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systemic examination did not reveal any abnormality. A noncontrast cranial CT showed a sharply delineated fat attenuation lesion within the quadrigeminal plate and extending into the cistern on the right side with focal cisternal widening [Figure 2a and b]. An MRI study confirmed the presence of a focal lesion within the quadrigeminal cistern. The lesion demonstrated marked hyperintensity on T1‑weighted (T1W) images with relatively less hyperintensity on T2‑weighted (T2W) images with suppression of signal on short T1 inversion recovery (STIR) sequence confirming the fatty nature of the lesion [Figure 2c‑f]. No other intracranial abnormality was noted.
Access this article online Quick Response Code
Website: www.neurologyindia.com DOI: 10.4103/0028-3886.158250 PMID: xxxxx
Quadrigeminal cistern lipoma revisited
The third case, a 42‑year‑old female, presented with recurrent episodes of severe headache of 4 months duration and being previously treated with the clinical diagnosis of migraine. Her general and neurological examination was normal. An MRI of the brain was performed which showed a small focus of fat signal intensity within the quadrigeminal cistern. The lesion was hyperintense on T1W images, with relatively less hyperintensity on T2W and fluid‑attenuated inversion recovery images, with no mass effect or ventricular dilatation [Figure 3a‑c]. No other abnormal findings were noted.
Sir, We wish to share our experience with three cases of quadrigeminal cistern lipomas, all of whom were discovered incidentally during computed tomography/magnetic resonance imaging (CT/MRI) examination of patients for related or unrelated conditions. The first case, a 31‑year‑old male, presented with a history of minor head injury with no loss of consciousness, convulsions or vomiting. A noncontrast cranial CT study was performed which revealed a fat attenuation lesion on the left side of the quadrigeminal cistern [Figure 1]. No other intracranial pathology was detected.
All the three patients did not require any surgical intervention and were managed conservatively. They are on a regular follow‑up. Intracranial lipomas are neither tumors nor hamartomas. They represent developmental anomalies resulting from abnormal
The second case, a 36‑year‑old male, presented with recurrent headache and dizziness. His neurological and
a
b
Figure 1: (a and b) Axial computed tomography scan shows a fat attenuation lesion in the left quadrigeminal cistern suggestive of a lipoma
Neurology India / May 2015 / Volume 63 / Issue 3
441
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Letters to Editor
a
b
c
d
a
b
c Figure 3: (a-c) Magnetic resonance imaging of the brain with axial T1weighted (a), T2-weighted (b) and fluid-attenuated inversion recovery (c) images showing a small lesion which is hyperintense on all sequences within the left quadrigeminal cistern suggestive of a lipoma
parenchyma, cranial nerves, vessels or with an obstructive hydrocephalus.[2,3] e
f
Figure 2: (a and b) Axial computed tomography scan shows a lipoma in the right quadrigeminal cistern; unenhanced axial (c and d) and sagittal (e) T1-weighted magnetic resonance images show a hyperintense lesion within the quadrigeminal cistern. The lesion is relatively less hyperintense on T2-weighted image (d) and is suppressed on short T1 inversion recovery image (f) thereby confirming the fatty nature of the lesion
differentiation of embryologic meninx primitiva (the mesenchymal anlage of the meninges) during the development of the subarachnoid cisterns. The relative frequency of the various locations of the lipomas correspond to the temporal sequence of dissolution of the meninx primitiva. The lipomas are frequently associated with abnormal development and hypoplasia of adjacent structures such as the corpus callosum, vermis, and inferior colliculi.[1] Quadrigeminal cistern lipomas account for approximately 10–25% of all intracranial lipomas. Generally asymptomatic, these are detected incidentally at imaging, and have a fairly diagnostic imaging characteristics on CT or MRI. Hence, histopathologic confirmation is practically never required. The larger lesions may, however, present with symptoms resulting from compression of the adjacent brain 442
The imaging features of quadrigeminal cistern lipomas are quite characteristic and the fatty nature of the lesion can be confidently established by its typical low attenuation values (−20 to −80 HU) on CT and the short T1 and T2 sequences on MRI. Fat suppression MRI sequences like STIR are useful for confirming the fatty nature of the lipoma.[4] Small quadrigeminal lipomas generally do not require surgery because these tumors rarely reach a size sufficient to cause mass effect or intracranial hypertension. Surgical removal is also discouraged due to the dense vasculature of the lipoma and its tendency to adhere to the surrounding neural tissue making resection technically difficult.[5] If the lesion progresses in size and causes ventricular obstruction and symptoms of raised intracranial pressure or compression of adjacent neural structures occur, surgical intervention is indicated.
