RESUMEN
A 47-year-old woman was admitted to the hospital because of dyspnea for the past three months. She was previously diagnosed with pulmonary embolism. She had been operated on for a colon tumor five years ago and no residual cancer was detected on oncological follow-up. Her transthoracic echocardiographic and transesophageal echocardiographic evaluation showed a hypertrophic right ventricle occupied by a 2.7 x 4.8 cm immobile mass obliterated to the right ventricle cavity. All the non-invasive tests were consistent with thrombus prediagnosis. She underwent surgery. Mass was resected from the right ventricle as much as possible. Histopathology of surgical material revealed metastatic spindle cell adenocarcinoma. We aim to increase the awareness of the differential diagnosis of thrombus or tumor, thereby leading to appropriate management.