Metastatic involvement of skeletal muscle from gastric adenocarcinoma

Gastric cancer represents the fifth most common cancer diagnosis worldwide and the third leading cause of cancer-related mortality. In the USA, the overall 5-year survival rate is 31%, with distant disease nearing 5%. The most common sites of metastasis are the liver and peritoneum. Skeletal muscle involvement has been rarely reported. Since clinical and imaging findings overlap with primary sarcomas, a confirmatory biopsy is required for diagnosis. Prognosis remains poor with treatment options including palliative chemotherapy, radiotherapy and surgical resection. We report the case of a 57-year-old female presenting with extensive involvement of skeletal muscle 10 years after achieving remission. In addition to illustrating the refractoriness and poor outcomes associated with muscle involvement, this case and comprehensive review of the literature highlights important characteristics of disease biology and tumor genomics that warrant detailed discussion and exposition to a wider audience.