[Changes in the heart in the carcinoid syndrome]

An observation of carcinoid syndrome in a woman of 47 suffering from malignant carcinoid of the ileum with metastases into the liver and right ovary is described. The clinical picture included diarrhea, heat waves, bronchospasms, hypertension, hyperserotoninemia, affection of the mitral valve and left atrium. "Carcinoid plaques" in the endocardium formed due to excessive proliferation under the influence of serotonin and kinins of polypotent subendothelial cells followed by their differentiation into fibroblast-like and smooth-muscle elements and production of basophilic interstitial substance. The receding rheumatic affection of the mitral valve may be the cause of the predominant involvement of the left part of the heart.