Lobular Carcinoma in Situ (Breast)

Overview


Plain-Language Overview

Lobular Carcinoma in Situ (LCIS) is a condition affecting the breast tissue, specifically the milk-producing lobules. It is not a true cancer but rather a marker indicating an increased risk of developing breast cancer in the future. LCIS usually does not cause symptoms and is often found incidentally during biopsies for other breast abnormalities. The condition involves abnormal cells growing inside the lobules without invading surrounding tissues. While LCIS itself does not typically affect breast function, it signals a higher chance of developing invasive breast cancer later on. Regular monitoring and follow-up are important for managing health after an LCIS diagnosis.

Clinical Definition

Lobular Carcinoma in Situ (LCIS) is a non-invasive neoplastic proliferation of monomorphic, small, uniform cells confined to the terminal duct-lobular units of the breast. It arises due to loss of E-cadherin expression, leading to discohesive cells that lack adhesion, distinguishing it from ductal carcinoma in situ. LCIS is considered a marker of increased risk for developing invasive breast carcinoma, particularly invasive lobular carcinoma, rather than a direct precursor lesion. It is often multifocal and bilateral, reflecting a field effect in breast tissue. The clinical significance lies in its role as a risk indicator rather than a lesion requiring immediate surgical excision. Diagnosis is usually incidental during biopsy for other breast abnormalities or screening mammography findings.

Clinical Presentation


Diagnostic Workup


Pathophysiology


Treatments


Prevention


Outcome & Complications


Differential Diagnoses


Medical Disclaimer: The content on this site is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you think you may be experiencing a medical emergency, call 911 or your local emergency number immediately. Always consult a licensed healthcare professional with questions about a medical condition.

Artificial Intelligence Use: Portions of this site’s content were generated or assisted by AI and reviewed by Erik Romano, MD; however, errors or omissions may occur.

Analytics Disclosure: If you allow analytics cookies, Doctogenic uses Google Analytics, Microsoft Application Insights, and Microsoft Clarity to understand site usage, diagnose issues, review heatmaps and session replay recordings, and improve the service on pages where those tools are enabled. Clarity is not enabled on account, purchase, billing, checkout, Stripe-related, or admin pages. You can change this choice through Cookie preferences.

USMLE® is a registered trademark of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). Doctogenic and Roscoe & Romano are not affiliated with, sponsored by, or endorsed by the USMLE, FSMB, or NBME. Neither FSMB nor NBME has reviewed or approved this content. "USMLE Step 1" and "USMLE Step 2 CK" are used only to identify the relevant examinations.