A case of solitary metastatic colon adenocarcinoma of the sternum: an unusual metastatic site

Colorectal cancer is a prevalent malignancy; it ranks as the third leading cause of cancer-related deaths globally. Despite the effectiveness of surgical intervention for primary tumors, ~30% of patients develop metastases, commonly in the regional lymph nodes, liver, lungs, and peritoneum. Bone metastasis is relatively rare but can occur, typically affecting vertebrae, pelvis, femur, and humerus. This study presents a 68-year-old patient with a history of locally advanced colon cancer who presented with a rapidly enlarging, painful sternal mass. Imaging and biopsy confirmed metastatic colon adenocarcinoma in the sternum. The patient was treated with radiation therapy, resulting in significant symptomatic relief and tumor reduction. This case highlights the rarity of sternal metastasis from colorectal cancer. Given the poor prognosis associated with skeletal metastases in colorectal cancer, this case emphasizes the need for vigilance in monitoring for atypical metastatic sites and the importance of tailored palliative care strategies.