A lesion resulting from infarction or hemorrhage appearing as an anechoic area within brain tissue is called which condition?

• A. Porencephaly
• B. Prosencephaly
• C. Encephalocele
• D. Hydrocephalus

Answer: (A)

A fluid-filled cavity within brain tissue caused by prior injury is called porencephaly. It shows up as an anechoic (fluid) area in the cerebral parenchyma that often communicates with the ventricular system or subarachnoid spaces, and its walls are typically thin and gliotic. This distinguishes it from other conditions: prosencephaly is a forebrain developmental malformation; encephalocele is brain tissue herniating through a skull defect; and hydrocephalus is dilation of the ventricular system rather than a discrete parenchymal cavity. Porencephaly can be unilateral or bilateral and reflects an insult such as infarction or hemorrhage during brain development.