Expansive-Type Breast Cancer Needs Careful Tissue Sampling to Avoid Needle Tract Recurrence: A Case Report.

Needle tract recurrence in breast cancer is a rare form of recurrence, and there is limited data in the literature regarding its incidence. A 52-year-old nulliparous woman was referred to our hospital for the treatment of core needle biopsy-proven breast cancer. Mammography only showed a relatively well-defined mass. Ultrasound also showed a right breast mass, which displayed an expansive growth pattern. Magnetic resonance imaging of the main tumor showed low signals on T1-weighted images, high signals on T2-weighted images, and a washout pattern on dynamic studies. Consequently, the patient underwent a curative operation five weeks after the core needle biopsy. Postoperative pathological study showed atypical cells growing in a solid cribriform fashion, forming an expansive-type breast cancer measuring 17 mm, and isolated viable cancer cell clusters in the core needle biopsy-induced hematoma. Immunostaining showed estrogen and progesterone receptor positivity, human epidermal growth factor receptor type 2 negativity, and a Ki-67 labeling index of 20%. The patient received adjuvant radiotherapy to the conserved right breast, began taking an adjuvant aromatase inhibitor, and is scheduled to be followed up on an outpatient basis. Diagnostic physicians should be aware of the potential risk of needle tract recurrence associated with expansive-type breast cancers, especially in the case of core needle biopsies.