Desmoplasia (also known as a desmoplastic reaction) is the term used by pathologists to refer to the growth of fibrous tissue around disease, usually cancer. However in dermatopathology, desmoplasia may also be seen with benign, as well as malignant, conditions.
Pathologists prefer the term desmoplasia over desmoplastic response/reaction as the process may be seen in normal tissue in which the appearance is not a response to the presence of pathology (see below). For radiologists, the use of the latter terms remains widespread as the presence of desmoplasia, for example in the mesentery, is usually indicative of an underlying tumor (although not necessarily on mammography - see below).
A desmoplastic reaction is a host response, characterized by a fibrotic connective tissue. It classically occurs due to the presence of malignant cells, and was initially described in breast cancer.
Histologically desmoplasia may involve very few cells or an abundance of them. The oligocellular form comprises a very low number of spindled tumor cells, thinly dispersed (usually as single cells) in a fascicular pattern, separated by bundles of sclerotic collagen, forming an extensive extracellular matrix. Whereas, the multicellular form demonstrates a large number of cells, including fibroblasts, vascular and immune cells, with a general lack of extracellular stroma .
In the skin, there are a large number of benign pathologies in which a desmoplastic reaction is well-recognized, e.g. melanocytic nevus .
More recently it has been observed that desmoplasia may occur in the absence of malignancy, this was first observed in the normal female breast. And research suggests that the presence of desmoplasia may predispose to the formation of malignancy .
History and etymology
Desmoplasia is a word derived from the Ancient Greek words, "desmos" meaning to restrain and "plasis", meaning formation .