Skeletal muscle metastases at sites of documented trauma

Hematogenous metastases to skeletal muscles have been reported to be rare. We report eight biopsy-proven cases of skeletal metastases occurring in sites of previously documented skeletal muscle trauma. We retrospectively reviewed MR imaging examinations obtained at a large orthopedic surgical oncology service from January 1994 through December 2000 for biopsy-proven metastases to skeletal muscles. Our retrospective review revealed 28 patients with biopsy-proven skeletal muscle metastases. Of these 28 patients, eight had a documented clinical history of previous trauma at the site of skeletal metastasis. Five of these eight patients underwent MR imaging before the development of a metastasis. MR imaging revealed a hematoma in three of the five patients and a partial muscle tear in two of the five patients. The hematomas and partial muscle tears were in the same skeletal muscle location in which the metastatic disease subsequently developed. Metastatic disease was documented by MR imaging and subsequent biopsy.

Skeletal muscle injury may alter muscle physiology and result in increased susceptibility to the development of metastatic disease at such sites.