Snapshot A 58-year-old woman presented to her primary care physician after a screening mammogram revealed calcifications in the left breast. Physical exam revealed no palpable breast lumps or axillary lymphadenopathy. Introduction Overview a neoplastic lesion confined to the breast duct a true premalignancy 50% develop into invasive ductal carcinoma if untreated login to view 1 more bullet Epidemiology Incidence 32.5 in 100,000 women represents ~20% of breast cancer diagnoses in the U.S. Risk factors increasing age nulliparity family history of breast cancer age ≥ 30 or older at birth of first child obesity ETIOLOGY Genetics inheritance increased risk with BRCA1 and BRCA2 mutations mutations 75% of DCIS is estrogen (ER)/progesterone (PR) receptor-positive Associated conditions Paget disease of the breast overlying breast skin changes that may occur in association with DCIS login to view 1 more bullet Presentation Symptoms asymptomatic Presentation typically no palpable mass on exam +/- nipple discharge +/- overlying breast skin crusting Imaging Mammography indications screening login to view 1 more bullet findings calcifications login to view 3 more bullets breast mass login to view 1 more bullet Ultrasound indications to guide biopsy if lesion is visible on US findings microlobulated mild hypoechoic mass with ductal extension Core or excisional biopsy indications diagnosis following detection of calcifications on mammogram login to view 1 more bullet findings proliferation of neoplastic cells within the mammary ductal system 11% will have findings of microinvasion Differential Lobular carcinoma in situ (LCIS) key distinguishing factor e-cadherin expression on histology login to view 1 more bullet Invasive carcinoma key distinguishing factor evidence of invasion on biopsy Treatment Medical radiation indications login to view 1 more bullet endocrine therapy indications login to view 2 more bullets modalities login to view 1 more bullet close follow-up and screening mammography indications login to view 1 more bullet Surgical lumpectomy indications login to view 3 more bullets followed by radiation login to view 1 more bullet mastectomy (typically bilateral) indications login to view 4 more bullets Complications Development of invasive carcinoma ~6% risk of recurrence of invasive carcinoma after DCIS treatment in both contralateral and ipsilateral breast Death Prognosis Excellent ~1.7-3% mortality in treated patients