Primary signet ring cell carcinoma of the breast: A case report and literature review.

Primary signet ring cell carcinoma (SRCC) of the breast is a rare and aggressive type of breast cancer characterized by increased intracellular mucin production. It has a high risk of metastasis and poor prognosis compared to other breast cancer types. We report a 56-year-old woman with primary SRCC of the breast who first presented with retraction on her left breast.