1F-CNS Flashcards
Most common tumor of the brain
Glial tumors
What grade of Astrocytoma?
Circumscribed; bipolar and multipolar cells, microcysts, Rosenthal fibers, granular bodies, vascular proliferation or focal necrosis
Grade 1: Pilocytic
What grade of Astrocytoma?
- Moderate hypercellularity
- Mild nuclear atypia
- No or minimal mitotic activity
Grade 2: Diffuse
What grade of Astrocytoma?
- Increased cellularity
- Diffuse infiltration
- Increased nuclear atypia
- Increased mitotic activity
Grade 3: Anaplastic
What grade of Astrocytoma?
- Vascular proliferation
- Widespread necrosis
- Crowded anaplastic cells
- Marked nuclear atypia
- Brisk mitotic activity
Grade 4: Glioblastoma
Largest group of gliomas
Grade 2: Diffusely infiltrating astrocytoma
Diffusely infiltrating astrocytoma is most prevalent in what age
Adults
*can also be seen in children; affects all ages
Location of Diffusely infiltrating astrocytoma
At any level of central neuraxis
- Predilection:
- Adults: Supratentorial, cerebral cortex (Cerebral hemisphere)
- Children: Infratentorial, cerebellum
Symptoms of Diffusely infiltrating astrocytoma
- Headaches
- Seizures
- Focal sensorimotor deficits
Three variants of Diffusely infiltrating astrocytoma
- Fibrillary: most frequent; thread-like
- Gemistocytic: plump cells
- Protoplasmic
DIffuse astrocytoma occurring in 3rd-4th decade of life; characterized by discohesive patternless array of glial cells
Fibrillary astrocytoma
Important gross characteristic of Fibrillary astrocytoma
Spatially indistinct
Symptoms presenting in Fibrillary astrocytoma
- Intermittent seizures
- Headache
Microscopic features of Fibrillary astrocytoma
- Calcospherites
- Hair-like cytoplasmic processes
- Microcysts
This evolves from a well-differentiated astrocytoma; Demonstrates nuclear angulation, dense hyperchromasia, pleomorphism, and mitotic figures
Grade 3: Anaplastic astrocytoma
Neoplastic transformation of committed astroglial progenitors
Grade 4: Glioblastoma multiforme
Oncogenic pathways involved in Glioblastoma multiforme
- TP53 mutation/ deletion
- Loss of heterozygosity in chr 10
- EGFR amplification
- PTEN mutation
Glioblastoma multiforme characteristics
- More rapid growth
- Destructive invasion
- Very aggressive
Microscopic features of Glioblastoma multiforme
- Highly cellular
- Mitotically active
- Bizarre multinucleated giant cells or small anaplastic cells
- Coagulative necrosis w/ or w/o palisading cells
- Glomeruloid appearing microvascular proliferation
Well-circumscribed, gelatinous masses often with cysts, hemorrhage, and calcification; occurs in 4th-5th decade of life
Oligodendroglioma
Location of Oligodendroglioma
White matter of cerebral hemisphere
Impt. microscopic characteristic of Oligodendroglioma
Spherical nuclei with halo of cytoplasm (“sunny side up fried egg appearance”)
T or F: Oligodendroglioma has worse prognosis than astrocytoma
FALSE
*Better prognosis than astrocytoma
CNS tumor usually found centrally in the brain or spinal cord; often manifested with hydrocephalus and CSF dissemination
Ependymoma
Locations of ependymoma
● Most often at ependyma-lined ventricular system
● First two decade of life - fourth ventricle
● In adults - spinal cord
Impt. microscopic feature of ependymoma
Ependymal rosette
T or F: Ependymoma has a poor prognosis
TRUE
*because of its behavior and location
Most common mixed gliomas
Oligoastrocytoma
Location of Mixed glioma
- Supratentorial tumors of adulthood
- Favors frontal and temporal lobes
T or F: Mixed gliomas are more common than pure gliomas
FALSE, they are rare
Very aggressive CNS tumors that are common among children; they are derived from primitive neuroepithelial precursors
Embryonal neuroepithelial tumors
Microscopic characteristic of Embryonal neuroepithelial tumors
Small anaplastic cells uncommitted to any particular cytogenetic pathway
Most common primitive neuroepithelial neoplasm in CNS
Medulloblastoma
Very primitive-looking cells coupled with rosette-like configuration
