A 35-year-old Hispanic woman presents to her ob/gyn. She found a lump in her left breast during self-exam. She is also experiencing fatigue, headache, dyspnea on exertion, and body aches that don't resolve with use of nonsteroidal anti-inflammatory drugs.
Physical exam reveals a bulky, palpable mass in the left breast as well as axillary lymphadenopathy. Mammography and ultrasound confirm a 3-cm, oval mass in the upper outer quadrant of the left breast. The mass is noncalcified and has a well-defined tumor border. PET reveals metastatic spread, with multiple skeletal lesions as well as various lung lesion and liver lesions.
Genetic testing 5 years ago showed that she is a positive carrier for the BRCA1 gene mutation. Family history is positive for breast cancer in both her mother and maternal grandmother. Baseline mammography at age 30 was negative.
Needle biopsy is performed and reveals this immunohistochemical profile: cytokeratin negative; ER, PR, and HER2- negative; CK7 positive; S-100 protein positive, P53 positive; and PD-L1 expression positive. Histopathologic features are prominent lymphoplasmacytic reaction, syncytial growth pattern, poorly differentiated cells, high mitotic rate, and noninfiltrating microscopic circumscription of tumor borders.