WBR0613
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A 10-year-old child was brought by his mother to the neurology clinic for worsening chronic headache and gait disturbance. A well-circumscribed mass with solid and cystic component is detected in the cerebellar region on CT-scan. Shown below is a pathology image of the tumor following resection. The tumor is most likely derived from cells that have which of the following functions?
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| Answer A | AnswerA::Reactive gliosis |
| Answer A Explanation | [[AnswerAExp::Astrocytes play a role in reactive gliosis.]] |
| Answer B | AnswerB::Phagocytosis |
| Answer B Explanation | [[AnswerBExp::Microglia play a role in phagocytosis.]] |
| Answer C | AnswerC::Myelin production |
| Answer C Explanation | [[AnswerCExp::Schwann cells and oligodendrocytes produce myelin.]] |
| Answer D | AnswerD::Action potential generation |
| Answer D Explanation | [[AnswerDExp::Neurons are responsible for the generation and propagation of action potentials.]] |
| Answer E | AnswerE::Production of CSF |
| Answer E Explanation | [[AnswerEExp::Ependymal cells in the inner lining of the ventricles produce CSF.]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::The age of the patient, the location of the mass in the cerebellar lesion and the cystic and solid characteristic of tumor increase the suspicion of a pilocytic astrocytoma. The pathology image of the tumor reveals Rosenthal fibers which are eosinophilic corkscrew fibers that are found in pilocytic astrocytoma. The diagnosis can be confirmed with GFAP staining. Astrocytes play a role in the maintenance of the blood brain barrier, regulation of potassium metabolism and reactive gliosis.
Shown below is an image depicting Rosenthal fibers.
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| Approved | Approved::No |
| Keyword | WBRKeyword::Pilocytic astrocytoma, WBRKeyword::brain tumor, WBRKeyword::astrocytes, WBRKeyword::reactive glioma |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
