Tattoo pigment interpreted as lymph node metastasis in a case of subungual melanoma.

We present a patient with subungual melanoma of the thumb who, during radioisotope-guided selective sentinel lymphadenectomy, was found to have black, hard lymph nodes at multiple axillary node levels. This finding was interpreted intraoperatively as clinical evidence of metastasis and a formal axillary dissection was carried out. Pathological examination of excised nodes failed to demonstrate metastasis but instead showed collections of tattoo pigment.