Unusually large colon cancer cutaneous and subcutaneous metastases occurring in resection scars

Development of cutaneous metastases from colon cancer is a rare event, usually occurring in the setting of diffusely-disseminated disease and commonly carrying a dismal prognosis. Cutaneous and subcutaneous metastases in surgical scars occur extremely rarely, with only a few cases reported. We describe two cases of cutaneous metastases from colon cancer. A 62-year-old woman developed an 11-cm midline abdominal mass that slowly grew on the skin surface. The mass occurred at the scar site of her previous surgery performed 5 years prior for resection of a colon adenocarcinoma. A 46-year-old male presented with a subcutaneous 4.5-cm nodule in midline-abdominal scar, 3 years after resection of the primary colon cancer. These cases illustrate the pathological features and natural history of cutaneous metastases observed until the tumors have reached a very large size. Particular features of cutaneous scar metastases from colon cancer observed in our cases are a superficial pattern of spread, strong positivity for EGFR, low serum carcinoembrionic antigen, and long survival of the patients, possibly contributed to by the use of chemotherapy.