[Accumulation of tattoo pigment in sentinel lymph nodes]

A 22-year-old woman presented with a superficial spreading melanoma on her right thigh (tumor thickness 1.0 mm, Clark-Level III). She also had decorative tattoos on her right ankle, right groin and coccyx. The staging results gave no indication for metastases. Intra-operatively, we observed a black pigmented lymph node highly suspicious for metastatic disease, but histological examination excluded metastatic spread and detected the accumulation of black pigment within the lymph node. Clinical differentiation between tattoo pigments and metastatic disease within lymph nodes is not possible. Histological confirmation of an enlarged pigmented lymph node is therefore essential before radical surgery is performed. Hence, accumulation of tattoo pigment within enlarged and pigmented lymph nodes needs to be included into the differential diagnosis and the documentation of decorative tattoos is important during skin cancer screening as well as during the follow-up of melanoma patients.