White man, 79, presented with a painless nodule on his left forearm arising in a tattooed area. He received the 5-cm tattoo more than 50 years earlier.

Figure 1: Low-power examination revealed abnormal keratin, severe dermal sun damage, tatoo pigment, and a cellular dermal neoplasm

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Figure 2: Basal keratinocyte dysplasia showing abnormal downward growth, abnormal surface keratin, and tatoo pigment within the papillary dermis

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Figure 3: High-power photomicrograph demonstrates cells with enlarged nuclei, one-to-two prominent nucleoli, cytoplasmic keratin, well-defined cell borders, and early pearl formation, features indicative of squamous differentiation

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Figure 4: Epitheliod and spindled squamous cells cells are seen infiltrating amongst dermal tatoo pigment

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ANSWER: What is your diagnosis? DS67