Abstract
RATIONALE: Adenoid cystic carcinoma (AdCC) is a rare malignancy of the breast with a low Ki-67 index and good prognosis. Owing to the rarity of breast AdCC, the misdiagnosis rate is as high as 50%, and there is no consensus or recognized guidelines for the treatment of this disease. Therefore, it is necessary to conduct a detailed clinical and pathological analysis in combination with a literature review to improve our understanding, diagnosis, and treatment of the disease. METHODS: A 68-year-old woman sought medical attention due to a recently increasing mass in the breast. The left breast mass was 1.3 cm × 1 cm in size. We analyzed the morphology, immunohistochemistry, and molecular characteristics of the tumor removed by surgery, and reviewed relevant literature. DIAGNOSES: Solid basal AdCC of the breast. INTERVENTIONS: We performed biopsy, immunohistochemistry and molecular testing on surgical resection specimens. OUTCOMES: Combining morphological and immunohistochemical features, it is consistent with solid basal AdCC of the breast, and Fish detected MYB gene break. LESSONS: Due to the high misdiagnosis rate of AdCC, accurate histopathological diagnosis is particularly important. At present, breast conserving surgery and local tumor resection are mainly used for the treatment of breast AdCC, and postoperative adjuvant radiotherapy is feasible.