Breast: Occult Breast Cancer Occult Breast Cancer Occult Breast CancerDefinition: Lymph Node Metastases with an Unknown Primary SiteThe Primary Site is Never Identified in About 30% of CasesGenerally Represents a Poor PrognosisEvaluationFirst Steps:Physical ExamMammographyBiopsy Suspicious Lymph NodesIf Mammography Negative: Breast MRITreatment (If Imaging Still Unable to Identify Primary Lesions)Standard Treatment: Modified Radical Mastectomy (MRM)May Consider ALND with Whole-Breast Radiation Alone if Patient Wishes to Preserve Their BreastConsider Adjuvant Chemotherapy if Primary Lesion Still Unidentified