Metastatic Colon Cancer

A 78-year-old man with a history of asthma, coronary artery disease, chronic obstructive pulmonary disease (COPD), and recently diagnosed prostate cancer was admitted to the medical ICU with exacerbation of COPD. The obtunded patient was unable to provide a history. A 4 × 6-cm firm nodule of unknown duration was noted over the right upper quadrant of the patient’s abdomen. There were no other cutaneous lesions. Drs Yelva Lynfield, Karen Kim, and Steve Oberemok of Brooklyn, NY, write that a skin biopsy revealed poorly differentiated adenocarcinoma predominantly in the vascular spaces. Immunohistochemical studies showed no immunoreactivity with prostate markers; however, strong immunoreactivity with carcinoembryonic antigen consistent with primary carcinoma of the colon was demonstrated. A large retrospective study found that cutaneous metastases were the presenting sign in 6.4% of patients with visceral malignancies.¹ Eleven of 18 patients with primary colon and rectal cancer presented with local cutaneous metastasis. The investigators also noted that most skin metastases present as nodules. The histologic pattern of cutaneous metastatic disease may be specific or nonspecific. Immunohistochemical markers are valuable in identifying the site of the primary malignancy.² After 5 weeks in the ICU, this patient died of complications from his chronic medical conditions.