Anu Kapoor, Harsha Vardhana K. R, Mahesh D. Dudhat1, Phani Chakravarty Mutnuru Department of Radiology and Imageology, NIMS, 1Department of Radiology, Image Hospital, Hyderabad, Telangana, India
Neurology India / May 2015 / Volume 63 / Issue 3
E‑mail: [email protected]
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Letters to Editor
References 1. 2. 3. 4. 5.
Truwit CL, Barkovich AJ. Pathogenesis of intracranial lipoma: An MR study in 42 patients. AJR Am J Roentgenol 1990;155:855‑64. Senoglu M, Altun I. Lipoma of the quadrigeminal plate cistern. Internet J Radiol 2009;10:11. Yilmazlar S, Kocaeli H, Aksoy K. Quadrigeminal cistern lipoma. J Clin Neurosci 2005;12:596‑9. Ogbole G, Kazaure I, Anas I. Quadrigeminal plate cistern lipoma. BMJ Case Rep 2009; doi: 10.1136/bcr. 07.2009.2110. Yilmaz N, Unal O, Kiymaz N, Yilmaz C, Etlik O. Intracranial lipomas – A clinical study. Clin Neurol Neurosurg 2006;108:363‑8. Access this article online Quick Response Code
Website: www.neurologyindia.com DOI: 10.4103/0028-3886.158254 PMID: xxxxx
Hemifacial spasm associated with vertebral artery fenestration Sir, A 65‑year‑old woman presented with left hemifacial spasm (HFS) that had persisted for 4 years. Magnetic resonance angiography (MRA) demonstrated an elongated vertebral artery (VA) with a fenestration on the left side [Figure 1a]. Heavily T2‑weighted magnetic resonance images revealed a portion of the fenestration of the left VA
a
as a suspected offending vessel compressing the root exit zone (REZ) of the left facial nerve [Figure 1b]. The patient underwent microvascular decompression (MVD). A nerve bundle (a hypoglossal nerve) was observed passing through the fenestration [Figure 2a]. The medial portion of the VA fenestration compressed the REZ of the facial nerve, confirming the VA as an offending vessel [Figure 2]. The artery was displaced to the lateral‑caudal side with a Teflon felt and prosthesis was inserted between the VA fenestration and the cerebellum. As a result, the vessel was detached from the REZ securely [Figure 2b]. After operation, HFS disappeared, and no neurological deficits were detected. The arterial fenestrations usually do not have clinical significance, but in rare occasions may cause neurological symptoms or are associated with cerebral aneurysms, dissection, or arteriovenous malformation. [1] A recent large‑scale study using MRA demonstrated that fenestrations in all locations were found in 2.8% of the study population, and fenestration of the intracranial VA was found in 0.54%. In cases of VA‑associated HFS or HFS caused by sandwich‑type compression between posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA), the outcome of MVD is generally poor.[2] More difficult techniques are required for VA‑associated HFS because of the presence of arterial sclerosis, decreased mobility, anatomical variations like dolichoectatic VA, and perforator disturbance.[2] In the present case of HFS caused by fenestrated VA, careful investigation around the VA fenestration was necessary because unexpected perforators may arise from
b
Figure 1: (a) MRA demonstrating the vertebrobasilar system deviating to the left side with a left VA fenestration (arrow). (b) Thin-slice, heavily T2-weighted magnetic resonance images demonstrating a portion of the fenestrated VA attaching to the REZ of the left facial nerve (arrows)
Neurology India / May 2015 / Volume 63 / Issue 3
443
Copyright of Neurology India is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Copyright of Neurology India is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Letters to Editor
systemic examination did not reveal any abnormality. A noncontrast cranial CT showed a sharply delineated fat attenuation lesion within the quadrigeminal plate and extending into the cistern on the right side with focal cisternal widening [Figure 2a and b]. An MRI study confirmed the presence of a focal lesion within the quadrigeminal cistern. The lesion demonstrated marked hyperintensity on T1‑weighted (T1W) images with relatively less hyperintensity on T2‑weighted (T2W) images with suppression of signal on short T1 inversion recovery (STIR) sequence confirming the fatty nature of the lesion [Figure 2c‑f]. No other intracranial abnormality was noted.
