INTRAVENTRICULAR CNS LESIONS........pptx

INTRAVENTRICULAR CNS LESIONS........pptx

1. INTRAVENTRICULAR CNS LESIONS MODERATOR – DR. MANASA MDRD ASSISTANT PROFESSOR PRESENTER – DR. SWETHA

2. A variety of lesions may be identified in the ventricular system. Knowledge of the common location of certain lesions with presentation age together with typical imaging characteristics can significantly narrow the differential diagnosis

3. SUBEPENDYMOMA EPENDYMOMA SEBEPENDYMAL GIANT CELL ASTROCYTOMAS MENINGIOMAS CENTRAL NUROCYTOMA CHROID PLEXUS TUMOURS MEDULLOBLASTOMA METASTASIS

4. Subependymoma Subependymomas are rare, benign (WHO) grade I) Slow-growing Avascular tumors. Age group - middle-aged and elderly males. Location - fourth ventricle but can be located in the lateral ventricle (frontal horn and body). The majority are small (<2cm)

5. ON CT Well defined Lobulated Iso/hypoattenuating Possible calcification H emorrhage, and cystic change.

6. ON MRI T1 Iso to hypointense T2 Hyperintensity No enhancement

7. ON HPE Fine fibrillary background Tumor cells have uniform round and oval nuclei with an open chromatin arrangement

8. Ependymoma Supratentorial ependymomas are more frequently intraparenchymal in location , probably arising from embryonic rest cells Ependymomas (WHO grades II–III) account for 3–5% of intraventricular neoplasms. Age group - young patients Location - floor of fourth ventricle with the remaining arising from the lateral and third ventricles

9. They have a propensity for cerebrospinal fluid (CSF) spread , extending through the foramina of Luschka, Magendie or foramen magnum into the cerebellopontine angles and cisterna magna respectively. This feature is highly suggestive of an ependymoma.

10. On CT Hyperattenuating Heterogeneous secondary to calcification (in 50–80%) cystic components Haemorrhage may occur

11. ON MRI T1 iso/ hypointensity T2 hyperintensity heterogeneous contrast enhancement blooming on T2* weighted images if calcification or hemorrhage are present.

12. ON HPE Ependymomas are perivascular pseudorosettes and true ependymal rosettes.

13. Subependymal giant cell astrocytoma (SEGA) SEGAs (WHO grade I) 1–2% of all paediatric brain tumours 10–15% of patients with tuberous sclerosis (TS) and are the most common cerebral neoplasm in this condition. SEGAs are thought to arise from subependymal nodules (SENs). Age group – below 20 years Location – Foramen of monro

14. Subcortical tubers and SENs are common associated findings. Differentiation between SEGA and SEN The presence of hydrocephalus should define a lesion as a SEGA, regardless of its size, position or contrast enhancement Demonstration of growth on serial imaging.

15. On CT, iso/hypoattenuating masses that protrude into the ventricle Usually larger than 1 cm Calcifications are common Vivid contrast enhancement

16. On MRI, T1 iso/hypointense to gray matter T2 hyperintense or heterogeneous. Enhancement is vivid.

17. Meningioma Intraventricular meningiomas (WHO grades I–III ) One of the more common intraventricular neoplasms in the adult population Age group – middle aged ( F >M ) Location - manifest in the atria

18. ON CT circumscribed slightly hyperattenuating mass frequent foci of calcification (50%).

19. On MRI T1 and T2 isointense to grey matter Intense enhancement that is usually heterogeneous. Areas of cystic change and necrosis may be present.

20. Central neurocytoma Central neurocytomas are well-differentiated (WHO grade II) neoplasms arise from the septum pellucidum or lateral ventricular wall Age group - younger and middle-aged adults. Location - frontal horn or body of the lateral ventricle near the foramen of Monro.

21. On CT, Well defined Lobulated Hyperattenuating frequent foci of calcification (in >50%) Intratumoural cysts giving a bubbly appearance

22. On MRI Heterogeneous, usually T1 isointense to grey matter and T2 hyperintense. Prominent flow voids can be seen. Haemorrhage is rare Moderate to intense enhancement on postcontrast imaging

23. Choroid plexus tumors (CPTs) They are divided into Choroid plexus papilloma (CPP; grade I), Atypical CPP (WHO grade II) Choroid plexus carcinoma (CPC; WHO grade III) Age group - young children Location - atria of the lateral ventricles.

24. On CT, Lobulated Iso or mildly hyperattenuating Possible calcification and cystic change. Intense enhancement

25. On MRI, CPPs are homogeneously T1 iso/hypointense variable T2 signal intensity. They are vascular lesions that enhance vividly on post-contrast imaging . CPCs tend to be more heterogeneous because of necrosis, hemorrhage and cysts Surrounding parenchymal invasion and peritumoral oedema suggest CPC

26. Colloid cyst Location - Anterosuperior aspect of the third ventricle near the foramen of Monro. Age group – ( third to fifth decade) On CT Hyperattenuating with respect to the brain due to intrinsic elevated protein. Few millimetres to 3 cm

27. On MRI, Hyperintense on T1W Hypointense on T2W They may be difficult to detect on FLAIR if T2 hypointense. Intracystic fluid levels may be seen , Thin rim of enhancement may be present indicating the cyst capsule Calcifications are very rare

28. Medulloblastoma Medulloblastomas (WHO grade IV) Age group - children (males > females) Location – Posterior fossa This highly malignant neoplasm has a propensity to CSF spread. In children, they most frequently arise from the roof and project into the fourth ventricle. In adults, they arise in the cerebellar hemisphere.

29. On CT, well-circumscribed homogeneous hyperattenuating with enhancement demonstrate variable calcification and cyst formation

30. On MRI T1 hypointense to grey matter Variable appearance on T2-weighted sequences, but the solid component is typically iso to hyperintense. Heterogeneous enhancement after contrast is usual, Marginal vasogenic oedema is common.

31. Metastasis The atrium of the lateral ventricle is the most common site for intraventricular metastasis, followed by the third ventricle The most common primary tumours in children include neuroblastoma, retinoblastoma and Wilms’ tumour in adults, melanoma, renal, lung and colon carcinoma The imaging pattern is nonspecific and may mimic an intraventricular meningioma or CPP. T1 hyperintensity in melanoma Typically there is avid enhancement after contrast

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