CNS Neoplasms - Ojemann/DeMasters Flashcards
Pilocytic Astrocytoma (Epidemiology/age, location, WHO grade, genetics, histology, staining)
Age - Common in children (the most common CNS neoplasm of childhood)
Location - Cerebellum, optic pathway, hypothalamus [thalamus, spinal cord, temporal lobe]
WHO classification - WHO Grade I, easy surgical resection for CURE
Genetic mutation - BRAF/KIAA mutation leads to Oncogene Induced Senescence
Histology/Other - Rosenthal fibers, immunostain GFAP.
Other - Assx with NF1 (neurofibrin involved in the RAS/RAF pathway)
Ganglioglioma (WHO Grade, histologic features/location)
Not mentioned in lecture.
WHO grade I
Calcified, well circumscribed, often in the temporal lobe.
Choroid Plexus Papilloma (WHO Grade)
WHO Grade I
NOT an ependymoma. Causes obstructive hydrocephalus by blocking the foramina
Diffuse Astrocytoma
Age - 30/40
Location - Cerebral hemispheres (occurs where pilocytic astrocytoma doesn’t)
WHO Grade II - not amenable to surgical resection
Oligodendroglioma (Age, location, WHO grade, Genetics, Histology)
Age: 42 (mean)
Location: Cerebral white matter (frontal/parietal/temporal/occipital, 3:2:2:1 by mass)
WHO Grade II
Genetics: 60-80% have LOH 1p, 19q, positive survival factor
Histology - Bright white calcifications on imaging, “fried egg” appearance on histology.
MNEMONIC: Oligodendrogliom”egg”: Ca in the fried-eggshell.
Ependymoma (Age range, location (pediatric/adult), WHO grade)
Age: Pediatric (0-20)
Location: intraventricular (4th ventricle), often present with obstructive hydrocephalus. Spinal cord = adult
WHO Grade II or III
Anaplastic Astrocytoma (Age, location, WHO grade, genetics, histology)
Age - 45 years (mean)
Location - Cerebral Hemispheres
WHO Grade III - Nonresectable
Genetics - TP53 mutation (grandparent is IDH, along with oligodendroglia)
Histology - more mitoses but no vascularization/necrosis (mitotic increase, not size gives the WHO III score) more atypical nuclei
Anaplastic Oligodendroglioma (Age, location, WHO grade, Genetics, histology)
Age: 42 years (mean)
Location: Cerebrum (3/2/2/1)
Who Grade III: grading is more lenient for the oligodendrogliomas than for the astrocytomas, so some vascularization and necrosis is allowed, while still remaning a WHOIII. An asytrocytoma with these characteristics would be a GBM)
Genetics: 60-80% have 1p, 19q, positive predictor of survival (detect with FISH, look for deletion - red dot missing)
Histology: MIB1 immunostain highlights cells not in G0, allows distinction of cells not visible on LM.
Glioblastoma (GBM) (Age, location, WHO grade, genetics, histopathology, other)
Age: Primary (62) Secondary (45)
Location: Cerebral hemispheres
WHO Grade IV
Genetics: “Paracrine growth loop”–> Hif1–>VEGF–>vascularization
Histopathology: highly necrotic/mitotic/dedifferentiated. Cause “leaks” in the BBB, leading to bright signals on MRI
Other: sometimes arise in multiple sites at once (can pretend as metastatic). less than 3% 5 year survival.
**The term glioblastoma is synonymous with astrocytoma, WHO grade IV.
Medulloblastoma (Age, epidem, location, mortality, WHO grade, other)
Age: Pediatric (3-8 y/o). THE most common malignant tumor in children.
Location: Cerebellum, by definition
ALL MEDULLOBLASTOMA ARE GRADE IV!!!!!!!!!!!!!!!
50% survival
Other: MEDULOBLASTOMA are an exception to the rule that brain tumors don’t metastisize. They tend to spread through the CSF pathways. This is opposed to all other tuors of the brain which almost never spread.
Meningiomas (Age, location, WHO grade, other)
Age: women in their 50s (due to presence of estrogen receptor - Pathoma). Almost never in children.
Location: Dura/calvarium
WHO Grade I (stated twice in lecture)
Other: “push and shove, don’t invade” Typical appearance – superficial, often attx to dura. Bulbous mass with pseudopod extensions (dural tail). Makes for an easy neuroimaging diagnosis. Can also extend through bone. Can occur in a variety of locations. These tumors are not fatal today…but only as a result of very complex and difficulty surgeries if in difficult locations.
Schwannomas (Speed, location, other names)
Slow growing, rare transformation to malignancy
Tumors of nerve and nerve covering. Olfactory bulb and optic nerve use CNS (oligo). The rest of the cranial nerves use schwann cells. Cranial nerve 8 is the most common, hence acoustic neuroma. Commonly presents with tinnitus.
[Bilateral acoustic neuroma assx with NF2 - Pathoma]
Most brain tumors are primary/metastatic?
Metastatic (150,000) vs (35,000 primary)
What three types of tumors are “gliomas”? From what tissue (precursor) do they arise?
Astrocytomas
Ependymomas
Oligodendrogliomas
Arise from the neuroectoderm.
What are the 5 most common sites for metastases to brain?
Breast Lung Kidney GI Melanoma
What differentiates primary from secondary GBM?
Primary arises de-novo. Secondary progresses from a lower grade glioma.
Primary is EXTREMELY RAPID TIME COURSE (eg doubling in size in 4 months instead of 4 years for secondary)
Primary GBM likely has (EGFR/EGFRvIII) mutation) [50%]
What’s the deal with the IDH mutation? How common is it, and in what types of neoplasms does it occur?
Where do you NOT see the IDH mutation?
How can one test for the IDH 1/2 mutation?
IDH occurs in 60-80% of WHO grade II and III astrocytomas and oligodendrogliomas.
NOT SEEN in pilocytic astrocytomas OR in Primary GBM (extremely rare).
IDH1 antibody is 100% specific in WHO II/III. Will miss a small percent, including all IDH2.
In a patient with a headache, what must you check? Why? What are you looking for, and what will these findings/lack thereof tell you?
Retina. Looking for papilledema.
Axons of the retina are swollen b/c axoplasmic flow inhibited. Capillaries are also blocked so the retinal veins are blocked causing hemorrhage. Don’t miss this in a patient w/headache because it signifies increased ICP
WHO Grade I tumors (4 specific examples)
Pilocytic Astrocytoma
Choroid Plexus Papilloma
Meningiomas
Ganglioglioma (not mentioned in lecture, but in notes)
WHO Grade II (3 examples)
Diffuse Astrocytoma
Oligodendroglioma
Ependymoma
WHO Grade III (3 examples)
Anaplastic Astrocytoma
Anaplastic Oligodendroglioma
Anaplastic Ependymoma
WHO Grade IV (2 examples)
Glioblastoma
Medulloblastoma
Which tumor type tends to spread down the CSF axis?
Medulloblastoma
What does a 1p/19q co-deletion signify?
Unbalanced translocation t(1;19)(q10;p10). A 1q19p chromosome is preserved. (FISH)
“Established marker” of oligodendroglial tumors (60-80% have this mutation).
(Can differentiate between anaplastic oligodendroglioma and anaplastic astrocytoma)
