Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

Brain Imaging in Colloid Cyst

  • Author: Andrew L Wagner, MD; Chief Editor: L Gill Naul, MD  more...
 
Updated: Oct 14, 2015
 

Overview

Colloid cysts are benign, congenital epithelium-lined cysts that almost always arise in the anterior third ventricle. However, rare reports describe cysts in other locations. The cysts are believed to derive from either primitive neuroepithelium of the tela choroidea or from endoderm.[1] See the images of colloid cysts below.

Sagittal nonenhanced T1-weighted magnetic resonanc Sagittal nonenhanced T1-weighted magnetic resonance image. This image demonstrates a round area of increased signal intensity in the anterosuperior portion of the third ventricle (arrow).
Axial fluid-attenuated inversion recovery magnetic Axial fluid-attenuated inversion recovery magnetic resonance image. This image shows a bright mass.
Axial contrast-enhanced T1-weighted magnetic reson Axial contrast-enhanced T1-weighted magnetic resonance image. This image demonstrates a small amount of peripheral enhancement but no discernible central enhancement. Note the location of the colloid cyst near the foramina of Monro.
Computed tomography scan in a 65-year-old man who Computed tomography scan in a 65-year-old man who had acute onset of headache. This image demonstrates a round area of increased attenuation at the foramina of Monro, with hydrocephalus. The image is degraded because of motion artifact, as the patient was in severe pain at the time of imaging.
Axial computed tomography scan in a 50-year-old ma Axial computed tomography scan in a 50-year-old man who was transported to the emergency department after falling down while lifting weights; he later had cardiopulmonary arrest. This image demonstrates a hyperattenuating colloid cyst at the foramina of Monro, with marked hydrocephalus.

The diagnosis is usually made by assessing the typical location and appearance of the cyst. Colloid cysts account for approximately 1% of all intracranial tumors and are the most common type of the neuroepithelial cysts, as well as the most common tumor in the third ventricle. Typically, patients are asymptomatic, although colloid cysts may cause symptoms by obstructing the foramen of Monro, which results in sudden death in rare cases.[2, 3]

Shapiro et al described the long-term results of an interhemispheric, transcallosal, subchoroidal, fornix-sparing approach to gross-total resection of colloid cysts. In 57 colloid cysts, total removal was achieved via a 3 x 3-in paramedian craniotomy flap and a microscopic interhemispheric, transcallosal, subchoroidal approach sparing the ipsilateral fornix. According to the investigators, at 1 year after surgery, computed tomography (CT) scanning or magnetic resonance imaging (MRI) confirmed gross-total resection, with no infection, hemiparesis, seizures, or disconnection syndrome. There were no deaths or recurrences. The authors noted that the results were superior to those seen with endoscopy.[4]

Preferred examination

Either CT scanning or MRI may help in diagnosing a colloid cyst, although MRI has a few advantages.[5, 6] The multiplanar capabilities of MRI optimally demonstrate the location of the cyst, and typical signal intensities in the cyst help to confirm the diagnosis. T2-weighted MRI sequences may be useful to assess the nature of the intracystic contents and to predict the difficulty of aspiration during endoscopic or stereotactic procedures.[7, 8, 9, 10, 11, 12, 13]

Typically, colloid cysts are clinically silent and are found incidentally when patients are imaged for other reasons. When patients are symptomatic, they typically experience chronic headaches, which may be intermittent and positional because of transient CSF obstruction. On rare occasions, a colloid cyst may completely and irreversibly obstruct the foramen of Monro, resulting in sudden loss of consciousness and, if patients are not treated, in coma and death.[2, 3]

Pollock et al reviewed 155 cases of colloid cyst and found 4 factors that were associated with colloid cyst-related clinical symptoms[14] : (1) younger patient age, (2) increased cyst size (average of 13 mm in symptomatic patients vs 8 mm in asymptomatic patients), (3) ventricular dilatation (although 31% of asymptomatic patients had this finding), and (4) increased signal intensity on T2-weighted MRIs. These findings suggest that slowly growing colloid cysts may allow for compensation by the brain, thus avoiding symptoms. In addition, findings of high T2 signals in symptomatic patients suggest that the more-serous colloid cysts enlarge the fastest.

