Journal of Cancer Research and Treatment, 2017, Vol. 5, No. 3, 89-91 Available online at http://pubs.sciepub.com/jcrt/5/3/3 ©Science and Education Publishing DOI:10.12691/jcrt-5-3-3 Low Grade Malignant (Borderline) Phyllodes Tumor of the Breast: Case Report and Review of Literature Mazaher Ramezani 1 , Masoud Sadeghi 2,* 1 Molecular Pathology Research Center, Emam Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran 2 Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran *Corresponding author: sadeghi_mbrc@yahoo.com Abstract Phyllodes tumor (PT) of the breast is a rare disease usually presents as a large lump. The aim of this study was to report low grade malignant (borderline) PT of the breast in Kermanshah, Iran. A 55-year-old lady was admitted to the surgery ward with left breast mass since 2-3 months ago. In past medical history, the patient had left breast surgery due to fibrocystic change seven years ago. Grossly her specimen consisted in a piece of gray soft tissue measuring 10*8*4.5 cm with lobulated appearance and small cystic areas. In permanent diagnosis, the pathologist reported low-grade malignant (borderline) PT. Microscopically the tumor was composed of benign glandular elements and hypercellular spindle-shaped stroma. Mitotic index was 3/10 high power field (HPF). The border was well-circumscribed with satellite lesion. In conclusion, the diagnosis of borderline phyllodes tumor cannot be made only on age, the size of tumor, imaging or clinical features. Microscopic evaluation with evaluation of stromal cellularity, atypia, mitotic counts and border of the tumor is necessary for definite diagnosis and categorizing of this tumor. Keywords: phyllodes tumor, borderline, case report Cite This Article: Mazaher Ramezani, and Masoud Sadeghi, “Low Grade Malignant (Borderline) Phyllodes Tumor of the Breast: Case Report and Review of Literature.” Journal of Cancer Research and Treatment, vol. 5, no. 3 (2017): 89-91. doi: 10.12691/jcrt-5-3-3. 1. Introduction Phyllodes tumors (PTs) have an incidence of 1 per 100,000 women and account for only 0.5% of all breast malignancies [1]. PT of the breast is a rare disease usually presents as a large lump. In few cases, it is bilateral or multifocal [2,3]. These neoplasms generally present as unilateral painless, well-circumscribed, mobile breast masses in women 35 to 55 years old [4]. PTs are classified according to their biological behavior to benign, malignant and borderline [5]. Most PTs are benign (63–78%), with borderline PTs diagnosed in only 11–30% cases [6]. They are more prevalent in the Latin American, White and Asian populations [7]. The difficulty in distinguishing between PTs and benign fibroadenoma may lead to misdiagnosis. In fact, there are no characteristic features that clinically distinguish PTs from other breast cancers [8]. The aim of this study was to report low grade malignant (borderline) PT of the breast in Kermanshah, Iran. 2. Case Report A 55-year-old lady was admitted to the surgery ward on April 26 th , 2017 with left breast mass since 2-3 months ago. The mass was non-tender without discharge or nipple retraction, but with an increase in size according to the patient ' s report. In past medical history, the patient was menopause since eleven years ago and had left breast surgery due to fibrocystic change seven years ago. No significant drug or relevant family history was noted. On physical examination vital signs were stable. Large non-tender mass measuring 8*5 cm in pre areolar and upper part of the nipple and breast was present. The consistency was firm. Overlying skin showed mild telangiectasia. Axillary mass was not found. Figure 1. Gross specimen Laboratory data revealed that CBC (complete blood count), PT, PTT, Blood Sugar, Urea, Cr, AST, ALT, Alkaline phosphatase, Albumin, Bilirubin, Na, K and Ca