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Nice, there's still the bonus question of other possible diagnosis for this. Will wait for that answer before closing the thread.

Second possibility: sclerosing adenosis

I could force that answer as a third possibility as a differential but the other answer in mind is a closer bet in morphology. Sclerosing adenosis would have calcifications and apocrine metaplasia missing. It's a close candidate.

Phyllodes tumor is the differential and damn I forgot to add histology to my search and now I can't unsee those images on google