Invasive Lobular Cancer Arising in a Surgical Scar From Lumpectomy for a Previous Invasive Ductal Cancer of the Breast

We describe a case of pathology-proven invasive lobular breast cancer (ILC) arising in a scar over 15 years after lumpectomy for previous invasive ductal carcinoma (IDC). The tumor was detected on screening mammography as a new focal asymmetry at the scar site and confirmed at diagnostic mammography. Ultrasound demonstrated an irregular, shadowing, hypoechoic mass at the scar site. Ultrasound-guided biopsy revealed poorly differentiated invasive lobular carcinoma. MRI and CT showed an irregular mass with pectoralis muscle invasion. Multimodality imaging findings are described. This is the first case to our knowledge reporting multimodality imaging findings of a breast cancer developing at the site of a surgical scar that is histologically different from the originally resected cancer.