Deep Venous Thrombosis as the Sentinel Event Unmasking a Uterine Leiomyosarcoma in a Postmenopausal Woman: A Case Report and Review of the Literature.

Introduction: Uterine tumors are classified as benign or malignant, with leiomyomas being the most common benign type and leiomyosarcomas (LMSs) being a rare but aggressive form of uterine sarcoma. The clinical similarity between these two tumor types often makes preoperative differentiation challenging, necessitating surgery for a definitive diagnosis. LMSs are highly aggressive with a poor prognosis. We present the case of a 60-year-old woman whose uterine LMS was initially diagnosed as a benign myoma, with deep venous thrombosis (DVT) serving as an atypical presenting sign of her underlying malignancy. Case Presentation: A 60-year-old postmenopausal woman presented with a large, progressively enlarging abdominal mass, which had been identified 5 years prior as a probable leiomyoma. She initially declined surgery but was readmitted 1 month later with a DVT in her left leg, which was attributed to the compressive effect of the large pelvic mass. The patient underwent a total abdominal hysterectomy. Histopathological and immunohistochemical analysis of the 21-cm uterine tumor confirmed a high-grade LMS. Subsequent staging scans revealed Stage IVB metastatic disease in her lungs, liver, and bones. The patient was transitioned to palliative care and passed away 6 weeks after her surgery. Conclusion: Uterine LMSs can deceptively mimic benign leiomyomas, which may lead to significant diagnostic delays and contribute to poor outcomes. This case highlights that an atypical presentation, such as an idiopathic deep vein thrombosis, should heighten clinical suspicion for an underlying pelvic malignancy, even in the absence of typical gynecological symptoms. Accurate and timely diagnosis is critical and ultimately depends on definitive histopathological evaluation, underscoring the highly aggressive nature and significant mortality associated with this rare cancer.