Cardiac intracavitary metastasis is very uncommon. In a 55-year-old man presenting with a massive pulmonary embolism pattern, transthoracic echocardiography (TTE) allowed us to visualize an isolated right ventricular metastasis extended into the pulmonary trunk. It led to the discovery of a primary testis embryonal carcinoma. No intracaval and right atrial localization was observed. Despite an urgent complete cardiac metastasis resection and concomitant orchidectomy, TTE showed on postoperative day 6 an uncommon total intracardiac regrowth spreading again to the pulmonary trunk. Combination chemotherapy (etoposide, cisplatin, and bleomycin) was immediately undertaken. This is the first well-documented case of an isolated right ventricular germ-cell cancer metastasis extended into the pulmonary trunk, without intracaval and right atrial involvement, where the outcome was marked with immediate regrowth despite cardiac surgery and orchidectomy. In conclusion, TTE should be considered alongside germ-cell cancer standard staging procedures.