Intracranial Cysts and Cystic Lesions: ASN Annual Meeting 2016

1. Intracranial Cysts and Cystic Lesions:ASN Annual Meeting 2016 John A. Bertelson, MD Chief of Neurology, Seton Brain and Spine Institute Assistant Professor of Medicine, Dell Medical School, UT Austin Clinical Assistant Professor of Psychology, UT Austin

2. Relevant Disclosures • None

3. Thanks • BelaAjtai, MD PhD

4. Outline Why? Location-Based Cysts Intra-axial vs. Extra-axial Midline vs. Non-midline Intra-Ventricular vs. Extra-Ventricular Sample Cases

5. Why Review Intracranial Cysts?

6. Why Review Intracranial Cysts? Extremely common incidental findings Need to exclude pathologic lesions Generate a focused differential based on cyst location and imaging appearance

7. Intracranial Cysts • Intra-Axial • Parenchymal • Intraventricular • Extra-Axial • Midline • Non-midline

8. Intra-Axial Cysts Parenchymal Intra/peri-ventricular Choroid Fissure Cyst Choroid Plexus Cysts Ependymal Cyst Colloid Cyst Septum Pellucidum Cavum Septum Pellucidum CavumVergae Cavum Vellum Interpositum • Virchow-Robin Spaces • Neuroglial Cyst • Hippocampal Sulcal Remnant Cysts

9. Intracranial Cysts • Intra-Axial • Parenchymal • Intraventricular • Extra-Axial • Midline • Non-midline

10. Dilated Virchow-Robin Spaces • Aka Enlarged Perivascular Spaces • Histopathology • Pial-lined interstitial fluid filled structures • Single or double layers of invaginatedpia • Accompany penetrating arteries and veins • Location • Commonly seen in basal ganglia • Also found in midbrain, deep white matter, other structures • When found diffusely, designated Etatcriblé

11. Dilated Virchow-Robin Spaces • Imaging Characteristics • Usually < 5mm diameter • Often clustered • Isointense to CSF • 25% have a rim of slightly increased T2W signal intensity Ajtai and Bertelson, In Press

12. Dilated Virchow-Robin Spaces Ajtai and Bertelson, In Press

13. Neuro-Glial Cysts Osborn 2006 Ajtai and Bertelson, In Press • Aka glioependymal cyst • Histopathology • Congenital • From embryonic neural tube • Epithelial-lined cyst • Imaging • Smooth, rounded cystic lesion • Nonenhancing • CSF isointense • No pericystic abnormality • Anywhere in neuro-axis

14. Neuro-Glial Cysts Ajtai and Bertelson, In Press

15. Hippocampal SulcalRemnant Cysts • Aka Hippocampal sulcus remnant cavities • Histopathology • Remnants of the primitive hippocampal sulcus • Usually obliterated in normal development • Not associated with Alzheimer’s disease Ajtai and Bertelson, In Press

16. Intracranial Cysts • Intra-Axial • Parenchymal • Intraventricular • Extra-Axial • Midline • Non-midline

17. Choroid Fissure Cyst • Histopathology • Choroid Fissure: • Part of the medial wall of the lateral ventricle • Between the fimbria of hippocampus and diencephalon • Arachnoid cyst or neuro-epithelial cyst • Imaging: • Isointense to CSF on all sequences • Non enhancing

18. Choroid Fissure Cyst Ajtai and Bertelson, In Press

19. Choroid Fissure Cyst http://ultimate-radiology.blogspot.com/2015/12/choroid-fissure-cyst.html

20. Choroid Plexus Cysts • Histopathology • Epithelial lined cysts of choroid plexus • Contain nests of foamy, lipid-laden, histiocytes • May also be nodular or partially cystic • Most commonly found in bodies of lateral ventricles • May also occur in 3rd ventricle • Most common intracranial cyst (<50% of autopsies) • Usually bilateral, 2-8mm in diameter • Rarely > 2cm

21. Choroid Plexus Cysts • Imaging Characteristics • MRI • T1W iso to ↑-intense • T2W ↑-intense • DWI usually restricted diffusion • CT • Often calcified Osborn 2006

22. Choroid Plexus Cysts Ajtai and Bertelson, In Press

23. Ependymal Cyst • Histopathology • Ependymal lined cysts of lateral ventricle • Rare, benign • Imaging • Thin walled • CSF signal • Non-enhancing Ajtai and Bertelson, In Press

24. Colloid Cyst • Histopathology • Congenital, arising from ectopic embryonic endoderm • Mucin-containing cysts • Intraventricular • 15-20% of intraventricular masses • Almost always occur at the foramen of Monro • Variable size (0.3-4cm, mean 1.5cm) • Clinical relevance • May produce acute hydrocephalus Osborn 2006

