Purpose: to evaluate the concordance rate of ultrasound-guided core needle biopsy followed by excisional biopsy in palpable breast lumps, suggestive of fibroepithelial tumors.
Method: a retrospective study included 70 biopsies with a histological diagnosis of fibroepithelial tumor in 67 out of 531 patients with breast lesions submitted to ultrasound-guided core needle biopsy with a high frequency (7.5 MHz) linear transducer, using an automatic Bard-Magnum gun and a 14-gauge needle. Cases with a diagnosis of fibroepithelial tumor by core needle biopsy or excisional biopsy and with a diagnosis of fibrosclerosis were included in the study. The agreement between the two biopsy methods was assessed using the Kappa coefficient.
Results: excisional biopsy revealed 40 cases of fibroadenoma (57.1%), 19 cases of phyllodes tumor (27.2%), and 11 cases of fibrosclerosis (15.7%). The concordance rate for fibroadenoma was substantial (k = 0.68, 95%CI = 0.45 - 0.91), almost perfect for the phyllodes tumor (k = 0.81, 95%CI = 0.57 - 1.0), and moderate for fibrosclerosis (k = 0.58, 95%CI = 0.36 - 0.90).
Conclusions: the core needle biopsy is a minimally invasive method that has "substantial" to "almost perfect" concordance rate with excisional biopsy. Fibrosclerosis should be considered in the differential diagnosis of fibroepithelial tumors.