Abstract
Skeletal muscle metastases are very rare events in colorectal carcinoma. By contrast, dermatomyositis is an idiopathic inflammatory myopathy with characteristic cutaneous manifestations and a well-recognized association with several human malignancies and, among others, colorectal cancer. Here, we report the case of a 71-year-old woman with paraneoplastic dermatomyositis followed by the development of a metastatic colon cancer. Interestingly, this patient developed multiple skeletal metastases which were preceded by the worsening of systemic symptoms of dermatomyositis. This observation suggests that, while muscle tissue is usually resistant to the development of tumor metastases, the inflammatory and immune response which characterizes and boosts paraneoplastic myopathy may represent a favorable soil for tumor cell invasion and metastasization to skeletal muscles.
Highlights
Colorectal carcinoma is a very common malignancy in humans, and the liver is the most frequent site where colorectal cancer metastases occur, followed by lung, peritoneum, and bone
Several mediators released by muscle cells may account for the rarity of metastatic nodules in this tissue, including cytokines with antitumor activity, such as TNFα, TGFβ, lymphocyte infiltrating factor, interferon γ, lactic acid, and proteolytic enzymes like plasminogen activator inhibitor [7]
It has been suggested that small molecules present in conditioned medium of muscle cells and, among others, natural agonists of A3 adenosine receptor exert an inhibitory effect on the growth of several human tumor cell lines [7, 8]
Summary
Skeletal muscle metastases are very rare events in colorectal carcinoma. We report the case of a 71-year-old woman with paraneoplastic dermatomyositis followed by the development of a metastatic colon cancer. This patient developed multiple skeletal metastases which were preceded by the worsening of systemic symptoms of dermatomyositis. This observation suggests that, while muscle tissue is usually resistant to the development of tumor metastases, the inflammatory and immune response which characterizes and boosts paraneoplastic myopathy may represent a favorable soil for tumor cell invasion and metastasization to skeletal muscles
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