Cystic changes in desmoplastic fibroma of bone: A new MRI finding

Aim: To evaluate the magnetic resonance imaging features of desmoplastic fibroma (DF) of bone. Materials and methods: Two radiologists retrospectively evaluated imaging findings of pathologically confirmed DFs in eight patients. Involved sites and longitudinal location in long bones were evaluated using radiography and computed tomography (CT). At MRI, the presence of low signal areas on T2-weighted images (low-T2), enhancement, cystic changes, and locations of the mass were evaluated. The location of masses was evaluated, based on cortical disruption and adjacent soft-tissue extension. Results: Involved sites were the femur in three patients, the tibia in two, and the humerus, fibula, and pubic bone in one each. Of the seven masses in the long bones, three were located in the epi- and metaphysis, two in the meta- and diaphysis, one in the diaphysis, and one in the epiphysis. Seven masses had areas of low T2-weighted or heterogeneous enhancement, and three (38%) showed cystic changes. cortical disruption was seen at MRI in six of eight patients (88%). Conclusion: DFs contained cystic change. Cortical disruption may also occur, which may cause confusion with malignant lesions.