Metachronous bilateral triple-negative breast cancer associated with neurofibromatosis type 1: A case report.

The present study reports a case of metachronous bilateral breast cancer associated with neurofibromatosis type 1 (NF1). A 67-year-old female, who had undergone a radical mastectomy of the left breast 34 years ago due to breast cancer, presented with a tumor of the right breast. The clinical stage of the original breast cancer was T2N0M0 stage IIA and adjuvant chemotherapy had not been not administered. With regard to the right-sided breast tumor, on physical examination, multiple neurofibromas and café-au-lait spots were found to be scattered over the skin. A 2-cm tumor was palpable. The preoperative histopathological diagnosis of the right-sided breast tumor was invasive ductal carcinoma, T2N0M0 stage IIA, with negative results for hormone receptors and human epidermal growth factor receptor 2. The patient underwent a modified radical mastectomy and axillary node dissection, and received adjuvant chemotherapy. The bilateral tumors were similar in histology and immunophenotype, each being histological grade 3, triple-negative and with a basal-like subtype. Based on a literature review of 90 breast cancers in 84 patients with NF1 (84 patients, 90 breasts), younger age onset, advanced clinical stage and hormone receptor negativity were characteristic features. Bilateral cancer occurred in 8.3% of patients and was characterized by ER negativity, earlier stage and younger age compared with patients with unilateral cancer.