WBR0613
| Author | [[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Serge Korjian M.D. and Yazan Daaboul, M.D.)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A 10-year-old child is brought to the neurology clinic for worsening chronic headache and gait disturbance. CT scan demonstrates a well-circumscribed mass in the cerebellum with both solid and cystic components. The tumor is successfully resected and treatment is initiated based on the histopathological findings (shown below). What is the most likely function of the cells from which this tumor arises?
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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::Given the age of the patient, the subtentorial location of the mass, and the cystic and solid features, pilocytic astrocytoma is the most likely diagnosis. Pathology of the tumor reveals Rosenthal fibers which are eosinophilic corkscrew fibers classically observed in pilocytic astrocytoma tumors. The diagnosis can usually 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:: |