The appearance of colloid cysts on CT and MRI scans is important in planning treatment, because the success rate after percutaneous aspiration is lower in colloid cysts that have high attenuation on CT scans and decreased MRI T2-signal intensity than in the cysts that have fluid characteristics.[15] Interestingly, the cysts with high T2-signal intensity are easier to treat with minimally invasive surgical techniques; however, these cysts are also the ones that are most likely to cause clinical symptoms.

Preferred examination

Although MRI has the advantage of multiplanar imaging, CT scanning is usually adequate for the diagnosis of a colloid cyst.

Limitations of techniques

Intraventricular hemorrhage occasionally mimics a colloid cyst on CT scans and MRI.

Subependymomas, central neurocytomas, and subependymal astrocytomas may occur in the same area as a colloid cyst on imaging studies, but these entities can be distinguished by their shape, contrast enhancement, and signal intensity.

Next

Computed Tomography

CT scan findings include a round mass with high attenuation at the anterior third ventricle. Rarely, colloid cysts may be isoattenuating or hypoattenuating relative to brain parenchyma. The typical high attenuation likely results from proteinaceous fluid. See the images below.

Computed tomography scan in a 65-year-old man who Computed tomography scan in a 65-year-old man who had acute onset of headache. This image demonstrates a round area of increased attenuation at the foramina of Monro, with hydrocephalus. The image is degraded because of motion artifact, as the patient was in severe pain at the time of imaging.
Axial computed tomography scan in a 50-year-old ma Axial computed tomography scan in a 50-year-old man who was transported to the emergency department after falling down while lifting weights; he later had cardiopulmonary arrest. This image demonstrates a hyperattenuating colloid cyst at the foramina of Monro, with marked hydrocephalus.

Hydrocephalus, which can be severe, results when the cyst obstructs the lateral ventricles at the foramen of Monro. This finding can be intermittent, as the cyst can act as a ball valve. Patients may then present with intermittent positional headaches.

Degree of confidence

A nonenhancing area of high attenuation in the typical location is almost diagnostic of a colloid cyst, but most clinicians confirm the diagnosis with MRI.

False positives/negatives

No normal variants are commonly confused with a colloid cyst.

Previous
Next

Magnetic Resonance Imaging

Colloid cysts are well demonstrated on MRI scans and are found near the foramen of Monro, just posterior to the fornices in the anterosuperior third ventricle. (See the images below.)

Sagittal nonenhanced T1-weighted magnetic resonanc Sagittal nonenhanced T1-weighted magnetic resonance image. This image demonstrates a round area of increased signal intensity in the anterosuperior portion of the third ventricle (arrow).
Axial fluid-attenuated inversion recovery magnetic Axial fluid-attenuated inversion recovery magnetic resonance image. This image shows a bright mass.
Axial contrast-enhanced T1-weighted magnetic reson Axial contrast-enhanced T1-weighted magnetic resonance image. This image demonstrates a small amount of peripheral enhancement but no discernible central enhancement. Note the location of the colloid cyst near the foramina of Monro.

The MRI signal intensity of colloid cysts is notoriously variable, with any combination of T1- and T2-signal intensities described.[5, 16, 17, 18, 19] The most common appearance is hyperintensity with T1-weighted sequences and isointensity to hypointensity with T2 sequences.[20] This variation is believed to be a result of the proteinaceous fluid, as well as the paramagnetic effects of the metal ions in the fluid and hemorrhage.

El Khoury et al found that low signal intensity of colloid cysts on T2-weighted images corresponded to difficult percutaneous aspiration in 100% of cases, whereas most of the cysts with high T2-signal intensity were considered easy to aspirate.[21]

Rarely, inspissated debris may form a dependent nodule that can be seen on CT and MRI scans.

