neurology tumors cysts and disesaes partb 1

A brain tumor is a growth of cells in the brain or near it. Brain tumors can happen in the brain tissue. Brain tumors also can happen near the brain tissue. Nearby locations include nerves, the pituitary gland, the pineal gland, and the membranes that cover the surface of the brain.

Brain tumors can begin in the brain. These are called primary brain tumors. Sometimes, cancer spreads to the brain from other parts of the body. These tumors are secondary brain tumors, also called metastatic brain tumors.

Many different types of primary brain tumors exist. Some brain tumors aren't cancerous. These are called noncancerous brain tumors or benign brain tumors. Noncancerous brain tumors may grow over time and press on the brain tissue. Other brain tumors are brain cancers, also called malignant brain tumors. Brain cancers may grow quickly. The cancer cells can invade and destroy the brain tissue.

Brain tumors range in size from very small to very large. Some brain tumors are found when they are very small because they cause symptoms that you notice right away. Other brain tumors grow very large before they're found. Some parts of the brain are less active than others. If a brain tumor starts in a part of the brain that's less active, it might not cause symptoms right away. The brain tumor size could become quite large before the tumor is detected.

Brain tumor treatment options depend on the type of brain tumor you have, as well as its size and location. Common treatments include surgery and radiation therapy.

Types
There are many types of brain tumors. The type of brain tumor is based on the kind of cells that make up the tumor. Special lab tests on the tumor cells can give information about the cells. Your health care team uses this information to figure out the type of brain tumor.

Some types of brain tumors usually aren't cancerous. These are called noncancerous brain tumors or benign brain tumors. Some types of brain tumors usually are cancerous. These types are called brain cancers or malignant brain tumors. Some brain tumor types can be benign or malignant.

Benign brain tumors tend to be slow-growing brain tumors. Malignant brain tumors tend to be fast-growing brain tumors.

Glioblastoma brain tumor
Glioblastoma
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Child with a medulloblastoma brain tumor
Medulloblastoma
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Acoustic neuroma, a benign tumor on the nerves leading from the inner ear to the brain
Acoustic neuroma (vestibular schwannoma)
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Types of brain tumors include:

Gliomas and related brain tumors. Gliomas are growths of cells that look like glial cells. The glial cells surround and support nerve cells in the brain tissue. Types of gliomas and related brain tumors include astrocytoma, glioblastoma, oligodendroglioma and ependymoma. Gliomas can be benign, but most are malignant. Glioblastoma is the most common type of malignant brain tumor.
Choroid plexus tumors. Choroid plexus tumors start in cells that make the fluid that surrounds the bra

1. Neurology- neoplasms, tumours and cysts 1 DR.SHIVANGI LAHOTY

2. The WHO CNS5 groups of tumours (as published in 2021) 1. Gliomas, glioneuronal and neuronal tumours 2. Choroid plexus tumours 3. Embryonal tumours 4. Pineal tumours 5. Cranial and paraspinal nerve tumours 6. Meningiomas 7. Mesenchymal, non-meningothelial tumours involving the CNS 8. Melanocytic tumours 9. Haematolymphoid tumours involving the CNS 10. Germ cell tumours 11. Tumours of the sellar region 12. Metastases to the CNS 13. Genetic tumour syndromes involving the CNS

3. WHO CNS5 classification of gliomas, glioneuronal and neuronal tumours Adult-type diffuse gliomas - Astrocytoma, IDH-mutant - Oligodendroglioma, IDH-mutant and 1p/19q-codeleted - Glioblastoma, IDH- wild type Paediatric-type diffuse low-grade gliomas - Diffuse astrocytoma - Polymorphous low-grade neuroepithelial tumour of the young

4. Paediatric-type diffuse high-grade gliomas - Diffuse midline glioma, H3 K27-altered Circumscribed astrocytic gliomas - Pilocytic astrocytoma - Pleomorphic xanthoastrocytoma - Subependymal giant cell astrocytoma Glioneuronal and neuronal tumours - Ganglioglioma - Desmoplastic infantile ganglioglioma/desmoplastic infantile astrocytoma - Gangliocytoma Ependymoma

5. G liomas are the most common type of primary brain tumor in adults. Since 2021, molecular data including IDH1/2 mutation and 1p/19q chromosomal co-deletion status are considered with, and usually supersede, histological phenotype to form integrated pathological diagnoses of diffuse glioma subtypes.

