Paucity of muscle metastasis in otherwise widely disseminated cancer: a conundrum.

Despite widespread dissemination of cancer to multiple organs, muscle metastasis remains a rare occurrence. Limiting factors in this regard include, among others, repetitive muscle contraction, increased lactic acid, and decreased pH as well as protease metabolism. With the approval of hospital's research committee, a 10-yr review of histopathologic and imaging studies of patients diagnosed as having muscle metastasis was attempted. A review of the literature dealing with this phenomenon was also initiated. The review of the literature with reference to muscle metastasis highlighted its rare occurrence, which in turn correlated with our own 40-yr clinical experience (M.M.L.). As a potential target, muscle tissue remains an "infrequent soil" for metastasis because of its unique mechanical and metabolic qualities.