Trousseau's Syndrome With Non-bacterial Thrombotic Endocarditis Associated With Endometrioid Carcinoma in a Young Patient.

Trousseau's syndrome is a malignancy-associated hypercoagulable state characterized by recurrent or migratory thromboembolic events. Although frequently linked to adenocarcinomas, its association with endometrioid ovarian carcinoma in young patients is infrequently documented in the literature, posing significant diagnostic and therapeutic challenges. We report the case of a 29-year-old woman with no prior medical history who presented with acute deep venous thrombosis, bilateral pulmonary embolism, and subsequent arterial thrombotic events, including multiple ischemic strokes. Further work-up demonstrated a left adnexal lesion classified as O-RADS (Ovarian-Adnexal Reporting and Data System) 5 in the absence of thrombophilia or antiphospholipid antibodies. Transthoracic echocardiography identified a mitral valve sessile mass consistent with non-bacterial thrombotic endocarditis (NBTE). Exploratory laparotomy confirmed an endometrioid ovarian carcinoma (FIGO (International Federation of Gynecology and Obstetrics) stage IC2) arising from endometriosis. This case highlights the complexity of hypercoagulability associated with occult malignancy and underscores the importance of considering an underlying neoplasm in young patients with unexplained venous or arterial thrombosis. Trousseau's syndrome should be included in the differential diagnosis of recurrent or idiopathic thrombotic events in young individuals. In cases of unexplained or recurrent thrombosis, clinicians should consider a tailored oncologic work-up to investigate potential underlying malignancies and improve clinical outcomes.