Significance of intra-and extraosseous edema accompanying benign tumors and tumor like diseases

Abstract

Objective To explore the incidence and significance of intra- and extraosseous edema accompanying benign tumors and tumor like diseases. Methods Imaging studies including MR, CT and plain radiograph were retrospectively reviewed in 245 cases of benign osseous tumors and tumor like diseases proved by pathology(borderline tumor, cases associated with pathological fractures, cases with lesions of skull were excluded from the study).The incidence of bone marrow and soft tissue edema were defined on T2WI with fat suppression on MRI in all the cases. χ2 test was performed for the incidence rate of edema in the benign tumors and tumor like diseases. The pre-operative diagnoses were reviewed, and the influence of edema to the differential diagnosis between the benign and malignant was analyzed. Results The total incidence of bone marrow and soft tissue edema associated with benign tumors and tumor like diseases was 37.1% (91/245), which included Langerhans cell histiocytosis 85.2% (23/27), osteoblastoma85.0% (17/20), osteoid osteoma93.6% (29/31),chondroblastoma 87.0% (20/23). There was no statistically significant difference of edema incidence among the above-mentioned four diseases.(χ2=6.35,P> 0.05). Both cases of endosteal capillary hemangioma had edema around. No edema was found around the lesions of other kinds of diseases. 41 of 91 cases (45.1%) with edema were misdiagnosed as malignant tumor by MRI pre-operatively. Conclusion The marrow and soft tissue edema is a common sign in the benign bone tumor and tumor-like diseases, and it is frequently seen in Langerhans cell histiocytosis, osteoblastoma, osteoid osteoma, chondroblastoma. Key words: Bone neoplasms; Magnetic resonance imaging; edema