CT
What thickness of cartilaginous cap is suspicious for malignant degeneration in osteochondromas?
1.5 cm in skeletally mature patients
What percentage of patients with HME will have malignant transformation of an osteochondroma?
3%–5% of patients with HME, 1% of solitary osteochondromas
The mass lesion is again identified within the pelvis, and appears to originate from an osteochondroma at the posterior aspect of the right superior pubic ramus. The mass lesion measures 15 x 9.4 x 14 cm in AP, transverse, and superoinferior dimensions, respectively. The mass demonstrates a rings-and-arc pattern of calcification, suggesting a chondroid matrix.
The mass displaces the urinary bladder, which is decompressed with an indwelling Foley catheter. The mass also has a mass effect on the rectum, displacing it posteriorly and to the left.
The mass lesion does not demonstrate any vessel or neurovascular bundle encasement. No additional mass lesions are identified.