Access this article online Quick Response Code
Website: www.neurologyindia.com DOI: 10.4103/0028-3886.158250 PMID: xxxxx
Quadrigeminal cistern lipoma revisited
The third case, a 42‑year‑old female, presented with recurrent episodes of severe headache of 4 months duration and being previously treated with the clinical diagnosis of migraine. Her general and neurological examination was normal. An MRI of the brain was performed which showed a small focus of fat signal intensity within the quadrigeminal cistern. The lesion was hyperintense on T1W images, with relatively less hyperintensity on T2W and fluid‑attenuated inversion recovery images, with no mass effect or ventricular dilatation [Figure 3a‑c]. No other abnormal findings were noted.
Sir, We wish to share our experience with three cases of quadrigeminal cistern lipomas, all of whom were discovered incidentally during computed tomography/magnetic resonance imaging (CT/MRI) examination of patients for related or unrelated conditions. The first case, a 31‑year‑old male, presented with a history of minor head injury with no loss of consciousness, convulsions or vomiting. A noncontrast cranial CT study was performed which revealed a fat attenuation lesion on the left side of the quadrigeminal cistern [Figure 1]. No other intracranial pathology was detected.
All the three patients did not require any surgical intervention and were managed conservatively. They are on a regular follow‑up. Intracranial lipomas are neither tumors nor hamartomas. They represent developmental anomalies resulting from abnormal
The second case, a 36‑year‑old male, presented with recurrent headache and dizziness. His neurological and
a
b
Figure 1: (a and b) Axial computed tomography scan shows a fat attenuation lesion in the left quadrigeminal cistern suggestive of a lipoma
Neurology India / May 2015 / Volume 63 / Issue 3
441
[Downloaded free from http://www.neurologyindia.com on Tuesday, June 09, 2015, IP: 61.16.135.116]
Letters to Editor
a
b
c
d
a
b
c Figure 3: (a-c) Magnetic resonance imaging of the brain with axial T1weighted (a), T2-weighted (b) and fluid-attenuated inversion recovery (c) images showing a small lesion which is hyperintense on all sequences within the left quadrigeminal cistern suggestive of a lipoma
parenchyma, cranial nerves, vessels or with an obstructive hydrocephalus.[2,3] e
f
Figure 2: (a and b) Axial computed tomography scan shows a lipoma in the right quadrigeminal cistern; unenhanced axial (c and d) and sagittal (e) T1-weighted magnetic resonance images show a hyperintense lesion within the quadrigeminal cistern. The lesion is relatively less hyperintense on T2-weighted image (d) and is suppressed on short T1 inversion recovery image (f) thereby confirming the fatty nature of the lesion
differentiation of embryologic meninx primitiva (the mesenchymal anlage of the meninges) during the development of the subarachnoid cisterns. The relative frequency of the various locations of the lipomas correspond to the temporal sequence of dissolution of the meninx primitiva. The lipomas are frequently associated with abnormal development and hypoplasia of adjacent structures such as the corpus callosum, vermis, and inferior colliculi.[1] Quadrigeminal cistern lipomas account for approximately 10–25% of all intracranial lipomas. Generally asymptomatic, these are detected incidentally at imaging, and have a fairly diagnostic imaging characteristics on CT or MRI. Hence, histopathologic confirmation is practically never required. The larger lesions may, however, present with symptoms resulting from compression of the adjacent brain 442
The imaging features of quadrigeminal cistern lipomas are quite characteristic and the fatty nature of the lesion can be confidently established by its typical low attenuation values (−20 to −80 HU) on CT and the short T1 and T2 sequences on MRI. Fat suppression MRI sequences like STIR are useful for confirming the fatty nature of the lipoma.[4] Small quadrigeminal lipomas generally do not require surgery because these tumors rarely reach a size sufficient to cause mass effect or intracranial hypertension. Surgical removal is also discouraged due to the dense vasculature of the lipoma and its tendency to adhere to the surrounding neural tissue making resection technically difficult.[5] If the lesion progresses in size and causes ventricular obstruction and symptoms of raised intracranial pressure or compression of adjacent neural structures occur, surgical intervention is indicated.
