{Reference Type}: Case Reports {Title}: Cardiac-to-Bronchial Fistula in Hepatocellular Carcinoma: A Case Report. {Author}: Chen HH;Lai YH;Wu CC;Hsieh WP; {Journal}: Medicina (Kaunas) {Volume}: 60 {Issue}: 6 {Year}: 2024 Jun 14 {Factor}: 2.948 {DOI}: 10.3390/medicina60060982 {Abstract}: Hepatocellular carcinoma (HCC) stands as a significant contributor to cancer-related mortality globally. While the acute and often fatal manifestations of locally advanced HCC primarily present within the abdomen, it is crucial to recognize that the respiratory and circulatory systems can also fall victim due to the liver's unique anatomical position within the body. Here, we present the case of a 63-year-old male recently diagnosed with locally advanced HCC with vascular invasion. Shortly after receiving target therapy and focal radiotherapy, the patient developed repeated secondary infections and a persistent diaphragmatic defect. As the necrotic tissue invaded the pleural space, subsequent tumor-to-bronchial and tumor-to-cardiac fistulas emerged, resulting in an abnormal connection between the respiratory and cardiovascular systems, leading to massive air emboli in circulation. This report highlights the risk of supradiaphragmatic complications in HCC patients with post-treatment secondary infections, particularly in patients predisposed to developing diaphragmatic defects.