Pathohistological and Immunohistochemical Analysis of Primary Invasive Ductal Breast Carcinoma with Signet-Ring Cell Differentiation- Differential Diagnosis, Prognosis and Complex Treatment

Primary signet ring cell carcinoma (PSRCC) of the breast is a rarely diagnosed neoplasm. We present a 76-year-old woman with a tumor formation in the left mammary gland, who has been self-medicating for a year. Pathohistological and immunohistochemical analysis proved rare primary invasive ductal carcinoma with focal (over 90%) signet ring cell differentiation, size 4 cm / 3.5 cm / 2 cm, moderately differentiated (G2). Complex oncological treatment, including radical mastectomy with axillary dissection, 6 courses of systemic adjuvant chemotherapy, radiotherapy of the chest wall and regional lymph nodes with TD 46 Gy and antiestrogenic hormone therapy, was performed. The diagnosis and the differential diagnosis of this rare tumor require precise pathohistological and immunohistochemical analysis. The prognosis and complex treatment depend on the clinical stage, hormonal and HER2 status. In locally advanced PSRCC of the breast with moderately differentiation, the combination of surgery, systemic chemotherapy, postoperative radiotherapy and antiestrogenic hormone therapy achieves long-term local tumor control without distant metastases for nearly two years.