CASE 1850 Published on 25.11.2002

Colloid cyst

Section

Neuroradiology

Case Type

Clinical Cases

Authors

B. Prokes, T. Nebesky, M. Mechl, V. Valek, R.N. Sener

Patient

62 years, male

Categories

No Area of Interest ; Imaging Technique CT, MR

No Procedure ; No Special Focus ;

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Clinical History

Acute onset of headaches.

Imaging Findings

The patient presented with acute onset of headaches. CT and MRI were performed revealing a small round mass lesion in the anterior third ventricle associated with hydrocephalus. The lesion was excised and histologically confirmed as a colloid cyst.

Discussion

Colloid cysts are most frequently and typically located in the anterosuperior region of the third ventricle. They are very rare congenital lesions considered to be derived from the primitive neuroepithelium. They may be asymptomatic (without hydrocephalus), may cause headaches (with hydrocephalus) or may cause acute onset headaches (with acute hydrocephalus). Fatal outcome has been reported in patients developing acute hydrocephalus and brain herniation.

On CT approximately two thirds of colloid cysts are hyperdense relative to the brain, and the remainder are isointense, while hypointense cysts on CT are rare. They appear relatively heterogeneous on MRI; however, the most common MRI appearance is that of a mass that is hyperintense on T1-weighted images and hypointense on T2-weighted images. On T2-weighted images a bright outer ring with a hypointense centre can be observed. In general, colloid cysts that appear hyperdense on CT and hyperintense on T1-weighted MR images usually correlate with high cholesterol content of the cyst. The cyst capsule may enhance as a thin rim after intravenous administration of paramagnetic contrast medium.

It has been reported that care should be exercised not to confuse CSF flow artefacts at the region of the foramina of Monro with colloid cysts, as these artefacts can mimic colloid cysts. On the other hand, it should be remembered that colloid cysts can very rarely be encountered in atypical locations such as the lateral ventricles, fourth ventricle, brain parenchyma, suprasellar region, and others. In this patient the colloid cyst was hyperdense on CT, it had a bright centre on T1-weighted MR imaging, which became markedly hypointense from proton-density to T2-weighted imaging, which corresponded to its high cholesterol content.

Differential Diagnosis List

Colloid cyst of the third ventricle

Final Diagnosis

Colloid cyst of the third ventricle

References

[1] Osborn AG. Diagnostic neuroradiology. Mosby, St Louis (1994).

[2] Maeder PP, Holtas SL, Basibuyuk LN, Salford LG, Tapper UA, Brun A. Colloid cysts of the third ventricle: correlation of MR and CT findings with histology and chemical analysis.
AJR Am J Roentgenol. 1990 Jul;155(1):135-41. (PMID: 2112837)

[3] Armao D, Castillo M, Chen H, Kwock L. Colloid cyst of the third ventricle: imaging-pathologic correlation.
AJNR Am J Neuroradiol. 2000 Sep;21(8):1470-7. (PMID: 11003281)

[4] Buttner A, Winkler PA, Eisenmenger W, Weis S. Colloid cysts of the third ventricle with fatal outcome: a report of two cases and review of the literature.
Int J Legal Med. 1997;110(5):260-6. (PMID: 9297582)

[5] Sener RN, Jinkins JR. CT of intrasellar colloid cyst. J Comput Assist Tomogr. 1991 Jul-Aug;15(4):671-2. (PMID: 2061486)

Case information

URL:	https://www.eurorad.org/case/1850
DOI:	10.1594/EURORAD/CASE.1850
ISSN:	1563-4086

Figure 1

Colloid cyst

CT scan reveals the hyperdense mass located at the anterosuperior region of the third ventricle, typical of a colloid cyst. Note hydrocephalus.

Figure 2

Colloid cyst

T1-weighted image reveals a hyperintense centre with an isointense rim. Note hydrocephalus.

Coronal, proton-density-weighted image reveals low signal in the centre surrounded by a hyperintense rim, the opposite of the appearance on the T1-weighted image. Note hydrocephalus.