Snap Shot A 53-year-old women presents with a mass in the right breast, which she claims was the result of trauma. Both the ipsilateral and contralteral axilla have no lyphadenopathy. Introduction Not a premalignant lesion Instead condidered a risk factor for breast cancer left alone, in-situ lobular carcinoma will become invasive in 20-30% of patients over a prolonged period of time(10-15 years) Contralateral cancer can either be ductal or lobular Majority are estrogen and progesterone positive Presentation See Breast Cancer General Evaluation Not readily visible on mammography It is often bilateral in the same quadrant need to do mammography of the contralateral breast at regular intervals Treatment High-risk patients should undergo excisional biopsy of the lesion Because of chance of becoming invasive in both breasts, patients should otherwise elect between very close follow up tamoxifen bilateral mastectomy especially if there is a family history