[Suspicion of malignant melanoma in a lymph node caused by tattoo pigment].

This is a case report of a 31-year-old woman going through cancer staging after being diagnosed with breast cancer. During sentinel node dissection, a remarkable dark lymph node was found. Metastatic malignant melanoma was suspected, but with careful histochemical examination the lymph node was confirmed to only contain tattoo pigment. The patient had rather large tattoos on her arms, which was suspected to be the source of the ink in her lymph nodes. Tattoo pigment can complicate cancer staging, and it is important to know this rare effect on lymph nodes when dealing with cancer staging.