Brain Tumors Lecture

Introduction

• Brain tumors can be divided into adult and childhood tumors.
• Key to USMLE/medical exams: Use mnemonics to simplify learning and recall.

Adult Tumors

Glioblastoma Multiforme (GBM)

• General: Highly malignant, invasive, often crosses corpus callosum.
• Histology: Pseudo-palisading cells, GFAP (+)
• Mnemonic: Glioblastoma Multiforme (G-P-M)
  • G: GFAP positive
  • P: Pseudo-palisading cells
  • M: Midline crossing & Malignant
• Imaging: Butterfly appearance in the brain.

Oligodendroglioma

• Histology: Chicken-wire capillary pattern, fried egg cells, often calcified
• Mnemonic: Olego-dendro-glioma (Egg-related)
  • Chicken-wire: Chicken lays eggs
  • Fried egg cells
  • Calcification: Eggs provide calcium

Meningioma

• Nature: Benign, superficial location
• Histology: Psammoma bodies, spindle cells, arachnoid origin
• Mnemonic: Men have problems with PSA
  • P: Psammoma bodies
  • S: Spindle cells
  • A: Arachnoid origin

Hemangioblastoma

• Origin: Blood vessel
• Secretion: EPO, causing secondary polycythemia
• Association: von Hippel-Lindau syndrome
• Histology: Thin-walled capillaries
• Mnemonic: Heme-angio-blastoma
  • Heme: Blood, EPO production
  • Angio: Blood vessels
• Association Mnemonic: Von EPOl-lindau
  • Von Hippel-Lindau syndrome: Associated

Pituitary Adenomas

• Types: Lactotrophic, Somatotrophic, Non-functional
• Lactotrophic: Prolactinoma
  • Symptoms: Galactorrhea, amenorrhea in females; gynecomastia, decreased libido in males
• Somatotrophic: Produces GH, TSH, ACTH, FSH, or LH
  • Symptoms: Gigantism/acromegaly, hyperthyroidism, Cushing's syndrome, effects of LH/FSH elevation
• Non-functional: Mass effect
  • Symptoms: Headache, bitemporal hemianopia
• Mnemonic: Add-Anoma
  • Add hormones/mass: Hormones (Prolactin, GH, TSH, etc.) or mass (headache, bitemporal hemianopia)
• Important Point: Google bitemporal hemianopia for visual field defect understanding.

Schwannoma

• Location: Cerebellopontine angle, affects CN VII and CN VIII
• Association: Bilateral schwannomas linked to Neurofibromatosis Type II
• Histology: S-100 positive
• Mnemonic: SCH W (Schwannoma)
  • S: S-100 positive
  • C: Cerebellopontine angle
  • H: Hearing (CN VIII)
  • W: Winking (CN VII)

Childhood Tumors

Pilocytic Astrocytoma

• Histology: Rosenthal fibers, GFAP positive
• Mnemonic: Drew ROSENhaus representing Houston Astros
  • Rosenthal: Agent
  • Astro: Houston Astros

Medulloblastoma

• Histology: Homer-Wright rosettes
• Mnemonic: Blast a homerun
  • Blast: Medulloblastoma
  • Homerun: Homer-Wright rosettes

Ependymoma

• Histology: Perivascular pseudorosettes
• Mnemonic: Append a mama
  • Pseudo-rosette: Gave a rose to mom for forgetting her birthday

Craniopharyngioma

• Key Point: Remnants of Rathke's pouch
• Mnemonic: None needed; just brute memorization.
• Association: If you see Rathke in a question, think of craniopharyngioma

Pinealoma

• Symptom: Parinaud syndrome
• Mnemonic: P for Pinealoma and Parinaud syndrome

Final Notes

• Study mnemonics and buzzwords for exams.
• Follow the Dirty USMLE methodology: Keep it simple and high-yield.

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Remember: These high-yield points and mnemonics are designed to help you ace the neurology section and gain free points on test day!