Primary lymphatic leiomyosarcoma presenting as a pelvic mass

Leiomyosarcoma (LMS) most commonly presents in the uterus or as a primary retroperitoneal mass. LMS metastases to the lymph nodes is exceedingly rare and to our knowledge there are no reported cases of lymphatic confined LMS.Case Presentation.A 72-year-old woman presented with intermittent lower abdominal cramping for about one year. Her surgical history was notable for a total abdominal hysterectomy (TAH) and bilateral salpingo-oophorectomy (BSO) for uterine fibroids, 25 years prior to presentation. She had no other notable medical history. She was found to have a 9 cm complex pelvic mass, extensive bulky pelvic and retroperitoneal lymphadenopathy and an enlarged right supraclavicular lymph node. Biopsies of the right supraclavicular lymph nodes, right para-aortic lymph nodes, and complex pelvic mass showed benign leiomyomatosis. Surgical debulking was performed including pelvic mass resection, and extensive lymphadenectomy. Final pathology confirmed metastatic LMS. The pelvic mass was found to be an enlarged obturator lymph node, positive for LMS. All visible disease was resected. She was started on an aromatase inhibitor postoperatively and has been disease free for 16 months.

This is a unique case of widely metastatic, yet lymphatic confined LMS in a patient with very remote history of TAH/BSO. The tumor responded well to surgical resection and aromatase inhibition. Although traditionally LMS does not involve lymphatic spread, this case demonstrates that LMS should remain in the differential when bulky lymphadenopathy is encountered. While there are rare cases of primary retroperitoneal LMS, this may be the first reported case of primary lymphatic LMS.