Invasive Ductal CA : Inflammatory Response
Some infiltrating ductal carcinomas have a prominent inflammatory infiltrate composed mainly of mature lymphocytes admixed with plasma cells, histiocytes, neutrophils, and mast cells. The lymphocytes are predominantly CD8+ cytotoxic suppressor T-cells. Medullary carcinomas or infiltrating ductal carcinomas with medullary features show a predominance of plasma cells.
A small percentage of nonmedullary breast carcinomas also show lymphoplasmacytic infiltrate. These tumors are usually poorly-differentiated and have circumscribed margins. They are usually ER negative/PR negative. In the molecular classification of breast carcinoma based on gene expression patterns, they belong to the basal-like group.
The tumors that fit the description of medullary carcinomas of the breast have better prognosis. The favorable outcome has been linked to the host response consisting of intense lymphoplasmacytic reaction. The impact of inflammatory response on the prognosis of non-medullary invasive ductal carcinomas is not clear. Various studies have reported better prognosis, no change, or worse prognosis.