Abstract
A 42-year-old woman was admitted to the hospital because of a huge tumor, 11×15 cm in size, of the left breast with bloody discharge from the skin erosion. Computerized tomography and echography revealed a large cystic mass with a small solid tumor beside it. About 400 ml of old blood was aspirated by fine needle aspiration cytology but no malignant cell was observed. Frozen section examination following excisional biopsy showed the tumor to be malignant. Modified radical mastectomy was performed. Histologically, almost of the mass lesion was occupied with the cyst with true wall, and the solid tumor beside the cyst is invasive ductal carcinoma. The carcinoma invaded beyond the cyst wall, in which vessels were exposed into the cyst. It is considered that the bleeding from these vessels resulted in the formation of such large cystic mass.
The relative risk of developing subsequent breast cancer among women with breast cystic disease is approximately two to four times that in women without breast cystic disease. However, this is a very rare case of breast cancer concomitant with huge cyst due to the rupture of the tumor vessels into the cyst.
