Occult Breast Cacinoma (OBC) is very rare and always mistaken on diagnosis and theapy. Objective: For the reason of diagnosis and treatment early, Method: We observed 17 cas-es of OBC with the incidence of 0. 34% of all breast cancer in our hospital during the past 15 years. The first clinical sign is the axillary mass among the 17cases but the supraclavicular mass on-ly in one. The after operative specimen of breast was studied by serial section 8 of them (47% ) were found to be primary breast cancer. Resu...