Diffuse metastatic infiltration of a carcinoma into skeletal muscle

Skeletal muscle is one of the most unusual sites of metastasis from any mal ignancy. We report a patient with rapidly progressive contractures due to m etastatic infiltration of a carcinoma of unknown origin into the skeletal m uscle. This 61-year-old man presented with a 1-month history of rapidly evo lving. painful restriction of mobility of his right arm and his legs. Compu ted tomography showed diffuse metastatic nodules in ail muscles, particular ly in the hip abductors. Muscle biopsy revealed extensive infiltration of t he muscle with carcinoma cells.