Atypia Involving Fibroadenomas: Outcomes and Upgrade Rates.

Area of Science:

• Breast pathology
• Oncology
• Radiology

Background:

• Fibroadenomas (FAs) with atypia are uncommon breast lesions.
• Current management guidelines for FAs with atypia diagnosed via image-guided biopsy are lacking due to limited data on surgical upgrade rates.
• Consequently, surgical excision is the common management approach.

Purpose of the Study:

• To determine the surgical upgrade rates of fibroadenomas (FAs) involving atypia, including atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and lobular carcinoma in situ (LCIS).
• To evaluate the need for surgical excision in cases of FAs with atypia.

Main Methods:

• A retrospective study of 32 cases of FAs with atypia diagnosed via image-guided biopsy between January 2014 and April 2023.
• Exclusion of cases with incidental atypia adjacent to, but not involving, FAs.
• Analysis of surgical upgrade rates to ductal carcinoma in situ (DCIS) or invasive malignancy.

Main Results:

• Out of 1736 FAs, 32 cases (1.8%) involved atypia (43.8% ALH, 28.1% ADH, 18.8% LCIS).
• 81.3% of cases underwent surgical excision.
• A 3.8% upgrade rate to low-grade DCIS was observed; no cases upgraded to invasive malignancy. No malignancies were found at biopsy sites in patients who omitted surgery.

Conclusions:

• Radiologic-pathologic concordant FAs with atypia demonstrate a low upgrade rate of 3.8%.
• Multidisciplinary review is recommended for these lesions.
• Further multi-institutional studies are required to establish definitive management guidelines for atypia involving FAs.