CNS TUMORS

Metastatic tumors are more common than Primary tumors

Malignant CNS tumors rarely metastasize outside cranial cavity

Benign tumors can have devastating effects

Difference between Primary &Secondary Brain Tumors Poorly Circumscribed Single

Well circumscribed Multiple

Clinical features

Raised intracranial pressure Headache, nausea, vomiting Focal neurological signs weakness Seizures

Papilledema

Decreased strength in arm and leg

Brisk deep tendon reflexes

A ring-enhancing mass on CT scan

Gliomas

1. Astrocytomas

2. Oligodendroglioma

3. Ependymoma PNETs Medulloblastoma Non parenchymal tumors Meningioma

Classification

FREQUENY OF CNS TUMORS

Adults Astrocytoma( Glioblas

toma multiforme) Meningioma Schwanoma Ependymoma

Children Cerebellar

Astrocytoma Medulloblastoma

Ependymoma

Astrocytomas

1. Fibrillary astrocytic neoplasms Astrocytoma

Anaplastic astrocytoma Glioblastoma multiform

1. Pilocytic astrocytoma

Most Frequent Infiltrative growth Grade I - IV

Increased cellularity Nuclear Pleomorphism Mitotic activity Endothelial proliferation Necrosis - palisading

Fibrillary Astrocytic Neoplasms

Astrocytoma ,low and high grade.

Low grade. High grade.

A glioblastoma multiforme (GBM).

These neoplasms are quite vascular with prominent areas of necrosis and hemorrhage

pseudopalisading necrosis of neoplastic cells in a glioblastoma multiforme (GBM).

Tumors of the first two decades

Outer granular cell layer

Cerebellum

Disseminate through CSF

Small blue cell tumors with minimal differentiation if any

PNET (Medulloblastoma)

The irregular posterior fossa mass that is seen here near the midline of the cerebellum and extending into the fourth ventricle above the brainstem is a medulloblastoma. This is one of the "small round blue cell" tumors and it most often occurs in children.

microscopic appearance of medulloblastoma with small round blue cells.

Tumors of the adults Meningiothelial cells of arachnoid More in females Convexities of brain, olfactory groove,

lesser wing of sphenoid and spinal cord (thoracic segment)

Meningioma

Meningioma beneath the dura

Firm , indent (not invade) Note how this meningioma

beneath the dura has compressed the underlying cerebral hemisphere.

Swirling masses of meningoepithelial cells, spindle shaped cells with indistinct borders arranged in whorls or fascicles.

Whorls of polyhedral cells.

Schwannoma

Benign tumor of schwann cells Cerebellopontine angle and VIII nerve

(Acoustic neuroma) Tinnitus and sensorineural deafness Cells are immuno reactive for protein

S-100 Good prognosis

Schwannoma

It is a neurilemmoma which arises from the nerve sheath Schwann cells

Benign Associated with

Neurofibromatosis NF 2 gene mutation on chromosome 22

Well circumscribed, encapsulated, firm gray masses attached to nerve but can be separated

"Antoni A“ with hypercellular and scant stroma

Antoni B" pattern with a looser stroma, fewer cells.

Ependymoma

Benign 4th ventricle in children & lumbocasral spinal cord

in adults Obstructive hydrocephalus Perivascular pseudorosettes _ependymal cells

around vascular channels Recur after surgery and acquire more

aggressive behavior

The microscopic appearance of an ependymoma reveals a rosette pattern with the cells arranged about a central vascular space.

Oligodendroglioma

Type of glioma that are believed to originate from the oligodendrocytes

Perinuclear halo _ fried egg appaearance Slow growing recur after surgery and

degenerate into high grade gliomas overtime

High magnification micrograph of an oligodendroglioma showing the characteristic fried egg-like cells, with clear cytoplasm and well-defined cell borders.