Inflammatory Myofibroblastic Tumor 12 Years After Treatment for Synovial Sarcoma: A Case Report

Inflammatory myofibroblastic tumors (IMTs) are mesenchymal neoplasms most seen in the abdominopelvic region, lung, and retroperitoneum; and less commonly seen in virtually any other site. We report a case of two lower limb masses consistent with diagnosis of IMTs. This is a 39-year-old woman with a history of right lower extremity popliteal fossa synovial sarcoma diagnosed 12 years prior and treated with chemotherapy, surgery, and radiation. She presented with two new – one anterior and one posterior – right thigh masses. Biopsies of the lesions demonstrated low-grade inflammatory spindle cell lesions at both sites. Wide resection was performed for both masses and further characterization of the surgical specimens was most consistent with IMT. At follow-up, the patient is well with no signs of recurrence 19 and 7 months postoperative to the resection of the anterior and posterior thigh masses, respectively. This case represents the first reported IMTs occurring as late as 12 years after primary cancer treatment, and the first occurring after synovial sarcoma.