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Heavy metals in tattoo ink can be deposited in axillary lymph nodes, mimicking malignant calcifications. High-density foci in axillary lymph nodes can be the sequelae of a benign or malignant process.
A 34-year-old female presented with left breast discomfort. Mammography showed suspicious left breast calcifications for which biopsy revealed multicentric ductal carcinoma in situ. Imaging also showed high-density foci in her left axillary lymph nodes suspicious for nodal metastases; however, biopsy of the lymph nodes found the high-density foci to be pigment-laden histiocytes from tattoo ink metallic deposits.
High-density foci in axillary lymph nodes on mammography can be evidence of calcifications or metal deposits and can be the manifestation of a benign or malignant process. Thus, this finding may warrant additional diagnostic workup (including mammography, ultrasound, and possibly biopsy) and correlation with clinical history.
A tattoo is a form of art in which pigment is deposited into the skin. The designs are eclectic, and the practice has become mainstream. In recent years, tattoos have become equally common between men and women.1 A 2006 report found that 24% of people in the United States have tattoos.1
We present a patient with ductal carcinoma in situ (DCIS) of the left breast who was radiographically found to have high-density material in bilateral axillary lymph nodes that was proven to be the result of tattoo pigment.
A 34-year-old premenopausal female presented with a 12-month history of intermittent focal discomfort in the inferior left breast. She had no significant medical or surgical history or family history of breast cancer. Menarche was at the age of 12, she was gravida 1 para 1, and her age at the time of the pregnancy was 28 years. She had an intrauterine device and reported a history of irregular periods. Physical examination revealed a <1-cm tender palpable lump in the lower left breast at 6 o'clock. No nipple inversion, abnormal nipple discharge, skin changes, or discoloration was present. The patient had no palpable axillary or cervical lymphadenopathy. She had numerous tattoos along her trunk and arms, including her left wrist.
Diagnostic mammogram demonstrated suspicious fine linear branching calcifications with a segmental distribution in the left breast at 6 o'clock corresponding to the palpable abnormality (Figure 1); these calcifications were considered American College of Radiology BI-RADS (Breast Imaging Reporting and Data System) category 4, and core needle biopsy of the calcifications was recommended. We observed high-density material within the nodes in the left axilla that manifested as hyperechoic foci within the left axillary nodes on ultrasound (Figure 2). The original tomosynthesis projection images showed similar findings in the right axillary lymph nodes. Of note, the axillary lymph nodes were not enlarged and did not demonstrate focal or diffuse cortical thickening. Bilateral breast magnetic resonance imaging with contrast demonstrated non–mass-like enhancement within the lower left breast (Figure 3) and unremarkable lymph nodes (Figure 4).
Stereotactic vacuum-assisted biopsy of the left breast calcifications revealed DCIS of intermediate nuclear grade. Ultrasound-guided core needle biopsy of a left axillary node was negative for malignancy. The patient underwent bilateral mastectomy with left sentinel lymph node biopsy. Because of the high risk of recurrent breast cancer and for cosmetic reasons, the patient opted for double mastectomy. Histopathology of the left sentinel lymph node demonstrated normal lymphoid tissue with pigment-laden histiocytes, negative for malignancy (Figure 5).
High-density foci within axillary lymph nodes on mammography can represent benign or malignant processes and warrant additional evaluation to exclude metastatic disease in the setting of a suspicious abnormality in the breast.2,3
Coarse, dense calcifications in axillary nodes can be caused by granulomatous diseases such as sarcoidosis, tuberculosis, or histoplasmosis. Other benign causes include fat necrosis or lymph node talcum deposition in patients with a history of inhalation or intravenous drug abuse.2-4 Gold salt deposits from intramuscular injections for treatment of rheumatoid arthritis can appear as high-density foci in nonenlarged lymph nodes.2
Metastatic breast cancer is the most common cause of malignant axillary lymph node calcifications. These calcifications are usually ipsilateral and may even occur without visualized calcifications within the breast tissue.4 Amorphous and peripherally located calcifications can be seen with metastatic thyroid or ovarian papillary carcinoma, secondary to the presence of psammoma bodies.2-4
Punctate radiopaque foci similar in appearance to calcifications can also represent tattoo pigment deposition in draining lymph nodes.2 Tattoo ink usually contains a heavy metal dye that varies according to the desired color. Iron and carbon are typically used for black, mercury sulfide for red, cobalt aluminate for blue, cadmium sulfide for yellow, and chromium oxide for green.5,6 Although highly suspicious for metastatic disease, nodal pigmentation may also represent tattoo pigment in a draining lymph node in patients with metastatic melanoma.7 Our patient had tattoos along her medial left wrist, along her back, and on both sides of her chest wall. Typical lymphatic drainage for the medial aspect of the upper extremities and portions of the anterolateral and posterior chest wall is to the axillary lymph nodes.8
To the best of our knowledge, radiographically high-density material in breast specimens resulting from tattoo ink was first reported in 1989 by Lager et al.9 In their case, tattoo pigment was used to orient an excised tissue specimen before mammography. The specimen revealed high-density foci caused by the tattoo pigment.9 In 2004, Honegger et al published a case of tattoo pigment mimicking nodal calcification.10 Fine-needle aspiration cytology of the axillary lymph node showed scattered benign lymphocytes and abundant obscuring black pigment with no calcifications; however, no core biopsy was performed. Matsika et al presented a case report in 2013 in which a core biopsy was performed, and, similar to our findings, no true calcifications or evidence of malignancy was present.5
High-density foci in axillary lymph nodes by mammography can be evidence of calcifications or metal deposits and can be the manifestation of benign or malignant processes. Thus, this finding may warrant additional diagnostic workup (including mammography, ultrasound, and possibly biopsy) and correlation with clinical history.
The authors have no financial or proprietary interest in the subject matter of this article.
This article meets the Accreditation Council for Graduate Medical Education and the American Board of Medical Specialties Maintenance of Certification competencies for Patient Care and Medical Knowledge.