Vascular tumors of bone: imaging findings

Purpose: To identify radiological features of malignant vascular tumors of bone, which can be used to avoid erroneously diagnosing metastases based on radiological multifocality, and histological epitheloid phenotype.

Materials and methods: From the databases of the Bologna & Netherlands Committee on Bone Tumors, 63 patients with a histological diagnosis of malignant vascular tumor of bone were retrieved. Epidemiological and imaging characteristics were recorded on a case record form.

Results: In 63 patients, 185 lesions were detected by radiographs (61 patients) and/or CT (30 patients) and/or MRI (19 patients). Multifocality was observed in 25 patients (40%), in these patients most lesions were located in the femur. Typically lesions were well-defined, osteolytic, had a geographically pattern of destruction and were also located in the femur. Most lesions showed cortical destruction (118 lesions). No periosteal reaction was seen in most cases (121 lesions). In 13 of 39 patients (33%) tumor extension was more advanced and/or (additional) lesions (29 lesions; 17%) were visible on MRI and CT. In 20 cases (51%) cortex destruction was better shown on CT or MRI. In six patients (15%) periosteal reaction was only seen on MRI or CT and not on radiographs. In 16 (41%) cases soft tissue extension was only seen on MRI or CT, and not on radiographs. Extensive reactive changes on T2-weighted images were seen in 11 patients (58%).

Conclusion: When single, or regional multifocal osteolytic, well-marginated lesions with cortical destruction are seen, in the femur, and with marked reactive soft tissue changes on MRI, a diagnosis of malignant vascular tumor should trigger the use of additional immunohistochemistry to confirm the vascular nature of the tumor. CLINICAL RELEVANCE STATEMENT: Because of epithelioid phenotype at histology, radiological signs are key in entertaining a diagnosis of malignant vascular tumor of bone which should trigger the use of appropriate immunohistochemical stainings.