LAUSR

Abstract Rationale: Venous leiomyosarcoma (LMS) is a malignant tumor arising from the smooth muscle cell of the vein wall. The diagnosis of venous LMS is usually delayed owing to its rarity, absence of serological markers, and mimicry with deep vein thrombosis (DVT). Herein, we report a case of a primary external ilian vein LMS characterized by long-term, unexplained DVT in the left lower limb. Contrast-enhanced ultrasound (CEUS) played a crucial role in the preoperative diagnosis. No improvement was observed in the lower limb status; a rapid, high-level, heterogeneous wash-in and wash-out mass of the vein, as seen with CEUS, could indicate angiogenic malignancy. CEUS also helped evaluate the percent of intratumoral necrosis, which is an important parameter for predicting the prognosis. Patient Concerns: A 37-year-old Chinese women presented to the Vascular Surgery Department of our hospital for accurate diagnosis of her condition. She began experiencing edema and pain in her left leg 2 years ago. She was diagnosed with DVT in the left lower extremity and was administered anticoagulant therapy since then. However, her symptoms started to aggravate 8 months ago. Diagnoses: The laboratory results including D-dimer, prothrombin time (PT), activated partial thrombin time (APTT), and prothrombotic conditions screening were within normal ranges. A pelvic ultrasound detected a heterogeneous, hypoechoic mass compressing the external iliac vein and obstructing the venous drain of the lower extremity. The mass showed a rapid, high-level, heterogeneous wash-in and wash-out on CEUS, which suggested angiogenic malignancy. Contrast-enhanced CT (CECT) confirmed the result of CEUS but revealed no metastasis. Interventions: She underwent complete surgical removal of the tumor, which was resected successfully. There was no infiltration in the inguinal nodes sent for the study. Outcomes: Pathological examination and immunohistochemistry confirmed that the mass was a well-differentiated LMS originating from the external iliac vein. There was no sign of local recurrence or distant metastasis during a 12–month follow-up. Lessons: Effective imaging techniques and differential diagnosis of venous LMS is vital and should be considered for patients with chronic thrombosis presenting with normal laboratory results.