6. IDH – WILD TYPE DIFFUSE GLIOMAS IDH-wildtype diffuse gliomas are most commonly diagnosed as glioblastoma , WHO grade 4. IDH-wildtype glioblastomas occur mostly in the elderly. On MRI, IDH-wildtype glioblastomas typically have heterogeneous enhancement with surrounding non enhancing T2 prolongation. The enhancing component and sometimes the non-enhancing infiltrative component can exhibit diffusion restriction (dark ADC) on diffusion-weighted imaging due to hypercellularity, and elevated blood volume on perfusion-weighted imaging, indicating hypervascularity.

7. Glioblastoma with MR perfusion: Axial post-contrast T1-weighted (left image) and T2-weighted (middle image) MRI show a heterogeneous enhancing mass with central necrosis and surrounding edema in the left parietal lobe. There is associated mildly elevated CBV in the non-necrotic peripheral components

8. MRS Choline peak: The choline peak is increased in GBM, and the increase is more pronounced in higher grade gliomas. N-acetyl aspartate (NAA) peak: The NAA peak is decreased in GBM. Choline/NAA ratio >2.2 is suggestive of high grade glioma. Lipid lactate peak is also seen in GBM.

9. IDH-mutant diffuse gliomas These are divided into astrocytic and oligodendroglial subtypes based on 1p19q chromosomal co-deletion. 1p19q non-co-deleted IDH-mutant tumors are more common and include astrocytomas .1p19q co-deleted IDH-mutant tumors are less common and include oligodendrogliomas. IDH-mutant diffuse gliomas occur mostly in young to middle-aged adults (20–55 years).

10. Lower-grade astrocytomas typically appear as a circumscribed hyperintense mass on T2-weighted images. The T2- FLAIR mismatch sign is highly specific for astrocytomas: hyperintense on T2-weighted images but relatively centrally hypointense on FLAIR due to microcystic changes. Lower-grade oligodendrogliomas typically appear as a poorly circumscribed hyperintense mass on T2-weighted images. They are most often found in the frontal and temporal cortical regions and the majority calcify. An expansile, cortical-based mass with gyriform calcification is specific for oligodendroglioma. It doesn’t show T2 FLAIR MISMATCH. MYOINOSITOL PEAK is a feature of low grade gliomas on MRS.

11. A strocytoma: Axial FLAIR image shows a region of hyperintensity in the left occipital white matter and cortex (arrows). A strocytoma in a different patient: Axial post-contrast T1-weighted MRI shows a well defined enhancing lesion in the right temporal lobe (arrow).

12. T2 FLAIR MISMATCH

13. Oligodendroglioma: MRI (left image) demonstrates a hyperintense, expansile, cortically based mass centered in the right precentral gyrus. Axial non contrast CT (right image) shows the mass is partially calcified .

14. Diffuse midline glioma, H3 K27M-mutant Diffuse midline gliomas typically appear as an expansile, solid or infiltrative mass in the brainstem that is hypointense on T1,hyperintense on T2-FLAIR. Contrast enhancement is variable.

15. Diffuse brainstem glioma: Axial and sagittal FLAIR images demonstrate an expansile, T2 hyperintense mass centered in the pons with involvement of the entire brainstem, cerebellar peduncles, and bilateral cerebellar hemispheres.

