neurology neoplasm tumors and cysts part 2

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 2 DR.SHIVANGI LAHOTY

2. Pineal region masses

3. Overview and anatomy of the pineal region

4. Germ cell tumors The most common site of intracranial germ cell tumors is the pineal gland, followed by the suprasellar region. Intracranial germ cell tumors have a peak incidence in the teenage years. Pineal region germ cell tumors in particular have a male predominance. Germinoma is a highly cellular, avidly enhancing tumor that is slightly hyperdense on CT, isointense on T1- and T2-weighted images, and is dark on ADC map. Germinoma characteristically “engulfs” the pineal gland and promotes its calcification, resulting in central area of calcification. Teratoma has a heterogeneous imaging appearance. Intralesional fat is suggestive of teratoma . Teratoma is prone to hemorrhage and coarse calcification

5. Pineal germinoma: Axial CT shows a homogeneously enhancing pineal mass lesion engulfing Pineal calcification. In MRI, the mass is isointense on T2-weighted image(T2WI)(B)and shows restricted diffusion.

6. Pineal region teratoma: Sagittal noncontrast CT (left image) and axial T1-weighted MRI (right image) show a fat-containing mass in the pineal region (arrows). There is associated obstructive hydrocephalus due to compression of the cerebral aqueduct by the mass.

7. Pineal parenchymal tumors Pineal parenchymal tumors are a spectrum including pineocytoma (WHO grade 1), pineal parenchymal tumor of intermediate differentiation (grade 2 or 3), and pineoblastoma (grade 4). Pineoblastomas affect young children whereas the other pineal parenchymal tumors are mostly seen in adults. Any solid component of a pineal parenchymal tumor should demonstrate enhancement. Cystic change or necrosis is common, which can make it difficult to differentiate from a pineal cyst. Higher grade tumors are associated with ill-defined margins (invading adjacent structures), more restricted diffusion owing to high cellularity, and a propensity for CSF seeding. Germ cell tumors “engulf” by inducing calcification of the pineal gland, whereas pineal parenchymal tumors "explode" by peripherally displacing existing physiologic pineal calcifications.

8. Pineal parenchymal tumor of intermediate differentiation: Axial noncontrast CT (left image) demonstrates a hyperdense pineal mass. Post-contrast T1-weighted MRI (right image) shows the mass enhances.

9. Pineocytoma: Sagittal (A) and axial (B) T2-weighted image (T2WI) shows a well-defined mass Lesion in pineal region with cystic areas .The mass enhances intensely with contrast administration.

10. Pineal cyst Contrast is necessary when evaluating a pineal cyst, as the primary differential diagnosis is a pineal parenchymal tumor. Pineal cysts may show thin, smooth peripheral enhancement but not thick, irregular, or nodular enhancement

11. Intraventricular tumors

12. Central neurocytoma Central neurocytoma is a WHO grade 2 neuronal tumor that occurs in young adults. The most common location is the anterior part of the lateral ventricle near the foramen of Monro, sometimes extending into the third ventricle. Typical imaging findings are a heterogeneous, multicystic ( bubbly or Swiss cheese appearing ), lobulated, moderately enhancing mass attached to the septum pellucidum. Calcification is common.

13. Subependymal giant cell astrocytoma (SEGA) Subependymal giant cell astrocytoma (SEGA) is a benign (WHO grade 1) astrocytoma variant that is associated with tuberous sclerosis complex. Other common intracranial findings in tuberous sclerosis include subependymal nodules (hamartomas), cortical/subcortical tubers, and white matter radial bands. SEGA classically is an enhancing, heterogeneous mass in the lateral ventricle near the foramen of Monro. SEGA is distinguished from subependymal nodule by serial growth or size >1 cm.

14. Choroid plexus tumors Choroid plexus tumors consist of choroid plexus papilloma (WHO grade 1), atypical choroid plexus papilloma (grade 2), and choroid plexus carcinoma (grade 3). In children, the lateral ventricle is the most common location. In adults, the fourth ventricle is the most common location. The characteristic appearance on MRI is a cauliflower-like intraventricular mass that avidly enhances. Higher grade is associated with larger size and more extensive surrounding white matter edema.

15. Choroid plexus carcinoma: Axial T2WI (A), T1WI (B), post-contrast axial (C) and sagittal (D) T1W images revealing a lobulated intensely enhancing right lateral ventricular choroid plexus based mass causing hydrocephalus.

16. Choroid plexus xanthogranuloma Also known as degenerative choroid plexus cyst, they represent collections of cholesterol and lipid-laden histiocytes. They are usually located in the lateral ventricles. On MRI, they are hyperintense on T2-weighted images, do not attenuate completely on FLAIR, and show restricted diffusion on DWI.

