Can tattoo ink spread to lymph nodes and resemble cancer metastasis on imaging?

A recent case report in Obstetrics and Gynecology described unnecessary lymph node removal after tattoo ink spread to nodes and appeared like cancer metastasis on PET/CT.

PET/CT, positron emission tomography combined with computed tomography, is frequently used to identify suspicious lesions, assess cancer spread after diagnosis and determine treatment response. It successfully assesses initial disease extent in many cancers. A radioactively labeled glucose molecule (18F-FDG) is injected intravenously and taken up by highly active cells, particularly cancer cells, producing images. In the recently reported case, tattoo ink produced a similar image and misled interpretation.

Tumor spread is the main factor guiding cervical cancer treatment. Very early disease favors surgery, whereas local and/or lymph-node spread generally leads to combined radiotherapy and chemotherapy instead. Accurate assessment is therefore vital.

The report concerned a patient with 14 separate tattoos extensively covering her legs, aged 32, with cervical cancer. Her tumor was confined to the cervix and surgery was planned. Preoperative whole-body PET/CT suggested spread to right and left groin lymph nodes, described as abdominal nodes around the uterus and ovaries. Surgery removed the uterus, fallopian tubes and 40 regional nodes. Laboratory examination found tattoo ink instead of cancer, revealing that the PET/CT appearance arose from ink.

This was the first cervical cancer case report identifying tattoo ink in lymph nodes, although cases in breast and skin cancers exist. Case reports do not rank highest for evidence or scientific value, but striking cases can usefully raise awareness. This report emphasizes that tattoo ink can falsely suggest nodal cancer spread, and physicians should consider this possibility when assessing cancer patients with tattoos.