excised specimens revealed hemosiderin deposition, reflecting intratumoral hemorrhages, which was presumably a cause of fluid-fluid levels. Although fluid-fluid levels are nonspecific findings, schwannoma should be considered when radiologic images demonstrate marked cystic formation with fluid-fluid levels in extracranial head and neck tumors.