Figure 13c. Craniofacial conventional chondrosarcoma in a 26-year-old man with nasal symptoms. (a) Coronal CT reformatted image reveals a low-attenuation mass (M) replacing nasal bones and displacing the nasal septum with small subtle chondroid matrix mineralization (arrows). (b, c) Sagittal T1-weighted (570/15) MR image obtained without (b) and coronal T1-weighted MR image (570/15) obtained with (c) gadolinium show the low-signal-intensity mass (M) with mild peripheral and septal enhancement (arrows) replacing the area of the cribriform plate in the anterior cranial skull base and extending into the nasal region. Severe sinus disease is seen. (d) Axial T2-weighted fat saturation (2,200/80) MR image shows that the mass (M) erodes the medial wall of the right maxillary sinus and left maxillary sinus with marked high signal intensity similar to that of mucosal thickening and fluid in both sinuses. Matrix mineralization cannot be seen. (e) Photograph of the gross specimen show portions of the cribriform plate superiorly, maxillary sinus, and lobules of cartilage growth (*).