Austin, D. C., Wu, J. S., Spentzos, D., Goldsmith, J. D., & Anderson, M. E. (2017). A Collision Tumor Involving a Primary Leiomyosarcoma of the Lower Extremity and a Metastatic Medullary Thyroid Carcinoma: A Case Report.. JBJS Case Connector, 7(4), e90.
Abstract
CASE: A 49-year-old man presented with a rapidly growing thigh mass. Histologic analyses demonstrated separate regions that were consistent with a collision tumor composed of a primary leiomyosarcoma and a metastatic medullary thyroid carcinoma. After responding to chemotherapy, the patient underwent resection of the tumor and a total thyroidectomy; he was disease-free 9 years after the diagnosis.
CONCLUSION: A wide diagnostic differential and thorough histologic analysis are necessary in patients presenting with neoplasms of the extremities. A leiomyosarcoma may be a hospitable location for metastatic disease, and the presence of a collision tumor should be considered when pathology findings are equivocal.