26th April 2024

A 50-year-old woman reports a new, painless lump in her right breast that she discovered four weeks ago.

A 50-year-old woman reports a new, painless lump in her right breast that she discovered four weeks ago. She has no family history of breast cancer. On examination, there is a 3 cm hard, immobile lump in the upper outer quadrant of her right breast. The overlying skin appears dimpled, and there is retraction of the nipple. An axillary examination reveals a firm, non-tender lymph node. 

Which is the most likely diagnosis?