How can myocyte organization help distinguish hypertrophic cardiomyopathy from hypertensive heart disease on biopsy?

How can myocyte organization help distinguish hypertrophic cardiomyopathy from hypertensive heart disease on biopsy?

• A. Hypertrophic cardiomyopathy shows myocyte disarray with interstitial and replacement fibrosis.
• B. Hypertrophic cardiomyopathy shows myocyte hypertrophy with concentric fibrosis only.
• C. Hypertrophic cardiomyopathy shows arteriolosclerosis of small arteries.
• D. Hypertrophic cardiomyopathy shows myocyte disarray with interstitial and replacement fibrosis; hypertensive heart disease shows myocyte hypertrophy with concentric fibrosis but not disarray.

Answer: (D)

The main idea is that biopsy reveals distinct patterns of myocyte organization in these conditions. Hypertrophic cardiomyopathy typically shows myocyte disarray, where muscle fibers are haphazardly arranged, along with interstitial and sometimes replacement fibrosis. Hypertensive heart disease, by contrast, results from chronic pressure overload and shows uniform myocyte hypertrophy with concentric remodeling and fibrosis, but without disarray. Therefore, a description that pairs disarray with interstitial and replacement fibrosis for HCM and contrasts it with orderly myocytes and concentric fibrosis for hypertensive heart disease best distinguishes the two. The other options either miss the disarray feature or attribute non-diagnostic findings (like arteriolosclerosis) to HCM.

The main idea is that biopsy reveals distinct patterns of myocyte organization in these conditions. Hypertrophic cardiomyopathy typically shows myocyte disarray, where muscle fibers are haphazardly arranged, along with interstitial and sometimes replacement fibrosis. Hypertensive heart disease, by contrast, results from chronic pressure overload and shows uniform myocyte hypertrophy with concentric remodeling and fibrosis, but without disarray. Therefore, a description that pairs disarray with interstitial and replacement fibrosis for HCM and contrasts it with orderly myocytes and concentric fibrosis for hypertensive heart disease best distinguishes the two. The other options either miss the disarray feature or attribute non-diagnostic findings (like arteriolosclerosis) to HCM.