Colloid cysts do not have intrinsic enhancement; the presence of enhancement suggests a solid tumor. Peripheral enhancement may be present because of vascularity in the outer wall.[20]

Degree of confidence

The diagnosis of a colloid cyst is made based on the classic location, appearance, and signal intensity. Central contrast enhancement suggests an alternative diagnosis, but most other pathologies that occur in this location are easily distinguishable from colloid cysts.

False positives/negatives

No normal variants are commonly confused with a colloid cyst.

Previous
 
Contributor Information and Disclosures
Author

Andrew L Wagner, MD Department of Radiology, Rockingham Memorial Hospital

Andrew L Wagner, MD is a member of the following medical societies: American College of Radiology, American Roentgen Ray Society, American Society of Neuroradiology, Radiological Society of North America

Disclosure: Nothing to disclose.

Specialty Editor Board

Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand

Disclosure: Nothing to disclose.

Chief Editor

L Gill Naul, MD Professor and Head, Department of Radiology, Texas A&M University College of Medicine; Chair, Department of Radiology, Baylor Scott and White Healthcare, Central Division

L Gill Naul, MD is a member of the following medical societies: American College of Radiology, American Medical Association, American Roentgen Ray Society, Radiological Society of North America

Disclosure: Nothing to disclose.

Additional Contributors

Lucien M Levy, MD, PhD 

Lucien M Levy, MD, PhD is a member of the following medical societies: American Cancer Society, American College of Radiology, American Heart Association, American Medical Association, American Roentgen Ray Society, American Society of Neuroradiology, Radiological Society of North America

Disclosure: Nothing to disclose.

References
  1. Lach B, Scheithauer BW, Gregor A, Wick MR. Colloid cyst of the third ventricle. A comparative immunohistochemical study of neuraxis cysts and choroid plexus epithelium. J Neurosurg. 1993 Jan. 78(1):101-11. [Medline].

  2. Shemie S, Jay V, Rutka J, Armstrong D. Acute obstructive hydrocephalus and sudden death in children. Ann Emerg Med. 1997 Apr. 29(4):524-8. [Medline].

  3. Stoodley MA, Nguyen TP, Robbins P. Familial fatal and near-fatal third ventricle colloid cysts. Aust N Z J Surg. 1999 Oct. 69(10):733-6. [Medline].

  4. Shapiro S, Rodgers R, Shah M, Fulkerson D, Campbell RL. Interhemispheric transcallosal subchoroidal fornix-sparing craniotomy for total resection of colloid cysts of the third ventricle. J Neurosurg. 2009 Jan. 110(1):112-5. [Medline].

  5. Maeder PP, Holtås SL, Basibüyük LN, et al. Colloid cysts of the third ventricle: correlation of MR and CT findings with histology and chemical analysis. AJNR Am J Neuroradiol. 1990 May. 11(3):575-81. [Medline].

  6. Mortimer AM, Bradley MD, Stoodley NG, Renowden SA. Thunderclap headache: diagnostic considerations and neuroimaging features. Clin Radiol. 2013 Mar. 68(3):e101-13. [Medline].

  7. Abdou MS, Cohen AR. Endoscopic treatment of colloid cysts of the third ventricle. Technical note and review of the literature. J Neurosurg. 1998 Dec. 89(6):1062-8. [Medline].

  8. Acerbi F, Rampini P, Egidi M, et al. Endoscopic treatment of colloid cysts of the third ventricle: long-term results in a series of 6 consecutive cases. J Neurosurg Sci. 2007 Jun. 51(2):53-60. [Medline].

  9. Grondin RT, Hader W, MacRae ME, Hamilton MG. Endoscopic versus microsurgical resection of third ventricle colloid cysts. Can J Neurol Sci. 2007 May. 34(2):197-207. [Medline].

