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I have gone through your case. In my opinion, your lesion should be biopsied as early as possible as you have a long-standing history of cutaneous cancer, and I fear it could be slow-growing skin cancer. I have two to three differential diagnosis.
1. Nodular squamous cell carcinoma.
2. Nodular non melanocytic melanoma.
3. Basal cell carcinoma.
The Probable causes:
1.Sun-exposed area.Investigations to be done:
2.White race and,
3 Past history of cancer
Need excision as early as possible.