Reticulin fibrosis

A type of fibrosis (Reticulin usually refers to type III collagen) made evident by special reticulin stains. Marrows may show increased reticulin for various reasons including metastatic tumors, lymphoma, and clonal disorders of the marrow (MDS, AML, MPN). Extensive increases in reticulin are characteristic of primary myelofibrosis and a common complication of other MPN.