This document describes and shows images of 12 different types of intraventricular masses: 1. Choroid plexus papilloma 2. Colloid cyst 3. Intraventricular meningioma 4. Ependymoma 5. Giant cell astrocytoma 6. Dermoid cyst 7. Epidermoid tumor 8. Primitive neuroectodermal tumor 9. Malignant teratoma 10. Oligodendroglioma 11. Neurocytoma 12. Hemorrhagic metastatic melanoma Each mass is described and an MR or CT image shows the location and features of each type of intraventricular mass.

1. 23Intraventricular Masses

2. CLINICAL IMAGAGING
AN ATLAS OF DIFFERENTIAL DAIGNOSIS
EISENBERG
DR. Muhammad Bin Zulfiqar
PGR-FCPS III SIMS/SHL

3. • Fig SK 23-1 Choroid plexus papilloma. T1-weighted
coronal image shows a lobulated isointense mass
(arrows) in a markedly dilated right lateral ventricle.

4. • Fig SK 23-2 Colloid cyst. T1-weighted coronal MR
scan shows a hyperintense mass in the third
ventricle just posterior to the foramen of Monro.
There is ventricular dilatation in this elderly man
with a history of recurrent headache.27

5. • Fig SK 23-3 Intraventricular meningioma. Well-
circumscribed mass (arrow) in the posterior aspect of the
left lateral ventricle in a patient with neurofibromatosis

6. • Fig SK 23-4 Ependymoma. Large intraventricular mass (arrows)
located in the third ventricle and anterior horns of both lateral
ventricles; there is associated hydrocephalus. Areas of greatest
hyperintensity in the tumor represent subacute hemorrhage.34

7. • Fig SK 23-5 Giant cell astrocytoma. (A) Contrast-enhanced T1-
weighted MR image shows a markedly hyperintense intraventricular
mass (arrowhead) in this young boy with clinical stigmata of
tuberous sclerosis. (B) T2-weighted image at another level shows
characteristic high-signal cortical hamartomas (arrows) as well as
dense calcifications (arrowheads).35

8. • Fig SK 23-6 Dermoid cyst. Coronal T1-weighted
MR image shows a hyperintense mass
(arrows) filling the dilated right temporal horn.
The lateral and third ventricles are enlarged.36

9. • Fig SK 23-7 Epidermoid tumor. Sagittal T-weighted MR image shows a large
mass filling the fourth ventricle. The mass has a slightly higher signal
intensity than CSF. It depresses the brainstem (black arrows) and elevates
the tonsil and inferior vermis (white arrows).

10. • Fig SK 23-8 Primitive neuroectodermal tumor. (A)
Sagittal T1-weighted MR image shows a large,
inhomogeneously isointense mass (arrows) filling
the entire body of the left lateral ventricle and
compressing the third ventricle, midbrain, and
upper vermis of the cerebellum. (B) Coronal T1-
weighted scan demonstrates intense
enhancement of the lesion.36

11. • SK 23-9 Malignant teratoma. (A) Coronal T1-
weighted MR image shows a large, irregular,
lobulated mass (arrows) of inhomogeneous
hypointensity in the body and occipital horn of
the left lateral ventricle. (B) On the axial
proton-density-weighted image, the mass is
hyperintense (arrows).36

12. • Fig SK 23-10 Oligodendroglioma. Axial T1-weighted MR
image shows a large lobulated isointense mass (arrows)
with cystic components (arrowheads) involving the septum
pellucidum and bodies of the lateral ventricles.36

13. • Fig SK 23-11 Neurocytoma. (A) Axial T2-weighted
MR image shows the heterogeneous appearance
of the lesion, reflecting the presence of cystic
spaces and calcifications. (B) CT scan shows
coarse, conglomerate calcification and large cystic
areas within the intraventricular tumor.37

14. • Fig SK 23-12 Hemorrhagic metastatic melanoma. Sagittal T1-weighted MR
image shows a round mass filling the left frontal horn near the foramen of
Monro. The mass has a hyperintense rim (arrows), most likely
representing methemoglobin, and a hypointense center (arrowheads).36