  10. Horn EM, Feiz-Erfan I, Bristol RE, et al. Treatment options for third ventricular colloid cysts: comparison of open microsurgical versus endoscopic resection. Neurosurgery. 2007 Apr. 60(4):613-8; discussion 618-20. [Medline].

  11. Al-Hashel JY, Rady AA, Soliman DY, Vembu P. Diagnostic Dilemma in a Young Woman with Acute Headache: Delayed Diagnosis of Third Ventricular Colloid Cyst with Hydrocephalus. Case Rep Neurol Med. 2015. 2015:180404. [Medline].

  12. Niknejad HR, Samii A, Shen SH, Samii M. Huge familial colloid cyst of the third ventricle: An extraordinary presentation. Surg Neurol Int. 2015. 6 (Suppl 11):S349-53. [Medline].

  13. Bender B, Honegger JB, Beschorner R, Ernemann U, Horger M. MR imaging findings in colloid cysts of the sellar region: comparison with colloid cysts of the third ventricle and Rathke's cleft cysts. Acad Radiol. 2013 Nov. 20 (11):1457-65. [Medline].

  14. Pollock BE, Schreiner SA, Huston J 3rd. A theory on the natural history of colloid cysts of the third ventricle. Neurosurgery. 2000 May. 46(5):1077-81; discussion 1081-3. [Medline].

  15. Mathiesen T, Grane P, Lindgren L, Lindquist C. Third ventricle colloid cysts: a consecutive 12-year series. J Neurosurg. 1997 Jan. 86(1):5-12. [Medline].

  16. Mamourian AC, Cromwell LD, Harbaugh RE. Colloid cyst of the third ventricle: sometimes more conspicuous on CT than MR. AJNR Am J Neuroradiol. 1998 May. 19(5):875-8. [Medline]. [Full Text].

  17. Atlas SW, Lavi E. Intra-axial brain tumors. Atlas SW, ed. Magnetic Resonance Imaging of the Brain and Spine. 2nd ed. Philadelphia, Pa: Lippincott-Raven; 1996. 402-4.

  18. Scotti G, Scialfa G, Colombo N, Landoni L. MR in the diagnosis of colloid cysts of the third ventricle. AJNR Am J Neuroradiol. 1987 Mar-Apr. 8(2):370-2. [Medline].

  19. Sener RN. Colloid cyst: diffusion MR imaging findings. J Neuroimaging. 2007 Apr. 17(2):181-3. [Medline].

  20. Wilms G, Marchal G, Van Hecke P, et al. Colloid cysts of the third ventricle: MR findings. J Comput Assist Tomogr. 1990 Jul-Aug. 14(4):527-31. [Medline].

  21. El Khoury C, Brugières P, Decq P, et al. Colloid cysts of the third ventricle: are MR imaging patterns predictive of difficulty with percutaneous treatment?. AJNR Am J Neuroradiol. 2000 Mar. 21(3):489-92. [Medline]. [Full Text].

 
Previous
Next
 
Sagittal nonenhanced T1-weighted magnetic resonance image. This image demonstrates a round area of increased signal intensity in the anterosuperior portion of the third ventricle (arrow).
Axial fluid-attenuated inversion recovery magnetic resonance image. This image shows a bright mass.
Axial contrast-enhanced T1-weighted magnetic resonance image. This image demonstrates a small amount of peripheral enhancement but no discernible central enhancement. Note the location of the colloid cyst near the foramina of Monro.
Computed tomography scan in a 65-year-old man who had acute onset of headache. This image demonstrates a round area of increased attenuation at the foramina of Monro, with hydrocephalus. The image is degraded because of motion artifact, as the patient was in severe pain at the time of imaging.
Axial computed tomography scan in a 50-year-old man who was transported to the emergency department after falling down while lifting weights; he later had cardiopulmonary arrest. This image demonstrates a hyperattenuating colloid cyst at the foramina of Monro, with marked hydrocephalus.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.