Fibrous and Fibrohistiocytic Lesions

Abstract

Most tumors of fibrous and fibrohistiocytic origin generally produce collagen but do not form a mineralizing matrix, whereas high-grade tumors may have little to no matrix. Fibro-osseous lesions [fibrous dysplasia (FD) and osteofibrous dysplasia (OFD)] are composed of large volumes of fibrous connective tissue, principally collagens type I and III, as well as osseous areas. Fibrous and fibrohistiocytic lesions span the entire spectrum of clinical behaviors: benign, locally aggressive, and malignant. While with radiologic input, it is usually not difficult to distinguish the benign and malignant ends of the spectrum, some of these lesions have significant overlapping histologic features and necessitate incorporating clinical and demographic information to arrive at the correct diagnosis.