16. Pleomorphic xanthoastrocytoma (PXA) PXAs usually present in children or young adults. On MRI, it presents as a cyst with mural nodule on meningeal side which enhances on post contrast imaging. Associated with BRAF V600E mutation.

17. Axial T2WI showing the iso-intense mural nodule and the homogeneously hyper-intense cystic component. (B) Contrast-enhanced axial T1WI showing marked enhancement of the mural nodule and cystic wall. (C) DWI showing restricted diffusion of the mural nodule. (D) The mean ADC ratio was 1.08. (E) Photomicrography of the tumor showing marked cellular pleomorphism, with spindle cells, multi-nucleated giant cells with bizarre nuclei, and lipid-filled xanthomatous cells (F) Molecular detection showing the BRAFV600E mutation.

18. Dysembryoplastic neuroepithelial tumor (DNET) DNETs usually present in children or young adults. On CT, DNET appears hypodense and occasionally calcifies. On MRI, DNETs show a circumscribed bubbly appearance The tumor can be heterogeneous and shows no enhancement.

19. Ganglioglioma Gangliogliomas usually present in children or young adults. The imaging appearance is variable. A common appearance is a circumscribed cystic mass with enhancing mural nodule without meningeal component. T2W TIW FAT SAT POST CONTRAST

20. Desmoplastic infantile ganglioneuroma (DIG) DIG is classified together as WHO grade 1 glial/glioneuronal tumors. They present in infants usually with progressive head enlargement. On MRI, DIG characteristically appears as a large multicystic and solid mass (cysts with mural nodule) . The solid component enhances avidly.

21. Hemangioblastoma Hemangioblastoma is a highly vascular WHO grade 1 tumor that is the most common primary brain neoplasm in the posterior fossa in adults (AGE > 20 YRS). Hemangioblastoma occurs most commonly in the cerebellum, followed by spinal cord, brainstem, and retina. It only rarely occurs supratentorially. The classic appearance of hemangioblastoma is a cystic mass with an avidly enhancing mural nodule . Less commonly, a hemangioblastoma may be solid or hemorrhagic.

22. Pilocytic astrocytoma / juvenile pilocytic astrocytoma (JPA) Pilocytic astrocytoma, is a WHO grade 1 astrocytic tumor. JPAs are well-circumscribed and is the most common benign brain tumor of childhood (0-20 YRS). The majority occur in the cerebellum. MRI typically shows a cystic mass with an avidly enhancing nodule and relatively little edema. A more aggressive variant is the pilomyxoid astrocytoma, which is not distinguishable on imaging but tends to involve optic chiasm/hypothalamus in younger children and infants.

23. Ependymoma Ependymoma arises from the ependymal lining of the floor of ventricular system and central canal of the spinal cord. Ependymoma tends to occur in the posterior fossa in children. In adults, ependymomas occur more commonly in the spinal cord and supratentorium. On imaging, ependymomas appear as an enhancing mass with heterogeneity related to cystic/necrotic change, calcification, or hemorrhage. On MRS, raised choline peak and reduced NAA peak is seen in addition to raised myoinositol peak. The posterior fossa ependymoma has been called the toothpaste or plastic tumor for its propensity to fill the fourth ventricle and squeeze through the foramina of Magendie or Luschka into the adjacent basal cisterns.

24. Ependymoma: Precontrast T1-weighted (left image) and post-contrast T1-weighted sagittal MRI (right image) shows a lobulated, isointense, avidly enhancing mass arising from the fourth ventricle (arrows).

25. Axial Flair and contrast-enhanced T1-Weighted images: a predominantly solid lesion that arises from the fourth ventricle and extends through the foramen of Luschka into the right cerebellopontine angle.

