Intracystic papilloma of the breast forming a giant cyst.

Intracystic tumors of the breast prove to benign more often than malignant, and most intracystic lesions are benign papillomas. Generally, the cyst with intracystic papilloma of the breast is small, and there are few cases of intracystic papilloma of the breast forming a giant cyst in the literature. We report the case had the intracystic papilloma of the breast with a giant cyst (diameter of 15.0 cm). Imaging examinations showed two intracystic components in the cyst, and suggested that they were malignancy. Cytological examinations revealed no malignant cell. In spite of many aspirations of the cyst fluid, the size was not changed finally. The surgical resection was performed, and histological examination revealed two intracystic papillomas. In review of the literatures, it is difficult to distinguish between intracystic papilloma and intracystic papillary carcinoma by imaging or cytologic examinations preoperatively. Surgery should be recommended to confirm diagnosis and treatment.