Tattoo pigment mimics positive sentinel lymph node in melanoma

A 42-year-old man with metastasizing melanoma from an unknown primary is presented. Initially a subcutaneous metastasis in the scapular region and a single lung metastasis were resected. Thorough examinations did not show any evidence of a primary tumour. From the site of the metastasis on the right scapular region, lymphoscintigraphy with axillary sentinel lymph node biopsy was performed. One axillary lymph node could be identified intra-operatively with the gamma probe as sentinel node. The sentinel node and 4 adjacent lymph nodes clinically showed black pigmentation. However, histopathological examination of the lymph nodes did not detect micrometastases. The pigmentation of the lymph nodes was due to decorative tattoos of the scapular skin.