Tattoo pigment in sentinel lymph nodes: A mimicker of metastatic malignant melanomaDepartments of Pathology and Surgery, University of Texas Health Science Center1, and Methodist Hospital2, Cancer Therapy and Research Center3, San Antonio, Texas. firstname.lastname@example.org
Shylashree Chikkamuniyappa1, MD, Rolf Sjuve-Scott1, MD, PhD, Kris Lancaster-Weiss2, MD, Alexander Miller3, MD and I-Tien Yeh1, MD
Dermatology Online Journal 11 (1): 14
Tattoo pigment in the sentinel lymph nodes of melanoma patients represents a clinical challenge. If a tattoo is present in the area of the primary melanoma, the draining lymph nodes are likely to contain tattoo pigment, as well as being the site for metastatic deposits of melanoma. We describe a case report involving an elderly Caucasian male diagnosed with a Clark level-4 nodular malignant melanoma, wherein intraoperatively we encounter a darkly pigmented lymph node highly suspicious for metastatic disease. The patient had a tattoo in the vicinity of the malignant melanoma The specimen is sent for histological examination and is found to contain pigmented macrophages, but metastatic malignant melanoma is not identified. Histological confirmation of an enlarged pigmented node is essential before radical surgery is performed.
The incidence of malignant melanoma has increased over the last decades ; it constitutes 1-2 percent of all cancers but is responsible for two-thirds of the deaths attributed to skin cancer . Prognosis depends on tumor thickness, size, depth of invasion, location, ulceration, sex, and metastases. Sentinel lymph-node biopsy (SLNB) with lymphoscintigraphic mapping is now widely used for staging cutaneous melanomas. The regional lymph-node status is one of the most powerful predictors of survival and prognosis for patients with primary melanoma . SLNB is a minimally invasive procedure compared to regional lymph-node dissection. A complete dissection of the regional lymph nodes is recommended in cases of histologically positive lymph nodes . In patients with malignant melanoma who have tattoos, the tattoo pigment may clinically mimic metastatic disease. We present a case of this clinically important entity.
A 77-year-old man is referred to the dermatology clinic for evaluation of a pink nodular lesion of the right upper arm. The patient's past medical history is not contributory other than treatment for prostate cancer over 5 years prior. A prominent tattoo is located on the patient's upper arm in the area of the melanoma.
|Tattoo of the right upper arm. The tattoo is located adjacent to the excised malignant melanoma.|
Biopsy of the arm lesion reveals a 1.9-mm thick, Clark level-4 nodular melanoma. Definitive local therapy is provided in the form of a wide local excision with 2-cm margins and sentinel lymph-node mapping. Preoperative lymphoscintigraphy using technetium-99m demonstrates a single sentinel lymph node in the right axilla. Intraoperatively, a heavily pigmented sentinel lymph node is identified. The clinical impression is highly suspicious for metastatic disease and the tissue was sent to pathology for examination.
The sentinel node specimen consists of a portion of adipose tissue containing a grossly visible lymph node measuring 0.8 cm. On cut section, a fatty hilum is evident, and there is a thin rim of focal dark pigment. Frozen-section examination shows lymph node tissue with normal architecture. There are benign histiocytes within the lymph node, with black, nonpolarizable, coarse granules in the subcapsular and sinusoidal areas.
|Hematoxylin and eosin stained section of the excised sentinel lymph node. The black pigment is present with macrophages in the lymphoid tissue (Magnification × 100).|
Thorough examination of the slides shows no evidence of metastatic malignant melanoma. A report of benign pigment in the lymph node is reported to the surgeon. Review of paraffin embedded, formalin fixed sections by routine hematoxylin and eosin stain, as well as immunohistochemical analysis with MART-1 and HMB-45, shows no evidence of metastatic melanoma in the sentinel lymph node.
Tattooing is commonly performed in Western society and appears to be increasing in popularity . It is well known that tattoo pigment can migrate to the regional lymph nodes [6, 7]. The carbon particles mobilize and migrate through the lymphatics similar to melanoma cells and can be seen within the histiocytes or extracellularly . The size of the tattoo appears independent of the amount of lymph node pigmentation. Even if the patient has removed the tattoo by laser surgery or dermabrasion, the lymph node pigmentation does not disappear .
Pigmentation of lymph nodes is not pathognomonic of malignant melanoma. Black pigmented lymph nodes can occur by carbon deposits of tattoo pigment as in our case. It is prudent to seek a history of tattooing and tattoo removal in all melanoma patients. Other possible causes of pigmented lymph nodes are dermatopathic lymphadenitis with or without associated skin lesions , hemosiderin-laden macrophages after local trauma or surgery, and anthracitic pigment, especially in axillary or in hilar lymph nodes. Conversely, small deposits of malignant melanoma may not be grossly evident, or the amelanotic variant of melanoma may be present.
Several case reports have described tattoo pigment within lymph nodes in patients with melanoma. The first case report of tattoo pigment in a node was described in 1986 in a 60-year-old white male with Clark level-4 malignant melanoma of the left thumb with a pigmented axillary lymph node, which was later attributed to tattoos on the left upper extremity . The first report of tattoo pigment mimicking a positive sentinel lymph node in melanoma was made in 2001 in a 42-year-old male with an unknown primary and a pigmented axillary lymph node . The case described in this report is similar, but the primary is known to be adjacent to the tattoo.
Metastatic deposits of malignant melanoma in regional lymph nodes have a poor prognosis that worsens with the number of positive lymph nodes . The finding of a pigmented lymph node during lymph-node dissection may entice the overzealous surgeon to progress with radical surgery of the draining area. Extreme caution is recommended during surgery in patients with a tattoo or with a previous tattoo and presenting with malignant melanoma and pigmented lymph nodes. Histological and immunohistochemical confirmation of metastatic malignant melanoma in the sentinel lymph node is imperative before proceeding to complete regional lymph-node dissection. This decision would avoid unnecessary radical surgery and subsequent patient morbidity.
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