26. Medulloblastoma Medulloblastoma is the most common brain malignancy of childhood. Medulloblastoma is slightly hyperattenuating on CT, hypointense on T2-weighted images and has low ADC values( shows diffusion restriction) . The tumor enhances and may appear heterogeneous due to internal hemorrhage and calcification. Leptomeningeal metastatic disease is present in up to 1/3 of patients and medulloblastoma is the most common cause of drop metastases to the spine in children. In this setting, sugar-coating (Zuckerguss) refers to the icing-like enhancement over the brain and spinal cord surface. Imaging of the entire brain and spine should be performed prior to surgery. MRS shows choline and lactate peak. Taurine peak is specific.

27. Axial unenhanced CT shows a hyperdense mass in the midline posterior fossa (arrows). There is near complete effacement of the fourth ventricle, with resultant hydrocephalus. Post-contrast T1-weighted MRI shows the avidly enhancing mass (yellow arrows) completely effacing the fourth ventricle. There is enhancing leptomeningeal tumor dissemination within the internal auditory canals bilaterally (green arrows).

28. Dysplastic cerebellar gangliocytoma (Lhermitte-Duclos) Dysplastic gangliocytoma of the cerebellum, more often known as Lhermitte-Duclos disease, is a WHO grade 1 neuronal lesion that has been considered a hamartoma by some and neoplasm by others. The characteristic imaging finding is a tiger-striped appearance of thickened folia in the cerebellar hemisphere. The lesion is hyperintense on T2-weighted images and enhancement is rare. It is associated with Cowden syndrome.

29. MENINGIOMA Most common non glial primary brain tumor. Occurs around 30-60 yrs of age Female preponderance Appears as an extra axial dura based lesion mostly supratentorial in location.

30. Radiological findings CT appearance: On unenhanced scan meningioma usually appear as homogenous high density mass with rounded well defined margins -Calcifications are found in 16-20% of cases -Marked & uniform enhancement post Contrast with spoke wheel pattern due to raised vascularity MRI: TI & T2 hypointense Shows diffusion restriction Diffuse post contrast enhancement MRS: Alanine peak is seen.

31. A well-defined lobulated extra-axial large vividly-enhancing mass lesion with a broad-based dural tail, and radiating dural-based vessels giving a sunburst appearance is seen on post contrast fat sat TIW MRI.

32. LYMPHOMAS Lymphomas of the central nervous system, the most common of which is primary diffuse large B-cell lymphoma of the CNS, are the second most common primary brain tumour after gliomas. Primary CNS lymphomas present as solitary (60-70%) or multiple (30-40%) lesions with a predilection for the periventricular white matter , although they can also arise in the cortex or deep grey matter. Although leptomeningeal and ependymal deposits are common, if no substantial parenchymal mass is present, then secondary lymphoma should be favoured. Crossing of the corpus callosum fairly common and a helpful feature.

33. Radiographic features CT Most primary CNS lymphomas are hyperattenuating Show enhancement Haemorrhage is distinctly uncommon Often multiple lesions in patients with HIV/AIDS

34. MRI T1: typically hypointense to grey matter T2: hypointense to grey matter T1 C+ (Gd):intense homogeneous enhancement is most common peripheral ring enhancement may be seen in 10-15% of cases (especially in immunocompromised patients) DWI/ADC :restricted diffusion with ADC values lower than a normal brain MR spectroscopy:large choline peak reversed choline/ creatine ratio markedly decreased NAA lactate peak may also be seen

35. Left periventricular mass demonstrating a homogeneous, T2 iso- to hyperintense mass with patchy enhancement post gadolinium and prominent restricted diffusion.

36. MR spectroscopy reveals significant elevation of choline and reduction of NAA and creatine levels in the areas of enhancement. In addition there is significantly raised choline/creatine ratio of with elevated lipid/lactate.

37. MR perfusion No significant increment in CBV. Higher percentage signal recovery (PSR) in DSC perfusion with typical "overshoot" (PSR>100%) Axial contrast-enhanced T1 weighted image shows a thick irregular rim enhancing mass at the left basal ganglion. (B) DSC perfusion reveals mild hyperperfusion with return of timesignal intensity curve above the baseline after initial drop (arrow).

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