Recurrence Leiomyosarcoma of the Popliteal Vein: A Rare Soft Tissue Sarcoma.

Background: Leiomyosarcoma (LMS) is a soft tissue sarcoma that originates from smooth muscle cells and constitutes approximately 5-10% of all soft tissue sarcomas. Vascular LMS is the least common subtype of LMS. About one-third of vascular LMS is located in the extremities, most commonly in the saphenous vein (25%). Vascular LMS originating from the popliteal vein is very rare, and to the best of our knowledge, only nine cases have been reported to date. Case presentation. We herein report a case of a 49-year-old woman who presented with recurrence of a mass that was located at the posterior aspect of the right proximal leg and extended to the popliteal fossa. She had mild pain and intermittent claudication without a history of an edematous leg. The tissue diagnosis was LMS. Wide en bloc resection of the tumor, including the segment of the involved popliteal vein, was performed without venous reconstruction. The patient received no other adjuvant treatments. At the 16-month follow-up, she had good oncologic and functional outcomes.

Conclusion: Vascular LMS at the popliteal vein is uncommon but should be considered as a differential diagnosis in a patient who presents with a mass at the popliteal fossa. The magnetic resonance imaging (MRI) and core needle biopsy were needed for a definite diagnosis. The mainstay of treatment is wide en bloc resection of the tumor, including the involved segment of the vein. Venous reconstruction after resection is unnecessary in chronic cases without a history of an edematous leg. Radiotherapy is an important adjuvant for local control when the surgical margins are close or positive. The role of chemotherapy in systemic management remains unclear.