Work

Mass-forming Acellular Keratin Masquerading as “Residual Tumor” in a Metaplastic Breast Carcinoma with Pathologic Complete Response: A Case Report

Year: 2026

Type: article

Abstract: Metaplastic carcinoma is an uncommon subtype of breast carcinoma which often shows a pathologic incomplete response to neoadjuvant chemotherapy. We report a metaplastic breast carcinoma with squamous differentiation showing pathologic complete response following neoadjuvant chemotherapy. The tumor bed showed keratinous debris without any viable residual tumor. Post-treatment, the acellular keratin persisted as a mass on physical exam and ultrasonography, suggesting an incomplete clinical response and resulting in clinical and pathologic discordance. This report expands the spectrum of histological findings in breast carcinoma with clinical and pathologic discordance in the neoadjuvant setting.

Source: International Journal of Surgical Pathology

DOI: 10.1177/10668969261426536

Authors: Angelica MS Caindec, Linda C. Hanley, Kamaljeet Singh

Institutions: Women & Infants Hospital of Rhode Island, Brown University

Language: English

Topic: Breast Lesions and Carcinomas

Subfield: Pathology and Forensic Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $4,150