Lobular Carcinoma In Situ of the Breast. Clinical, Radiological, and Pathological Correlation.

Rationale and Objectives: The purpose of this study was to review the imaging findings associated with lobular carcinoma in situ (LCIS) of the breast with clinical and pathological correlation. Materials and Methods: A database search of patients treated at our institution from 2002 to 2011 identified 26 patients with LCIS associated with an imaging abnormality that had imaging available for review. LCIS was diagnosed by core-needle or excision biopsy. Patients subsequently underwent excisional biopsy, mastectomy, or clinical follow-up. Patients' mammography, ultrasonography (US), and magnetic resonance imaging (MRI) images were reviewed using the American College of Radiology Breast Imaging Reporting and Data System lexicon together with relevant clinical and pathology data. Results: The 26 patients had 31 imaging lesions that yielded a histological diagnosis of LCIS by image-guided core-needle biopsy (n = 29) or excision biopsy (n = 2). Twenty-eight of 31 (90%) lesions yielding LCIS had a mammographic abnormality, 3/20 (15%) lesions had a US abnormality, and 6/7 (86%) had an abnormality on contrast-enhanced MRI. Calcifications were the most common mammographic finding, seen in 25/31 (80%) lesions. All three lesions seen on US were masses; the majority was irregular, hypoechoic, avascular, and had posterior shadowing. Non-mass-like enhancement was seen in five (71%) lesions with an MRI abnormality. Two (7%) patients developed subsequent malignancy at follow-up. Conclusion: LCIS can have associated imaging abnormalities, most commonly grouped amorphous calcifications on mammography, a shadowing, avascular, irregular, hypoechoic mass on US, or heterogeneous non-mass-like enhancement with persistent enhancement kinetics on MRI.