If melanoma has spread deep into the skin, there is also a risk that it has metastasized (spread) to other areas of the body. The first sites to be affected are almost always the lymph nodes. The lymphatic system is a main component of the immune system and produces lymphocytes (the cells that fight disease). Unfortunately, this is also the pathway by which many malignant cancers also make their way from the initial location of a tumor to remote sites on the body. Identifying abnormalities in the lymph nodes is a critical step in determining the appropriate course of melanoma treatment. However, highly aggressive therapies may do more harm than good if cancer cells are assumed to be present when they actually aren’t.
Recent Case Highlights Potential for Error in Surgical Judgment
Medical researchers in San Antonio, TX have discovered that tattoo pigment may cause an initial misdiagnosis. The case in question involved a patient who had a tattoo on his upper arm near the site where the original melanoma skin tumor was removed. During an operation to biopsy a nearby node, a darkly pigmented substance was discovered in the tissue.
Although abnormal pigment in a lymph node is not a conclusive diagnostic characteristic of malignant melanoma, it is a potential sign that cancer is present. Fortunately, the surgical team sent the tissue sample to the pathology lab before proceeding with further surgery. There, it was discovered that the dark granules were simply carbon from the tattoo ink that had migrated through the body. The patient’s biopsy showed no signs that the melanoma had spread. This has happened with other patients also and is now a well-documented phenomenon.
Why is This Important?
The medical team reported this finding along with several other non-cancerous causes of abnormal pigmentation as a cautionary statement. They are concerned that some surgeons may proceed with radical surgery to remove lymph nodes without waiting for lab confirmation. The consequences of lymph node removal can be very unpleasant leading to ongoing complications for patients. This form of melanoma treatment should only be done when the biopsy confirms that it is necessary to prevent the further spread of cancer.
Pigment Migration is Common
Any patient who has a tattoo may have pigment that has traveled to a lymph node. Even if the tattoo was later faded with lasers or dermabrasion, this doesn’t remove the ink that has already migrated away from the tattoo site. Melanoma patients should advise their oncologist of any tattoo and where it is (or was) located on their body. This may reduce the risk of misdiagnosis and overtreatment based on visual inspection during exploratory surgery.