M 79, painless nodule, left forearm arising in a tattooed area

    A 79-year-old white homeless male of European descent presented to the dermatology clinic complaining of a painless nodule on his left forearm arising in a tattooed area. The 5-cm black tattoo had been placed more than 50 years earlier in the mid 1950s without complications. The patient's medical history did not reveal any prior neoplastic disorders and was significant only for chronic alcohol abuse.
    Physical examination revealed a raised, 1-cm nonulcerated skin nodule surrounded by a large black tattoo. There were no palpable lymph nodes in the axilla.
    A 4-mm punch biopsy was performed that revealed a poorly differentiated invasive squamous cell carcinoma. The tumor was completely excised with clear margins.
    Microscopically, a poorly differentiated carcinoma was present within a sun-damaged dermis, infiltrating amongst dermal tattoo pigment as single cells and nests (Figures (Figures114). Cytologically, the malignant cells displayed enlarged nuclei, one to two prominent nucleoli, abnormal cytoplasmic keratin, and intercellular bridges (desmosomes), typical of squamous differentiation (Figure 3). The overlying epidermis showed focal abnormal keratin and basal keratinocyte dysplasia (Figure 2).
    One year later, the patient remains free of any recurrence or metastasis.

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