Microhemorrhage, a possible mechanism for cyst formation in vestibular schwannomas

Park, Chul‐Kee; Kim, Dong Chul; Park, Sung Sup; Kim, Jeong Eun; Paek, Sun Ha; Kim, Dong Gyu; Jung, Hee-Won

doi:10.3171/jns.2006.105.4.576

Cited by 92 publications

(87 citation statements)

References 27 publications

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“…4 Hemosiderin deposition was obvious in all of our cases, and thrombotic vessels and abnormal vessel proliferation were observed in cases 2 and 3. Furthermore, xanthochromic fluid within the cysts was found during surgery, which supports the above hypothesis.…”

Section: Discussionmentioning

confidence: 92%

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Fluid-Fluid Level Formation: A Rare Finding of Extracranial Head and Neck Schwannomas

Kato¹,

Kanematsu²,

Mizuta³

et al. 2009

AJNR Am J Neuroradiol

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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. Schwannoma is one of the most common soft tissue tumors and constitutes approximately 5% of all benign neoplasms. The head and neck region is favored, and approximately 25% to 45% of benign schwannomas arise in this area. However, head and neck schwannomas usually occur in the intracranial region and rarely occur extracranially. Although cystic formations are often observed in intracranial and extracranial schwannomas, multicystic formations and intratumoral hemorrhage in schwannomas are relatively rare. Here, we describe the CT and MR imaging findings of 3 patients with extracranial head and neck schwannomas that exhibited fluid-fluid levels, which presumably reflected intratumoral hemorrhage. Case Reports Case 1An 85-year-old woman noticed a painless mass on the right side of her neck 4 years before presentation. The mass had grown gradually and had not produced cranial nerve symptoms. Unenhanced CT scan demonstrated a 42 ϫ 40 ϫ 72-mm, well-demarcated, hypoattenuated lesion with a fluid-fluid level, located in the right middle aspect of the neck ( Fig 1A). On unenhanced T1-weighted and T2-weighted MR images, the lesion was found to contain a cystic cavity with a fluid-fluid level and to compress the right common carotid artery anteriorly ( Fig 1B). Contrast-enhanced MR images demonstrated a laminated structure, double ringlike enhancement, and slightly mottled enhancement in the outer layer. An open biopsy was performed, and whitish fibrous capsules and internal serous fluid were found. The biopsy also confirmed that the lesion was continuous with the vagus nerve. A histopathologic examination of the biopsy specimen revealed a severely degenerated schwannoma with fibrosis and edema. Hemosiderin deposition was also confirmed, especially within the fibrous tissue. Case 2A 44-year-old man had experienced a pain in the back of his head and neck for 1 year, but the cause of his symptom had not been determined. At presentation, he had lower cranial nerve symptoms, namely, paralysis of the soft palate attributed to vagus nerve palsy, and a deviation toward the left side during tongue protrusion because of hypoglossal nerve palsy. Unenhanced CT scan revealed a 44 ϫ 30 ϫ 44-mm, well-demarcated, hypoattenuated lesion with a hyperattenuated area in a gravity-dependent portion, located in the left parapharyngeal space (Fig 2A). On unenhanced T1-weighted and T2-weighted MR images, the lesion was visualized as a unilocular cystic cavity...

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Section: Discussionmentioning

confidence: 92%

“…However, the relationship be- tween cystic formation and the distribution of Antoni cell types is not always observed. 4 In cases 2 and 3, cellular Antoni type A tissue occupied most of the tumor.…”

Section: Discussionmentioning

confidence: 99%

Fluid-Fluid Level Formation: A Rare Finding of Extracranial Head and Neck Schwannomas

Kato¹,

Kanematsu²,

Mizuta³

et al. 2009

AJNR Am J Neuroradiol

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“…16 By using T2-weighted sequence, Ishii et al 14 demonstrated microhemorrhages in 5 of 12 VS measuring more than 25 mm in diameter. Park et al 15 demonstrated microhemorrhage in 35% of VS in their study by using the T2-weighted sequence, though histopathologic examination revealed hemosiderin in all cases. In our study, T2*-weighted GRE images demonstrated microhemorrhages in 15 of 16 VS, resulting in a sensitivity of 93.8%, a specificity and positive predictive value of 100%, and a negative predictive value of 83.3% with T2*-weighted GRE sequences in the detection of microhemorrhages, whereas T2-weighted TSE and FLAIR sequences showed microhemorrhages in only 2 tumors, resulting in a sensitivity of 12.5%.…”

Section: Discussionmentioning

confidence: 99%

“…13 Neoplastic Schwann cells themselves may show hemosiderin because of their phagocytic properties, similar to macrophages. 13 Although MR imaging is exquisitely sensitive for the detection of microhemorrhage, only a few MR studies in the literature have shown the presence of microhemorrhages in VS. 14,15 The major reason for this could be the use of the T2-weighted sequence, which is inherently less sensitive than the T2*-weighted GRE sequence in the identification of microhemorrhage in these studies. 16 By using T2-weighted sequence, Ishii et al 14 demonstrated microhemorrhages in 5 of 12 VS measuring more than 25 mm in diameter.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, microhemorrhages have been thought to play a dominant role in the development of cystic changes in VS. 15 These cystic changes, in turn, may induce large intratumoral hemorrhage and, at times, subarachnoid hemorrhage with adverse outcome. 22,23 Misra et al 22 believe urgent surgery may be needed in cystic VS to avoid the risks for a large hemorrhage.…”

Section: Discussionmentioning

confidence: 99%

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Intratumoral Microhemorrhages on T2*-Weighted Gradient-Echo Imaging Helps Differentiate Vestibular Schwannoma From Meningioma

Thamburaj

Radhakrishnan

Thomas

et al. 2007

AJNR Am J Neuroradiol

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“Flow‐void” sign at MR imaging: A rare finding of extracranial head and neck schwannomas

Kato

Kanematsu

Mizuta

et al. 2010

Magnetic Resonance Imaging

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The authors present two cases of extracranial head and neck schwannomas that exhibited the “flow‐void” sign at MR imaging. In the described cases, MR images showed intratumoral signal voids, which corresponded to dilated vessels. Dynamic contrast‐enhanced CT also demonstrated dilated vessels within the tumors on the arterial phase and tumor parenchymal enhancement on the delayed phase. Histopathologic examinations of excised specimens revealed thin‐walled, dilated abnormal vessels with or without hyaline degeneration. Schwannoma should be considered when MR images demonstrate the “flow‐void” sign in extracranial head and neck tumors. J. Magn. Reson. Imaging 2010;31:703–705. © 2010 Wiley‐Liss, Inc.

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Microhemorrhage, a possible mechanism for cyst formation in vestibular schwannomas

Abstract: Intratumoral microhemorrhage is a possible mechanism of pathogenesis in cystic VS.

Cited by 92 publications

References 27 publications

Fluid-Fluid Level Formation: A Rare Finding of Extracranial Head and Neck Schwannomas

Fluid-Fluid Level Formation: A Rare Finding of Extracranial Head and Neck Schwannomas

Intratumoral Microhemorrhages on T2*-Weighted Gradient-Echo Imaging Helps Differentiate Vestibular Schwannoma From Meningioma

“Flow‐void” sign at MR imaging: A rare finding of extracranial head and neck schwannomas

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