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"Comet tail sign": A pitfall of post-gadolinium magnetic resonance imaging findings for metastatic brain tumors.

Mitsuya K, Nakasu Y, Narita Y, Nakasu S, Ohno M, Miyakita Y, Abe M, Ito I, Hayashi N, Endo M - J. Neurooncol. (2016)

Bottom Line: A highly enhanced cap attached to the surface of metastatic tumors in the brain parenchyma is occasionally encountered on magnetic resonance (MR) images.The purpose of this study was to demonstrate the features of the CTS using MR imaging and pathological findings, and to clarify its clinical relevance.We speculate that the CTS does not contain neoplastic tissues but is observed as a result of the leakage of contrast medium from the tumor body into the interstitial space of the white matter.

View Article: PubMed Central - PubMed

Affiliation: Division of Neurosurgery, Shizuoka Cancer Center, 1007 Naga-izumi, Shizuoka, 411-8777, Japan. k.mitsuya@scchr.jp.

ABSTRACT
A highly enhanced cap attached to the surface of metastatic tumors in the brain parenchyma is occasionally encountered on magnetic resonance (MR) images. This atypical enhanced cap tends to occur in severe peritumoral edema and may produce the characteristic bulge of a metastatic mass lesion termed the "comet tail sign" (CTS). The purpose of this study was to demonstrate the features of the CTS using MR imaging and pathological findings, and to clarify its clinical relevance. We selected 21 consecutive cases of newly diagnosed metastases from MR imaging studies that demonstrated the CTS; all had diffuse peritumoral edema. The MR T2-weighted images showed similarly homogenous and high intensity signals in both the tail and peritumoral edema. Fourteen of the 21 patients underwent surgical resection of their tumors, and 12 tails were separately removed for pathological examination, no tumor cells which revealed. We speculate that the CTS does not contain neoplastic tissues but is observed as a result of the leakage of contrast medium from the tumor body into the interstitial space of the white matter. Although CTS is a peculiar and uncommon enhancement pattern, it has clinical significance in determining the extent of the margin for invasive local treatments, such as surgical resection or stereotactic radiotherapy; this is particularly true in and near the eloquent areas.

No MeSH data available.


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a MR T1-CE showing the CTS in the right frontal metastatic brain tumor of a patient with lung cancer. b MR T1-CE image showing that the tail of the CTS had disappeared after administration of corticosteroids
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Fig4: a MR T1-CE showing the CTS in the right frontal metastatic brain tumor of a patient with lung cancer. b MR T1-CE image showing that the tail of the CTS had disappeared after administration of corticosteroids

Mentions: Post-gadolinium T1WI demonstrated more intense and homogenous enhancement in the tail than in the main body (Fig. 3). T2WI revealed that the main body of the tumor had a signal that ranged from low-intensity to isointensity; however, the tail of the CTS had a high-intensity signal buried in peritumoral diffuse edema (Figs. 1b and 2b). When these metastatic brain tumors with CTS were situated near the ventricle, the tails always pointed towards the ventricle; more specifically, they pointed towards the anterior horn (Fig. 3a) and the posterior horn (Fig. 3b) of the lateral ventricle, and towards the fourth ventricle (Fig. 3c). The tail of the CTS disappeared concurrently with the decrease in perifocal edema in a single patient after administration of dexamethasone for 1 week (Fig. 4).Fig. 1


"Comet tail sign": A pitfall of post-gadolinium magnetic resonance imaging findings for metastatic brain tumors.

Mitsuya K, Nakasu Y, Narita Y, Nakasu S, Ohno M, Miyakita Y, Abe M, Ito I, Hayashi N, Endo M - J. Neurooncol. (2016)

a MR T1-CE showing the CTS in the right frontal metastatic brain tumor of a patient with lung cancer. b MR T1-CE image showing that the tail of the CTS had disappeared after administration of corticosteroids
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835516&req=5

Fig4: a MR T1-CE showing the CTS in the right frontal metastatic brain tumor of a patient with lung cancer. b MR T1-CE image showing that the tail of the CTS had disappeared after administration of corticosteroids
Mentions: Post-gadolinium T1WI demonstrated more intense and homogenous enhancement in the tail than in the main body (Fig. 3). T2WI revealed that the main body of the tumor had a signal that ranged from low-intensity to isointensity; however, the tail of the CTS had a high-intensity signal buried in peritumoral diffuse edema (Figs. 1b and 2b). When these metastatic brain tumors with CTS were situated near the ventricle, the tails always pointed towards the ventricle; more specifically, they pointed towards the anterior horn (Fig. 3a) and the posterior horn (Fig. 3b) of the lateral ventricle, and towards the fourth ventricle (Fig. 3c). The tail of the CTS disappeared concurrently with the decrease in perifocal edema in a single patient after administration of dexamethasone for 1 week (Fig. 4).Fig. 1

Bottom Line: A highly enhanced cap attached to the surface of metastatic tumors in the brain parenchyma is occasionally encountered on magnetic resonance (MR) images.The purpose of this study was to demonstrate the features of the CTS using MR imaging and pathological findings, and to clarify its clinical relevance.We speculate that the CTS does not contain neoplastic tissues but is observed as a result of the leakage of contrast medium from the tumor body into the interstitial space of the white matter.

View Article: PubMed Central - PubMed

Affiliation: Division of Neurosurgery, Shizuoka Cancer Center, 1007 Naga-izumi, Shizuoka, 411-8777, Japan. k.mitsuya@scchr.jp.

ABSTRACT
A highly enhanced cap attached to the surface of metastatic tumors in the brain parenchyma is occasionally encountered on magnetic resonance (MR) images. This atypical enhanced cap tends to occur in severe peritumoral edema and may produce the characteristic bulge of a metastatic mass lesion termed the "comet tail sign" (CTS). The purpose of this study was to demonstrate the features of the CTS using MR imaging and pathological findings, and to clarify its clinical relevance. We selected 21 consecutive cases of newly diagnosed metastases from MR imaging studies that demonstrated the CTS; all had diffuse peritumoral edema. The MR T2-weighted images showed similarly homogenous and high intensity signals in both the tail and peritumoral edema. Fourteen of the 21 patients underwent surgical resection of their tumors, and 12 tails were separately removed for pathological examination, no tumor cells which revealed. We speculate that the CTS does not contain neoplastic tissues but is observed as a result of the leakage of contrast medium from the tumor body into the interstitial space of the white matter. Although CTS is a peculiar and uncommon enhancement pattern, it has clinical significance in determining the extent of the margin for invasive local treatments, such as surgical resection or stereotactic radiotherapy; this is particularly true in and near the eloquent areas.

No MeSH data available.


Related in: MedlinePlus