Which statement best describes edema histology?

• A. Expansion of interstitial spaces with pale-staining areas and separation of fibers.
• B. Astrocyte proliferation with scar formation.
• C. Clustering of inflammatory cells.
• D. Replacement by fibrotic tissue.

Answer: (A)

Edema histology is defined by excess fluid in the tissue’s extracellular spaces. In histologic sections, this fluid expansion makes interstitial spaces larger and separates fibers, producing pale, clear-looking areas between tissue elements. This direct expansion of interstitial spaces due to accumulated fluid is the defining feature you’d look for when identifying edema under the microscope.

Other options describe changes that reflect different processes: gliosis with scar formation involves astrocyte proliferation and permanent tissue remodeling; clustering of inflammatory cells points to an inflammatory infiltrate; replacement by fibrous tissue indicates chronic scarring and fibrosis. These are not the immediate, fluid-driven changes seen in edema, which is why the description of expanded interstitial spaces with pale-staining fluid best fits edema histology.