Lung cancer first discovered through a skin metastasis

What happened, in summary

A man in his mid-70s first developed pain in the buttock that travelled down his leg. Soon afterward, several painful purple skin lesions appeared on his torso. They were initially treated as infected cysts, but antibiotics did not help. By the time he saw a dermatologist, he had at least 6 firm skin and subcutaneous lesions, together with shortness of breath, poor appetite, and unintentional weight loss.

Biopsy of a skin lesion showed metastatic cancer. Further pathology, immunohistochemistry, and imaging indicated that the most likely primary site was a lung cancer in the left lingula, although the exact lung histology was not established.

The disease was already widespread. Cancer involved the skin and tissue beneath it, soft tissue and muscle, the sternum and other bone, areas of the neck and supraclavicular region, and both parotid glands. Treatment was therefore palliative.

He received 20 Gy of radiation in 4 treatments to the sternum to reduce pain. Liquid morphine was used as needed for pain and breathlessness. His condition continued to decline quickly. Two months after the dermatology visit, he was admitted with confusion and hallucinations. He then returned home with community palliative support. He died 4.5 months after the original dermatology referral. The short course reflected aggressive metastatic disease that first became visible through the skin.

The skin lesions were not a separate skin cancer; they were visible deposits from the internal lung malignancy. Their rapid increase paralleled his overall decline.