265. Comparison of Response to Neoadjuvant Aromatase Inhibitors Between Luminal a and B Breast Cancer Subtypes

with an appropriate diagnostic tool is a clinical concerning matter. Different modalities have been proposed with different efficacy such as breast duct endoscopy, Breast CT scan and various biopsy techniques. In this study we tried to investigate the role of core needle biopsy (CNB) as a fast and easy diagnostic procedure in plasma cell mastitis, considering open biopsy as gold standard. Material and methods: To evaluate the efficacy of CNB in diagnosis of plasma cell mastitis and differentiate it from a malignant lesion certainly, we analyzed the clinical and histopathological data of 76 patients with primary diagnosis of plasma cell mastitis from January 2001 to December 2008. All of them had a palpable mass in breast and their primary diagnosis was obtained by means of CNB. 48 out of these 76 patients (63.15%) who had undergone incisional or excisional biopsy as diagnostic or therapeutic option afterwards were included in the study. Results of definitive pathologic examination were compared with CNB results. Results: Of 48 patients with median age of 34 years (range 22-48), 27 (56.25%) underwent excisional biopsy and 21 (43.75%) underwent incisional biopsy. Tuberculosis in 3 patients (6.25%) and Breast cancer in 8 patients (16.66%) were confirmed after pathologic examination of the surgical specimen. The average follow-up period was 54 months. There were 9 chronic wound with delayed healing and 10 chronic fistulae during postoperative period. The rate of chronic wound in excisional and incisional biopsy group were 7.4% and 33.33% and rate of fistulae formation for them were 7.4% and 38.09% respectively. Conclusions: The results show that diagnosis of plasma cell mastitis which is obtained from CNB of a breast mass is not reliable. We suggest performing surgical biopsy in all above-mentioned patients. Excisional biopsy prevents delayed treatment in malignant lesions or inappropriate treatment in tuberculosis. Besides it usually is the only therapeutic procedure required for plasma cell mastitis.