Anu Kapoor, Harsha Vardhana K. R, Mahesh D. Dudhat1, Phani Chakravarty Mutnuru Department of Radiology and Imageology, NIMS, 1Department of Radiology, Image Hospital, Hyderabad, Telangana, India
Neurology India / May 2015 / Volume 63 / Issue 3
E‑mail: [email protected]
[Downloaded free from http://www.neurologyindia.com on Tuesday, June 09, 2015, IP: 61.16.135.116]
Letters to Editor
References 1. 2. 3. 4. 5.
Truwit CL, Barkovich AJ. Pathogenesis of intracranial lipoma: An MR study in 42 patients. AJR Am J Roentgenol 1990;155:855‑64. Senoglu M, Altun I. Lipoma of the quadrigeminal plate cistern. Internet J Radiol 2009;10:11. Yilmazlar S, Kocaeli H, Aksoy K. Quadrigeminal cistern lipoma. J Clin Neurosci 2005;12:596‑9. Ogbole G, Kazaure I, Anas I. Quadrigeminal plate cistern lipoma. BMJ Case Rep 2009; doi: 10.1136/bcr. 07.2009.2110. Yilmaz N, Unal O, Kiymaz N, Yilmaz C, Etlik O. Intracranial lipomas – A clinical study. Clin Neurol Neurosurg 2006;108:363‑8. Access this article online Quick Response Code
Website: www.neurologyindia.com DOI: 10.4103/0028-3886.158254 PMID: xxxxx
Hemifacial spasm associated with vertebral artery fenestration Sir, A 65‑year‑old woman presented with left hemifacial spasm (HFS) that had persisted for 4 years. Magnetic resonance angiography (MRA) demonstrated an elongated vertebral artery (VA) with a fenestration on the left side [Figure 1a]. Heavily T2‑weighted magnetic resonance images revealed a portion of the fenestration of the left VA
a
as a suspected offending vessel compressing the root exit zone (REZ) of the left facial nerve [Figure 1b]. The patient underwent microvascular decompression (MVD). A nerve bundle (a hypoglossal nerve) was observed passing through the fenestration [Figure 2a]. The medial portion of the VA fenestration compressed the REZ of the facial nerve, confirming the VA as an offending vessel [Figure 2]. The artery was displaced to the lateral‑caudal side with a Teflon felt and prosthesis was inserted between the VA fenestration and the cerebellum. As a result, the vessel was detached from the REZ securely [Figure 2b]. After operation, HFS disappeared, and no neurological deficits were detected. The arterial fenestrations usually do not have clinical significance, but in rare occasions may cause neurological symptoms or are associated with cerebral aneurysms, dissection, or arteriovenous malformation. [1] A recent large‑scale study using MRA demonstrated that fenestrations in all locations were found in 2.8% of the study population, and fenestration of the intracranial VA was found in 0.54%. In cases of VA‑associated HFS or HFS caused by sandwich‑type compression between posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA), the outcome of MVD is generally poor.[2] More difficult techniques are required for VA‑associated HFS because of the presence of arterial sclerosis, decreased mobility, anatomical variations like dolichoectatic VA, and perforator disturbance.[2] In the present case of HFS caused by fenestrated VA, careful investigation around the VA fenestration was necessary because unexpected perforators may arise from
b
Figure 1: (a) MRA demonstrating the vertebrobasilar system deviating to the left side with a left VA fenestration (arrow). (b) Thin-slice, heavily T2-weighted magnetic resonance images demonstrating a portion of the fenestrated VA attaching to the REZ of the left facial nerve (arrows)
Neurology India / May 2015 / Volume 63 / Issue 3
443
Copyright of Neurology India is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Copyright of Neurology India is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
