What happened, in summary

This 83-year-old woman first presented with changes in the right nipple. Biopsy showed Paget disease with a 3 mm focus of invasive ductal carcinoma that was ER-alpha 90%, PR 80%, and HER2-negative. Because she had severe tricuspid valve regurgitation and chronic atrial fibrillation, she hoped to avoid surgery, so anastrozole 1 mg daily was started. In 2021, surveillance mammography found a new lesion 1 cm from the nipple. Core biopsy showed a moderately differentiated invasive carcinoma with apocrine features that was ER-negative, PR-negative, and HER2-negative. She underwent mastectomy. Pathology showed a 0.4 cm residual focus of ER/PR-positive, HER2-negative invasive ductal carcinoma in the nipple and a separate 1.1 cm invasive apocrine carcinoma arising in atypical apocrine adenosis. Sentinel lymph nodes were negative, staged pT1c pN0(sn). The retroareolar tissue also contained classic follicular lymphoma: B cells were CD20-positive, PAX5-positive, BCL6-positive, and BCL2-positive, with clonal IgH rearrangement and IgH::BCL2 translocation. Imaging showed no disease outside the breast, so the lymphoma was Stage Ie and observed. Anastrozole was stopped 10 months after surgery. Two months later, routine screening found a 1.8 cm moderately differentiated invasive apocrine carcinoma in the opposite breast, again ER-negative, PR-negative, and HER2-negative, with high-grade apocrine DCIS. She had simple mastectomy with negative sentinel node biopsy, pT1c pN0(sn). No chemotherapy or radiation was recommended. As of September 2025, 3 years later, she was alive with no recurrence of either carcinoma or lymphoma. The case also links aromatase-inhibitor exposure to a later shift toward androgen-responsive apocrine breast tumors, while keeping the hereditary germline cancer panel negative.