What happened, in summary

This 61-year-old woman found a hard, movable lump in the left breast during self-exam. Diagnostic mammogram and ultrasound showed a suspicious 2.4 cm mass at the 9 o’clock position, about 5 cm from the nipple. Biopsy revealed a primary neuroendocrine tumor of the breast. The tumor was strongly hormone-receptor positive, with ER 90% and PR 90%, HER2 1+ by immunohistochemistry, and a low Ki-67 of 8%. Additional staining showed GATA3 positivity and synaptophysin positivity, with chromogranin negative, supporting a breast primary neuroendocrine tumor. She underwent breast-conserving surgery and sentinel lymph-node biopsy. Final pathology showed a 2.8 cm breast primary neuroendocrine tumor with clear margins, and 2 left axillary sentinel lymph nodes were negative. The initial stage was Stage IIA, T2N0. After discussion, chemotherapy was not given. She received adjuvant radiation therapy, 42 Gy in 16 fractions plus an 8 Gy boost in 4 fractions. Anastrozole was prescribed for a planned 5-7 years, but she stopped after several months because of hot flashes and joint stiffness, then was lost to follow-up. About 2 years later, she returned with low back pain and severe hypercalcemia. Workup showed a 5.8 cm right upper-lobe lung mass, pathologic mediastinal adenopathy, and multifocal bone metastases involving ribs, spine, and scapula. Her back pain was caused by a T7 pathologic compression fracture. Bronchoscopy biopsy supported metastatic breast carcinoma. The recurrence occurred after early endocrine therapy discontinuation, a key part of the clinical timeline. She declined further cancer therapy, entered hospice, and died 1 month later.