Cardiac Sarcoidosis : Microscopic
The predominant histologic finding in cardiac sarcoidosis is scar-like lesions with non-caseating epithelioid granulomas and multinucleated giant cells throughout the full thickness of the myocardium. The sarcoid granulomas are distributed along the lymphatics which are especially numerous around cardiac conduction system tracts. The granulomas (shown here) are well-demarcated and associated with a mononuclear inflammatory infiltrate consisting of histiocytes and small lymphocytes. Rarely, eosinophils may be present. The surrounding myocytes are largely unaffected and without significant necrosis. Diffuse or focal interstitial fibrosis is usually present.