Thickening of skin and plaques on a man's nipples and areolas

A 68-year-old white man presents with 4 weeks of progressively worsening thickening of the skin and plaques on the bilateral nipple and areola. He has no personal or family history of warts or epidermal nevi and has not had hormonal therapy. On examination, he has hyperpigmented, verrucous plaques bilaterally, with no associated erythema or lymphadenopathy. Skin biopsy shows hyperkeratosis with ...