Med Ultrason 2019, Vol. 21, no. 3, 232-238 DOI: Original papers Histopathological and tumor characteristics associated with false negative axillary ultrasonography results in breast cancer Merve Gursoy 1 , Gulten Sezgin 2 , Emine Merve Horoz 2 , Berna Dirim Mete 1 , Nezahat Erdogan 2 1 Izmir Democracy University, Faculty of Medicine, Department of Radiology, 2 Izmir Katip Celebi University Ataturk Training and Research Hospital, Department of Radiology, Izmir, Turkey Received 10.01.2019 Accepted 22.03.2019 Med Ultrason 2019, Vol. 21, No 3, 232-238 Corresponding author: Merve Gursoy, MD Izmir Democracy University, Faculty of Medicine, Department of Radiology, Mithatpaşa Cad. Aksel Gursel Bul. No:14 Karabağlar Izmir/Turkey Phone: +90 506 292 00 46 Fax: +90 232 260 10 04 E-mail: gursoymerve@yahoo.com Introduction For the correct staging of breast cancer and the im- plementation of appropriate treatment, o knowing the status of axillary lymph nodes is mandatory. In the deter- mination of lymph node involvement, physical examina- tion alone is not suffcient. Preoperative axillary ultra- sonography (AUS) with the sensitivity of 50-70% and specifcity of 87-95% is an indispensable part of staging [1]. When AUS is positive, sentinel lymph node biopsy (SLNB), which is an invasive procedure and requires additional costs, is passed and axillary lymph node dis- section (ALND) can be applied [2-4]. Thus. time and expense can be saved. However, as the false-negative rates of AUS (21%-48%) are not optimal, the demand for axillary surgery remains even if AUS is negative [5- 8]. Therefore, in many centers AUS is combined with fne needle aspiration biopsy (FNAB) and the accuracy is increased in the determination of metastatic axillary lymph nodes [9-11]. However, a negative FNAB still does not remove the necessity for SLNB. All this classic information started to change with the recent Z0011 Trial Abstract Aims: As the false-negative rates of axillary ultrasonography (AUS) (21%-48%) are not optimal, the demand for axillary surgery remains even if AUS is negative. The aim of this study is to determine the histopathological and tumor characteris- tics associated with false-negative AUS results. Materials and methods: Patients with normal AUS were divided into two groups as true-negative and false-negative according to the histopathology results of axillary lymph nodes. Two groups were compared in terms of age, histological grade of the primary tumor, histological size of the primary tumor, histological type, lymphovascular invasion (LVI), and ultrasonography BI-RADS classifcation of the primary tumor. The number of metastatic lymph nodes, size of the largest metastatic lymph node and the number of micrometastatic lymph nodes were also noted in the false-negative group. Results: There were 152 patients with normal preoperative AUS in the study group. The false-negative AUS rate was 20.4%. The incidence of invasive lobular carcinoma (ILC) and the mean tumor size was signifcantly greater in the false-negative group. Micrometastasis was present in 3 patients (3/31, 9.6%), the mean of the largest metastatic lymph nodes was 12.5 mm, the mean total number of malignant lymph nodes was 1.9 in the false-negative group. In 25/31 (80.6%) of the patients, there were less than or equal to 2 metastatic lymph nodes. The presence of LVI was higher in the false-negative group. There was no signifcant difference between the groups in terms of the other parameters. Conclusion: Before stating that the axilla is normal on ultrasonography, a careful evaluation should be made in patients with a mass >2 cm in size and/ or ILC diagnosis. Keywords: ultrasound; axilla; breast cancer; false negative DOI: 10.11152/mu-1875 Breast cancer: histopathological and tumor characteristics + false negative axillary US results