**Question:** Intracranial calcification with cystic lesion in plain X-Ray skull is seen in

A. Hydrocephalus
B. Encephalitis
C. Meningioma
D. Alzheimer's disease

**Correct Answer:** .

**Core Concept:** Intracranial calcification and cystic lesions are radiological findings that can be indicative of specific neurological disorders. Intracranial calcification refers to the presence of calcium deposits within the brain, while a cystic lesion denotes the presence of a cavity filled with fluid or other substances. Both of these findings can be observed on plain X-Ray skull.

**Why the Correct Answer is Right:** The correct answer, **D. Alzheimer's disease**, is chosen because it is a neurodegenerative disorder characterized by the presence of extracellular amyloid-beta plaques and intracellular neurofibrillary tangles in the brain. Intracranial calcification, particularly in the temporal lobes, is a common radiological finding in Alzheimer's disease. The cystic lesion in this context represents the presence of neurofibrillary tangles.

**Why Each Wrong Option is Incorrect:**

A. **Hydrocephalus** is a condition characterized by an abnormal accumulation of cerebrospinal fluid in the brain ventricles and subarachnoid space, leading to increased intracranial pressure. Intracranial calcification is typically not a feature of hydrocephalus, which is caused by obstruction of cerebrospinal fluid flow or overproduction.

B. **Encephalitis** is an inflammation of the brain, often caused by an infection, autoimmune response, or tumor infiltration. Intracranial calcification is generally not a prominent feature of encephalitis, as the primary focus of the disease is inflammation rather than calcification.

C. **Meningioma** is a benign tumor that develops from meninges, the protective membranes covering the brain and spinal cord. Intracranial calcification may be present in meningiomas, but it is not specific to this condition. Other causes of calcification, such as aging or calcification due to trauma, may also produce similar findings.

**Clinical Pearl:** Although not the primary cause, calcification and cystic lesions can be observed in various neurological conditions, making them nonspecific findings. A comprehensive clinical assessment and correlation with other imaging modalities like MRI or CT scan, along with clinical context, are essential for accurate diagnosis and management planning.