Figure 1. (a-c) The large neck lymph nodes involved by Hodgkin lymphoma and the dramatic response to the combination of an immune checkpoint inhibitor with brentuximab vedotin. (d, e) Endomyocardial biopsy findings by light (d) and electron (e) microscopy. (d) The myocardium is free of active inflammatory infiltrates but exhibits evidence of previous myocardial insult represented by a focus of replacement fibrosis (RF, white asterisk) (1-µm section stained with toluidine blue, × 500). (e) Some areas of myocardium had increased interstitial collagen with an occasional macrophage but no aggregates of inflammatory cells between the cardiomyocytes (× 2,000).