Metastatic Signet Ring Cell Adenocarcinoma Manifesting as Chronic Leg Pain

Signet ring cell carcinoma, a type of gastrointestinal system-related cancer, rarely metastasizes to the skeletal muscle. We present signet ring-cell carcinoma in a 28-year-old man who presented with left lower extremity pain and swelling. Imaging showed thickening of the distal esophagus, intestines, and bladder wall. Endoscopy revealed friable gastric mucosa and stenosis in the ascending colon, but biopsies were unrevealing. Leg muscle biopsy showed metastatic adenocarcinoma with focal signet ring features. Carcinoembryonic antigen and cancer antigen 19-9 were elevated. A gastrointestinal primary tumor was suspected. Our case urges clinicians to consider this rare cancer in patients presenting with skeletal muscle mass.