New diagnostic approach to intracystic lesions of the breast by fiberoptic ductoscopy.

Intracystic tumors of the breast are uncommon and, at the time of ultrasonography and aspiration cytology, it is difficult to distinguish cancer from a benign tumor. The Fiberoptic Ductoscopy System (FDS) is an emerging technique allowing direct visual access to the ductal system of the breast. FDS was inserted through the cannulae into the cavity and we observed the intracystic tumors (3 intracystic papillomas and 2 intracytsic papillary carcinomas). The appearance of the malignant tumors was irregular, rough-shaped and they tended to bleed. On the contrary, benign tumors had smooth surfaces without bleeding. Cytological findings showed malignant cells in one out of two breast cancer patients. In addition, in the immunohistochemical study of resected tumor tissues from 5 patients, we observed positive reactions with anti-ErbB-2 antibody in 2 intracystic papillary carcinomas. In contrast, none of the histologically confirmed benign lesions (3 intracystic papillomas) gave positive results. In conclusion, the use of FDS as a non-invasive technique may provide valuable information.