Question 1:
A 74-year-old woman presents with a complaint of a roughened area on the left chest. She has a history of invasive ductal carcinoma of the left breast 2 years prior, status post mastectomy with neoadjuvant Herceptin and radiation therapy. The left chest showed a well-demarcated geometric rectangular hyperpigmented patch studded with multiple spiny keratotic papules (Figures 1-3). A 4mm punch biopsy was performed (Figures 4-5). A shave biopsy 2 months prior showed similar histopathology.
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Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Which of the following is the best diagnosis?