Fibrogenic and Fibrohistiocytic Tumors

Abstract

• Lesions of fibrous origin include those tumors of fibrogenic and fibrohistiocytic origin. • Tumors of fibrogenic origin are those that produce collagen and demonstrate absence of bone and cartilage formation • Desmoplastic fibroma and fibrosarcoma make up the fibrogenic tumor category. • Desmoplastic fibroma is a rare benign tumor often associated with recurrence. • Desmoplastic fibroma is also one of those rare lytic bone tumors that demonstrate predominantly low signal intensity on T2-weighted MR images, reflecting its collagenous nature. • Microscopically, differentiation may be difficult between desmoplastic fibroma and a low-grade fibrosarcoma, with the absence of herringbone pattern and pleomorphism being the distinguishing factor. • Tumors of fibrohistiocytic origin encompass both benign and malignant fibrous histiocytoma. • Fibrohistiocytic tumors are surrounded in controversy, which is further underscored by the fact that the rare entity of benign fibrous histiocytoma is histologically identical to nonossifying fibroma (NOF), with clinical and radiographic features and location being the distinguishing factors between the two. • Fibrosarcoma and malignant fibrous histiocytoma (MFH) are rare primary bone tumors with overlapping histologic and radiographic appearance. • Only a close histological examination may differentiate fibrosarcoma and malignant fibrous histiocytoma.