A 30-year-old woman presented for a diagnostic mammogram with a
palpable lump in her right breast. She was 9 weeks postpartum and
otherwise healthy. In the palpable region of concern, prominent
lactational changes were seen without any apparent mammographic
abnormality. Normal-sized bilateral axillary lymph nodes with punctate
hyperdensities were identified, simulating the appearance of intranodal
calcium (Figure 1). A chest computed tomography (CT) scan confirmed
hyperdense foci within bilateral axillary lymph nodes (Figure 2). The
patient underwent left axillary lymph node excisional biopsy. Histology
demonstrated subcapsular and paracortical deposits of dark-colored
pigment and multiple histiocytes containing internal black pigment
granules (Figure 3). There was no evidence of malignancy. Although no
tattoos were present on her anterior chest, many multicolor tattoos were
present on her back (Figure 4).
Dermal tattooing provokes predictable body responses, including
initial sloughing of the overlying epidermis, variable dermal
inflammation, and gradual assimilation of pigment into macrophages. Much
of the pigment is eventually carried into regional draining lymph nodes
(1). The composition of tattoo pigments is highly variable, but most
consist of various metallic ions including aluminum and titanium (2). If
sufficient quantities of pigment reach lymph nodes, punctate
hyperdensities mimicking intranodal calcific deposits can be seen
[FIGURE 1 OMITTED]
The differential diagnosis of axillary lymph node calcific deposits
includes both benign and malignant etiologies. Benign causes include
prior granulomatous disease, most commonly histoplasmosis, which
typically demonstrates a more coarse appearance (3). Fat necrosis is an
additional cause of calcified lymph nodes (4, 5). Gold deposits can
mimic intranodal axillary calcific deposits on mammography in patients
with rheumatoid arthritis who have undergone chrysotherapy treatment
(6). Of the malignant causes, breast cancer is the most common.
Malignant axillary nodal calcium can occur with an ipsilateral occult
breast cancer and can be seen in the absence of any suspicious calcific
deposits in the breast parenchyma (7).
Axillary lymph node calcium due to metastatic ovarian cancer and
papillary thyroid carcinoma has also been reported (8, 9). Lymph node
calcific deposits may also be seen in the setting of treated lymphoma
(4, 5). The broad differential diagnosis of axillary intranodal calcific
deposits seen on radiologic examinations emphasizes the importance of
histologic examination when a benign etiology is not apparent.
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
[FIGURE 4 OMITTED]
An additional clinical situation where intranodal tattoo pigment is
an important diagnostic consideration is with sentinel lymph nodes of
melanoma patients. Intraoperatively, a darkly pigmented lymph node is
concerning for metastatic disease but may represent a draining lymph
node containing tattoo pigment if a dermal tattoo is present in the area
of the primary melanoma (10). Histologic examination is warranted for
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A, Yeh IT. Tattoo pigment in sentinel lymph nodes: a mimicker of
metastatic malignant melanoma. Dermatol Online J 2005;11(1):14.
Amy R. Yactor, MD, Michael N. Michell, MD, Meghan S. Koch, DO,
Tyler G. Leete, MD, Zeeshan A. Shah, MD, and Brett W. Carter, MD
From the Departments of Radiology (Yactor, Michell, Leete, Shah,
Carter) and Pathology (Koch), Baylor University Medical Center at
Dallas. Corresponding author: Amy R. Yactor, MD, Department of
Radiology, Baylor University Medical Center at Dallas, 3500 Gaston
Avenue, Dallas, TX 75246 (e-mail: YactorA@gmail.com).