Stage IV EGFR-mutated lung adenocarcinoma with suspected myocardial metastasis responding to afatinib plus chemotherapy

What happened, in summary

This man in his 50s was diagnosed with adenocarcinoma of the right lower lung after percutaneous lung biopsy. He had smoked about 0.5 pack per day for 40 years. Chest CT showed a 4 x 3 cm solid lung mass with pleural traction and enlarged mediastinal lymph nodes. PET-CT showed metastatic uptake in mediastinal lymph node stations 3A, 4R, 9R, and 10R, and also showed intense FDG uptake in the left ventricular myocardial region. Because heart biopsy was considered high risk, cardiac MRI was used to clarify the finding. MRI showed strip-like abnormal areas in the basal inferolateral and anterolateral left ventricle, measuring about 23 x 13 x 29 mm, and the team treated this as suspected myocardial metastasis from lung cancer. Genetic testing showed EGFR exon 21 L861Q mutation, TP53 mutation, MET missense mutation, PIK3CA missense mutation, and PD-L1 TPS/CPS of 65%. His team chose first-line afatinib combined with AP chemotherapy, meaning pemetrexed plus cisplatin. After 2 courses over 6 weeks, cardiac MRI showed the myocardial lesion had decreased to 17 x 12 x 26 mm. Myocardial markers, NT-proBNP, and repeat ECG monitoring stayed stable, and he had no cardiovascular events. As of December 2025, he was responding to systemic therapy, with local treatment reserved for future cardiac activity or symptoms. The case is clinically notable because the heart involvement was found before chest pain, arrhythmia, tamponade, or heart failure occurred. Echocardiography was still unrevealing, so PET-CT and cardiac MRI drove the cardiac assessment and ongoing surveillance plan.