Objective  This study aims to analyze the clinical characteristics of primary breast carcinoma with signet-ring cell differentiation.

  Methods  Clinical data of 13 patients were analyzed retrospectively.These patients were suffering from primary breast carcinoma with signet-ring cell differentiation and admitted to Tianjin Medical University Cancer Institute and Hospital between 1999 and 2011.All patients were female with ages ranging from 38 years to 84 years; the median age was 53.The initial symptom in nearly all cases was a single breast mass.Modified radical mastectomy was identified as the treatment of choice.Radiation therapy, chemotherapy and endocrine therapy consisted the postoperative adjuvant therapy.

  Results  Histopathological examination after surgery confirmed the diagnosis for 13 cases of primary breast carcinoma with signet-ring cell differentiation.From this group, 1 case was in Stage 1, 8 were in StageⅡ, and 4 were in StageⅢ.Follow-ups were conducted for an average of 53.8 months, in which 6 patients were shown to have survived for more than 3 years, 5 for more than 4 years, and only 1 for more than 10 years.The 3-, 5-and 10-year survival rates were 46.2%, 30.8%, and 7.7%, respectively.

  Conclusion  Compared with the commonly observed infiltrating mammary duct carcinoma, primary carcinoma with signet-ring cell differentiation exhibits a lower incidence and higher invasiveness.Surgery, radiotherapy, endocrine and other comprehensive treatments should be administered actively after diagnosis.To date, no standard specific guideline has been recommended for clinical practice.Further clinical research relevant to this study should be conducted in the future.