17. Choroid glioma Chordoid glioma is a circumscribed, ovoid, homogeneously enhancing mass that is hyperattenuating on CT and slightly hyperintense on T2-weighted MRI.Typical location is anterior wall of 3rd ventricle. Ovoid, slightly lobulated, well circumscribed mass with contact to the anterior wall of the third ventricle. The mass is isointense on T2 weighted sequences and shows vivid uniform enhancement after Gadolinium.

18. CerebelloPontine Angle Tumors

19. Vestibular schwannomas and meningiomas are the two most frequent lesions and account for approximately 85–90% of all CPA tumors. Vestibular Schwannomas Bilateral vestibular schwannomas are pathognomonic for neurofibromatosis type 2(NF2).These are generally benign and slow growing tumors with rare malignant degeneration when associated with NF-1. On imaging, vestibular schwannomas are seen as enhancing CPA mass lesions with variable extension into the internal auditory canal in most cases, resulting in the description of an ‘‘ice-cream cone’’ tumor.It may appear heterogeneous secondary to presence of regions of internal necrosis/cyst formation.

20. Axial T2(A)image shows an iso-hyperintense CPA mass with extension into IAC, areas on susceptibility on SWI (B) and heterogeneous enhancement (C) A patient of neurofibromatosis 2 with bilateral acoustic schwannomas.

21. SELLAR AND PARASELLAR LESIONS Normal sellar anatomy: T1-weighted (A) sagittal and (B) coronal images showing adenohypophysis (short arrow), posterior pituitary bright spot (long arrow), infundibulum, mammillary body (mb),Sphenoid sinus(s), clivus(c) ,optic chiasma(oc),cavernous sinus(cs)and lamina terminalis(lt).Tuber cinereum is the ridge of tissue between mammillary body and infundibulum.

22. Pictorial representation of the coronal view of the sella and parasellar (cavernous sinus) region depicting the anatomy and relationship of various structures.

23. Pituitary adenomas A denomas measuring less than 10 mm are called microadenomas while the larger ones are termed macroadenomas. T1WI are more reliable for detection of adenomas.The addition of Gd enhancement increases the detection rate of microadenomas .Post contrast dynamic acquisition is also very helpful. Signal intensity increases more rapidly and to a greater degree in normal pituitary gland than in microadenoma,however,3–5 minutes following the contrast administration the signal of the normal gland and the adenoma may become identical. The maximum contrast difference between the normal gland and the microadenoma occurs at about 30–60 seconds .Microadenomas also demonstrate slower washout of accumulated contrast that may cause them to appear hyperintense on delayed images.

24. Microadenomas typically appear hypointense compared to the normal adenohypophysis on T1WI and iso to hyperintense onT2WI. Occasionally they may be isointense and can only be detected on enhanced scans(particularly dynamic study) where they stand out as hypointense areas within the enhancing gland.

25. MR has been shown to be useful in precisely demonstrating the cavernous sinus invasion by the macroadenoma. Knosp grading is the mostly used .The grading is defined by the relation of carotid lines with the limits of invasion.These lines pass through supra-and intra cavernous parts of ICA in coronal view. There are medial,median and lateral carotid lines.

26. Craniopharyngioma Epithelial neoplasm arising from rests of Rathke pouch Two types- Adamantinomatous and papillary squamous Suprasellar lesion mostly Can be intrasellar too

27. Axial T1WI (A) and sagittal T2WI (B) show cystic and solid suprasellar mass. Coronal FLAIR (C) shows high signal of the cyst compared to CSF. Enhanced T1WI (D) shows peripheral enhancement of the cyst .Calcification is clearly shown on axial CT.

28. Epidermoid and dermoid tumors

29. EPIDERMOID CYST T1 TI FAT SAT CT DERMOID CYST

30. EMPTY SELLA A thin diaphragm, a sellae and a large hiatus in it are responsible for invagination of CSF space into sella leading to empty sella and compression of the gland. Empty sella may be secondary to surgery and postpartum necrosis too. Imaging typically reveals invagination of suprasellar cistern into the sella compressing the gland against the floor. Pituitary gland is not visualized on this T1 sagittal image.

31. Rathke's Cleft Cysts They form as a result of failure of Rathke's pouch to completely regress. Most of the lesions are small, located within the gland in midline or may be suprasellar. The imaging findings depend on cyst contents. Mucoid contents may appear hyperintense on T1 and T2WI. Serous cysts will have features of typical benign cysts. Lack of solid nodular enhancement is a useful differentiating point from necrosed adenomas and along with lack of calcification from craniopharyngiomas. T1 T2

32. Lymphocytic Hypophysitis This is non infectious inflammatory process of autoimmune etiology affecting woman in late pregnancy or early postpartum period. Imaging will show an intensely enhancing mass with or without extrasellar component.A thick non tapered enhancing stalk can be seen. It is differentiated from Sheehan's syndrome by lack of hemorrhage. Increased bulk of the hypophysis is seen with soft tissue extension into bilateral parasellar regions. Sagittal MR section Demonstrating the same with infundibular thickening and retroclival extension.

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