In medicine, desmoplasia is the growth of fibrous or connective tissue. It is also called desmoplastic reaction to emphasize that it is secondary to an insult. Desmoplasia may occur around a neoplasm, causing dense fibrosis around the tumor, or scar tissue within the abdomen after abdominal surgery. Desmoplasia is usually only associated with malignant neoplasms, which can evoke a fibrosis response by invading healthy tissue. Infiltrating metastatic ductal carcinomas of the breast often have a scirrhous, stellate appearance caused by desmoplastic formations.