Phyllodes tumor showing intracystic growth: a case report.

A phyllodes tumor often grows rapidly and occasionally contains microcysts; however, the tumor rarely shows a morphologically intracystic pattern. We experienced a rare case of a phyllodes tumor with a solid mass growing into the cyst. A 62-year-old female noticed a tumor in her right breast in January 1995. The tumor grew rapidly and she visited our out-patient clinic in February 1995. On physical examination, a 10 x 8 cm, well defined and movable mass with a smooth surface was palpated in the upper outer quadrant of the right breast. Mammography showed a large tumor shadow in the upper outer quadrant of the right breast without any microcalcification. Ultrasonography revealed a large cystic shadow with a low echoic lesion and solid component with heterogeneous internal echo in the cyst. Under general anesthesia, the tumor was widely excised. The resected specimen was 11.5 x 11 x 11 cm in size and the tumor was not invasive to surrounding tissues. Old bloody fluid was contained within the cyst. The gross appearance showed papillary process protrusions into a central cystic cavity. Histological examination revealed a borderline case of phyllodes tumor. Two years after the operation, she is doing well without any recurrence.