Neoplasia: primary CNS lymphoma: practice question

A Pathology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pathology · Neoplasia: primary CNS lymphoma

Sample item

A 34-year-old man with advanced HIV infection (CD4 count 40 per microlitre) has headache and confusion. MRI shows a single periventricular ring-enhancing lesion, CSF PCR is positive for EBV DNA, and Toxoplasma serology is negative. What is the most likely histology?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Diffuse large B-cell lymphoma

In AIDS, a solitary periventricular enhancing mass with EBV in the CSF and negative Toxoplasma serology suggests primary CNS lymphoma, which is almost always a diffuse large B-cell lymphoma driven by EBV. Toxoplasmosis usually gives multiple ring-enhancing lesions with positive serology, whereas PML does not enhance.

Option by option

  • A. Diffuse large B-cell lymphoma (correct)

    Correct. EBV-driven diffuse large B-cell lymphoma is the typical primary CNS lymphoma of advanced HIV.

  • B. Toxoplasma abscess

    Toxoplasma abscesses are usually multiple and Toxoplasma serology would be positive.

  • C. Glioblastoma

    Glioblastoma has a butterfly distribution and is not associated with CSF EBV DNA in AIDS.

  • D. Progressive multifocal leukoencephalopathy

    Progressive multifocal leukoencephalopathy shows white matter demyelination without mass effect or enhancement.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is A, Diffuse large B-cell lymphoma. In AIDS, a solitary periventricular enhancing mass with EBV in the CSF and negative Toxoplasma serology suggests primary CNS lymphoma, which is almost always a diffuse large B-cell lymphoma driven by EBV.

Why is "Toxoplasma abscess" not the answer?

Toxoplasma abscesses are usually multiple and Toxoplasma serology would be positive.

Why is "Glioblastoma" not the answer?

Glioblastoma has a butterfly distribution and is not associated with CSF EBV DNA in AIDS.

Why is "Progressive multifocal leukoencephalopathy" not the answer?

Progressive multifocal leukoencephalopathy shows white matter demyelination without mass effect or enhancement.

What concept does this question test?

It tests Neoplasia: primary CNS lymphoma in Pathology. Toxoplasmosis usually gives multiple ring-enhancing lesions with positive serology, whereas PML does not enhance.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neoplasia: primary CNS lymphoma?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.