PS5-06-13: Carcinoma en Cuirasse

Abstract Carcinoma en Cuirasse We present the case of a 49 year old postmenopausal female with right breast stage IIIA (mpT2N2aM0) hormone receptor-positive and HER2-negative classic-type multifocal invasive lobular carcinoma who underwent a lumpectomy. She was treated with adjuvant dose-dense doxorubicin and cyclophosphamide, followed by paclitaxel (ddAC-T). She then received adjuvant radiation therapy which was followed by anastrozole. She discontinued anastrozole after losing her health insurance and had a local recurrence with biopsy-proven involvement of the dermis, carcinoma en cuirasse. The name, carcinoma en cuirasse, derives from its resemblance to a breastplate of armor. Following this, she underwent repeat radiation therapy to the skin, and was started on treatment with exemestane and palbociclib. She later switched from palbociclib to abemaciclib because of insurance issues, and continued exemestane and abemaciclib until progression of disease locally. Due to aversion to parenteral treatment, she was started on everolimus with exemestane instead. Unfortunately, she had further progression of disease locally at which time she agreed to treatment with fulvestrant and everolimus but had worsening of her carcinoma en cuirasse. It is likely that she had poor disease control because of intermittent compliance with all of her treatment. She most recently received repeat palliative radiation followed by capecitabine with improvement of her skin lesions. Citation Format: K. Rupani, P. Klein. Carcinoma en Cuirasse [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-06-13.