Early-stage HER2-positive breast cancer in neurofibromatosis type 1: a case report with literature review.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder associated with an increased risk of malignancies, particularly breast cancer at a younger age. We report the case of a 48-year-old woman with clinically diagnosed NF1 who presented with a left breast mass detected during routine screening. Physical examination revealed numerous café-au-lait macules and cutaneous neurofibromas distributed over the trunk and extremities. Imaging findings were classified as BI-RADS 4B-4C. Following intraoperative confirmation of malignancy, total mastectomy and sentinel lymph node biopsy were performed. Histopathological examination demonstrated HER2-positive invasive ductal carcinoma with associated ductal carcinoma in situ (pT1cN0M0, Stage IA), while all sentinel lymph nodes were negative for metastasis. The patient subsequently received adjuvant chemotherapy combined with trastuzumab. No recurrence or distant metastasis was observed during 21 months of follow-up. This case highlights the importance of early screening, individualized treatment, multidisciplinary management, and regular surveillance to optimize outcomes in patients with NF1-associated breast cancer.