Hypertrophic Cardiomyopathy - HCM III

Myocyte disarray is a prominent feature of hypertrophic cardiomyopathy. The left upper image shows a medium power magnification shows several myocytes forming a disorganized, criss-crossing bundles rather than uniform parallel bundles of mycoytes.  In addition an increased number of interstitial cells is noted. (Masson trichrome stain).  The inset area is shown enlarged in the right upper image whish shows that individual myofibrils within the myocytes show disarray. (Masson trichrome stain).   In turn, the black and white image is an electron micrograph showing actual disarray of the sarcomeres that form the myofibrils. (Uranyl actetate and lead citrate stain)
The left lower panel shows a dysplastic small intramural corornary artery present in this interventricular septal myectomy specimen. (H&E).   The image on the right lower panel is the same artery stained with a Masson trichrome stain.   Small intramural coronary artery dysplasia is a common finding in hypertrophic cardiomyopathy.