Which histologic finding indicates tissue edema?

• A. Eosinophilic necrosis.
• B. Hypercellularity.
• C. Expansion of interstitial spaces with pale-staining areas and separation of fibers.
• D. Increased collagen deposition.

Answer: (C)

Edema shows fluid accumulating in the tissue’s extracellular spaces, widening the gaps between cells and fibers. Histologically this appears as expanded interstitial spaces with pale-staining (clear) areas that separate and push apart the fibers, reflecting the presence of interstitial fluid. That’s why this finding is the best indicator of edema.

Eosinophilic necrosis indicates cell injury with bright eosin staining of damaged cells, not fluid accumulation. Hypercellularity means more cells are present, such as inflammatory cells or proliferating cells, rather than expanded fluid-filled spaces. Increased collagen deposition points to fibrosis or scarring, not edema.