In patients of acquired immunodeficiency syndrome, the commonest cause of space occupying lesion in brain is –
**Core Concept**
The question tests the understanding of the most common cause of space-occupying lesions in the brain in patients with Acquired Immunodeficiency Syndrome (**AIDS**). This requires knowledge of the neurological complications associated with **HIV** infection.
**Why the Correct Answer is Right**
In **AIDS** patients, the compromised immune system makes them susceptible to opportunistic infections and malignancies. The most common cause of space-occupying lesions in the brain is **Toxoplasmosis**, which is an opportunistic infection caused by the parasite *Toxoplasma gondii*. This condition leads to the formation of cerebral abscesses.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because while primary central nervous system lymphoma is a concern in **AIDS** patients, it is not the most common cause.
**Option B:** Incorrect as progressive multifocal leukoencephalopathy is another opportunistic infection affecting the brain but is less common than toxoplasmosis.
**Option D:** Incorrect because although other opportunistic infections can cause brain lesions, toxoplasmosis is the most prevalent.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that in **AIDS** patients with neurological symptoms, **Toxoplasmosis** should be considered as a primary diagnosis due to its high prevalence.
**Correct Answer:** D. Toxoplasmosis.