Phyllodes tumors of the breast are rare, accounting for 0.3-0.5% of breast neoplasms. The tumors are divided into benign, borderline and malignant lesions according to the histological features. Phyllodes tumors are commonly recurrent, so wide local excision is considered as the only curable treatment. Therefore, an accurate pre-operative diagnosis can reduce recurrence after treatment. On ultrasonography, benign phyllodes tumors are generally seen as well circumscribed, oval shaped, hypoechoic or isoechoic masses, and occasionally, internal clefts or cystic portions are visible. Borderline or malignant phyllodes tumors tend to be larger and more highly categorized than benign tumors. Most phyllodes tumors present as a palpable mass, which usually require sonographic evaluation with a core biopsy; however, the reported diagnostic accuracy is approximately 60 percent, due to limitations of the histological features. Thus, a follow-up ultrasonographic evaluation is essential after a core biopsy and a phyllodes tumor should be considered in cases of growth occurring after a benign biopsy.