Which of the following is the most common CNS tumor associated with HIV infection?
**Core Concept**
The question is testing the association between HIV infection and central nervous system (CNS) tumors. HIV infection is known to impair the immune system, making individuals more susceptible to opportunistic infections and malignancies, including CNS tumors.
**Why the Correct Answer is Right**
Primary CNS lymphoma (PCNSL) is a type of non-Hodgkin lymphoma that arises in the brain or spinal cord. It is strongly associated with HIV infection, particularly in individuals with advanced immunosuppression (CD4 count < 100 cells/μL). PCNSL is thought to arise from the proliferation of activated B cells in the CNS, which are often infected with Epstein-Barr virus (EBV). The pathogenesis of PCNSL involves the dysregulation of the immune system, allowing EBV-infected B cells to accumulate and proliferate in the CNS.
**Why Each Wrong Option is Incorrect**
**Option A:** Glioblastoma is a primary brain tumor, but it is not specifically associated with HIV infection. It is a type of astrocytoma that arises from the astrocytes in the brain.
**Option B:** Meningioma is a type of tumor that arises from the meninges, the protective membranes surrounding the brain and spinal cord. While it is a common CNS tumor, it is not specifically associated with HIV infection.
**Option C:** Ependymoma is a type of tumor that arises from the ependymal cells lining the ventricles and central canal of the spinal cord. It is not specifically associated with HIV infection.
**Clinical Pearl / High-Yield Fact**
In patients with HIV infection, PCNSL often presents with nonspecific symptoms such as headache, confusion, and seizures. It is essential to consider PCNSL in the differential diagnosis of CNS symptoms in HIV-infected individuals, particularly those with advanced immunosuppression.
**Correct Answer:** C. Primary CNS lymphoma (PCNSL) is the most common CNS tumor associated with HIV infection.