Non-small cell lung cancer with distal cutaneous metastases in a patient with a previously treated colorectal carcinoma.

Cutaneous manifestations of visceral carcinomas are scarce, occurring in around 0.7-12% of internal malignancies. Lung cancer is one of the most common sources of skin metastasis, particularly in male patients. We present a case of cutaneous metastasis in a man with concurrent lung lesions and a previously treated colorectal carcinoma. Immunohistochemistry markers for both skin and lung lesions were strongly positive for carcinoembryonic antigen and cytokeratin 20, suggesting an intestinal primary tumour. However, colonoscopy excluded new and metastatic bowel lesions. After multidisciplinary team meetings, which reviewed the clinical, radiological and immunohistochemistry findings, it was concluded to be a non-small cell lung cancer with skin metastasis. This case presented an interesting diagnostic challenge, and highlighted the importance of cross-specialty liaison and investigation to reach the correct diagnosis.