He initially thought his skin lesions were a result of shingles.

By Maggie O'Neill
Updated June 11, 2020

A new case report published Wednesday in the New England Journal of Medicine, features a middle-aged man with colon cancer who, despite visiting a dermatology clinic for a possible case of shingles, found out his cancer had actually spread to the surface of his skin.

The patient, a 59-year-old man with metastatic colon cancer, presented to the clinic following 10 weeks of experiencing painless, nonpruritic (not itchy) skin lesions that had formed around a large abdominal scar from a previous procedure to remove part of the man's colon three years earlier. The same incision had been used to perform a liver resection and a cholecystectomy (removal of the gall bladder), following the initial procedure.

According to the case report, "on examination, the lesions were firm, pink to violaceous [violet] in color, and vesicular-appearing." The man also presented with ascites, or abnormal buildup of fluid in the abdomen. Following a skin biopsy, doctors confirmed that the man's colon cancer had metastasized to his skin, and the patient was diagnosed with metastatic colon adenocarcinoma.

The occurrence of cancer spreading from a person’s internal organs to their skin—known as cutaneous metastasis—is rare, but it happens in 4–6% of colorectal cancer cases, according to Eric Johnson, MD, a colorectal surgeon at Cleveland Clinic. “It’s something you don’t see very often, [but] it can happen,” Dr. Johnson tells Health. More data, from a 2017 case report published in the Annals of Surgical Treatment and Research, puts the occurrence rate of cutaneous metastases resulting from colorectal adenocarcinoma at more like 3% of colorectal cancer cases.

Overall, the spread of cancer—referred to as metastasis—can happen through a series of steps, according to the National Cancer Institute (NCI). Initially, cancerous cells can grow into or invade nearby normal tissue. From there, those cells can move through the walls of nearby lymph nodes or blood vessels, where they can begin traveling through the lymphatic system and blood stream to other parts of the body. At any point in that process, those cancerous cells can stop at another location in the body, where they can form a tiny tumor and cause new blood cells to grow to create a blood supply for that new tumor.

But Dr. Johnson says the man in the NEJM case report experienced a different type of metastasis—specifically through tumor cells' contact with the man's outside skin. “If you operate on a colon cancer patient, you’re extracting the tumor. You can shed tumor cells that can implant [in the skin]," says Dr. Johnson. This is why, according to the NEJM case report, "the most common site of cutaneous metastases in colon adenocarcinoma is the abdominal skin, sometimes in or around surgical scars, as was seen in this case." The 2017 case study also explains that cutaneous metastases in colon cancer "generally occur within the first two years after resection of the primary colorectal tumor."

To prevent this spread, surgeons often use devices called wound protectors, which are put in place around wound openings during surgery to keep cancer from spreading from an organ to an incision. “They’re basically a thin, vinyl sleeve that is sterile,” Dr. Johnson explains. While most surgeons use these wound protectors, they aren’t used in every operation, says Dr. Johnson. He goes on to say that this could have been the reason the patient featured in the NEJM report developed the lesions on his stomach, which had spread from his colon cancer, but without a full patient history, nothing can be said for sure.

Unfortunately, the man featured in the NEJM case report received hospice care following his diagnosis but passed away five months presenting to the dermatology clinic.

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