Medulloblastoma
Age of occurrence in Medulloblastoma
Children: 5-10 y/o
Adult: 3rd-4th decade
Location of Medulloblastoma
Cerebellar vermis
- 75% of childhood lesions arise in the cerebellar vermis
- often expanding to fill the 4th ventricle
- producing obstructive hydrocephalus
T or F: Medulloblastoma are highly malignant and are resistant to radiotherapy
FALSE
● Rapid growth (highly malignant)
● Radiosensitive
T or F: When you can identify the tumor from normal tissue, most likely it is benign. Malignant tumors have indistinct borders
FALSE
- When you can identify the tumor from normal tissue, most likely it is MALIGNANT
- BENIGN tumors have indistinct borders
Pineal gland tumor that has an aggressive local growth with destructive invasion of neighboring structures. it has predilection for children and adolescents and has proclivity for dissemination via the CSF
Pineoblastoma
Pineal gland tumor that has a varied histology and unpredictable biologic potential; has rosette structures
Pineocytoma
T or F: What would differentiate medulloblastoma from pineocytoma is the location
TRUE
Most common CNS neoplasm in immunosuppressed patients
Primary brain lymphoma
CNS lesion of B-cell origin, often with multiple tumor masses
Primary brain lymphoma
A common CNS lesion arising from meningothelial cells of the arachnoid which may compress the underlying brain
Meningiomas
T or F: Most meningiomas are benign
TRUE
What grade of Meningioma?
○ Less than four mitotic figures per 10 hpf
Grade I: Meningioma
What grade of Meningioma?
○ Increased mitotic activity: 4-19 per 10 hpf
○ Or three or more of the following:
■ Increased cellularity
■ Small cells with high nuclear-to-cytoplasmic ratio
■ Prominent nucleoli
■ Sheetlike and/or patternless growth pattern
■ Foci of spontaneous or geographic necrosis
Grade II: Atypical meningioma
What grade of Meningioma?
○ Increased mitotic activity >19 per 10 hpf
○ Or malignant and or anaplastic cytologic appearance
Grade III: Anaplastic meningioma
Most frequent nerve sheath tumor; benign
Schwannomas
Location of schwannomas
Adults: Cerebellopontine angle or lumbosacral spinal extramedullary space
Schwannoma that originates in the vestibular branch of the CN VIII
Acoustic schwannoma or neuroma
Microscopic features of Schwannoma
Antoni A, Antoni B, Verrucae bodies
Antoni A vs Antoni B
- Antoni A: very cellular; palisading of the nuclei (verrucae bodies)
- Antoni B: loose area
Malignant counterpart of Scwannoma
Malignant peripheral nerve sheath tumor
Origin of Malignant peripheral nerve sheath tumor
- Half arise de novo
- Other half from nerves involved by neurofibromatosis
Two conditions where MPNST should be the primary consideration
○ When the tumor develops in a patient with a type I Recklinghausen’s disease
○ When the tumor is obviously arising with the anatomic compartment of a major nerve
Histologic characteristics of MPNST
- Serpentine shape of tumor cells
- Arrangements in palisade or whorls
- Marked contrast between deeply
hyperchromatic nuclei and pale cytoplasm - Perivascular concentration of cells
- Abundant mitosis.
Secondary brain tumors origin
- Direct extension
- Hematogenous metastasis
Most common primary sites
Lung, breast, skin, kidney, GIT
T or F: Sarcomas typically spread to the brain directly
FALSE
*Sarcomas typically spread to the lungs first en route to the brain.
Most common location of secondary tumors
Frontoparietal cerebral tissues
Reason behind the common location of secondary tumors
Due to middle cerebral artery
T or F: Metastatic lesions are usually compact in their growth pattern and thus tend themselves to excision
TRUE
Histologic characteristic of Secondary tumors in the brain
Conform to the histology of the primary site.
T or F: A confident diagnosis of metastatic carcinoma can often be made at the time of surgery by examination of the smear or crush preparation showing cellular cohesion of most epithelial neoplasms.
TRUE