25. Colloid Cyst Ajtai and Bertelson, In Press

26. Septum Pellucidum • Anatomy • Thin plate extending from corpus callosum to Fornix • 1.5-3mm thick • Contains glial cells, neurons, vasculature, ependyma • Associated Disorders (agenesis) • Holoprosencephaly • Septooptic dysplasia • Apert syndrome Sarwar 1989

27. Cavum Septum Pellucidum (CSP)Cavum Septum Vergae Cavum Septum Pellucidum Cavum Septum Vergae Lack of fusion of the paired septal walls posteriorly May cause downward displacement of the fornix Often seen in conjunction with CSP • Lack of fusion of the paired septal walls anteriorly • May be associated with • TBI • Schizophrenia

28. Cavum Septum Pellucidum (CSP)Cavum Septum Vergae Cavum Septum Pellucidum CSP and Cavum Septum Vergae Ajtai and Bertelson, In Press

29. CavumVeliInterpositum (CVI) CVI • Located below the fornix • Formed by separation of the telachoroidea • Usually asymptomatic, rarely large enough to exert mass effect on adjacent structures Ajtai and Bertelson, In Press

30. CavumVeliInterpositum (CVI) Ajtai and Bertelson, In Press

31. Extra-Axial Cysts Midline Non-Midline Epidermoid * Arachnoid Cyst * • Dermoid • Pineal cyst * Can occur midline or non-midline

32. Intracranial Cysts • Intra-Axial • Parenchymal • Intraventricular • Extra-Axial • Midline • Non-midline

33. Dermoid Cyst • Histopathology • Ectodermal inclusion cysts • Contain epidermal cells and dermally-derived cells • Usually found extra-axial, midline • Rarely have intra-axial locations • Imaging characteristics • T1W hyperintense (lipids) • T2W heterogeneous • Nonenhancing • unless recently ruptured, due to chemical meningitis

34. Dermoid Cyst

35. Pineal Cysts • Histopathology • Cysts or cystic degeneration of pineal gland • Uni- or multi-locular • Multiple theories as to origin • Most < 1cm diameter • Clinical Relevance • Usually none • Larger cysts may cause hydrocephalus or Parinaud phenomenon

36. Other Pineal Lesions • DDx • Pineocytoma • Often have solid component • Can be very difficult to distinguish from pineal cyst • Pineoblastoma • Arachnoid cyst • Astrocytoma • Epidermoid

37. Pineal Cyst 21 of 51 Ajtai and Bertelson, In Press

38. Intracranial Cysts • Intra-Axial • Parenchymal • Intraventricular • Extra-Axial • Midline • Non-midline

39. Epidermoid Cysts • Histopathology • Congenital inclusion cysts • Usually develop during neural tube closure, rarely due to trauma • Most commonly located in cerebellopontine angle cistern • Less often found in 4th ventricle or sella/parasellar regions • Clinical relevance • Up to 2% of primary intracranial tumors • 4-9 times as common as dermoidcysts • Usually asymptomatic • May cause cranial neuropathies due to engulfing these nerves • Occasionally rupture, causing granulomatous meningitis

40. Epidermoid Cysts • MRI appearance • T1W/T2W: • slightly ↑–intense to CSF • DWI: • restricted diffusion • Nonenhancing Osborn 2006

41. Arachnoid Cysts • Histopathology • Intra-arachnoid • Benign, congenital lesions filled with CSF • Usually supratentorial, • 50-60% within the middle cranial fossa • Clinical relevance • Generally asymptomatic • Displaces (does not engulf) cranial nerves • Rarely result in cranial neuropathies Osborn 2006

42. Arachnoid Cysts • MRI appearance • Iso–intense to CSF on T1, T2, FLAIR • DWI normal • Nonenhancing • May cause “scalloping” of adjacent calvarium Ajtai and Bertelson, In Press

43. Arachnoid Cyst Ajtai and Bertelson, In Press

44. Pathologic Processes withCystic Components • Neoplasm • GlioblastomaMultiforme • Metastasis • Hemangioblastoma • Infection • Abscess • Neurocysticercosis • Other • Porencephalic Cysts

45. Porencephalic Cyst Acquired cavities of CSF Traumatic, vascular, or infectious insult Variable size Usually lined by gliotic white matter

46. Porencephalic Cyst Ajtai and Bertelson, In Press

47. Neurocysticercosis (NCC) Acquired cystic disorder due to infection by parasite T. solium Common cause of epilepsy in endemic regions Brutto, 2012

48. Life Cycle of T. solium Brutto, 2012

49. Stages of NCC Ajtai and Bertelson, In Press

50. Vesicular (scolex) Stage of NCC Brutto, 2012