Transarticular invasion of primary bone tumors abutting the sacroiliac joint: an MRI study in 128 patients

Abstract

Background: To investigate magnetic resonance imaging (MRI) manifestation of transarticular invasion of primary bone tumors abutting the sacroiliac joint. Methods: We conducted a retrospective analysis of MRI data in 128 patients from January 2004 to December 2015. The diagnosis confirmed by surgical findings and pathological examination. The tumors of 87 patients located in the ilium and 41 patients in the sacrum. Tumors were divided into high-grade (Group 1), low-grade (Group 2) malignant tumor group and intermediate tumor group (Group 3). Transarticular invasion routes included 3 types: across ligament (Type 1), across articular cartilage (Type 2) and across periarticular tissue (Type 3). Results : Transarticular invasion were observed in 33 patients (25.8%): Group 1 (22 patients) included 15 patients (51.7%) with conventional osteosarcoma and 7 patients (43.8%) with Ewing's sarcoma; Group 2(5 patients) included 4 patients (11.4%) with central chondrosarcoma and 1 patient (7.7%) with chordoma; Group 3(6 patients) included 4 patients (20.0%) with giant cell tumor of bone, 1 patient (16.7%) with chondroblastoma and 1 patient (11.1%) with aneurysmal bone cyst. The difference of transarticular invasion incidence was not significant statistically between primary iliac and sacral tumors ( P > 0.05). The differences were significant statistically between group 2 and group 1, group 3 and group 1, respectively ( P < 0.01). Significant differences were observed among different invasion types ( P < 0.01): type 1(31 times), type 2(15 times) and type 3(5 times). Conclusions: MRI is sensitive and useful to evaluate transarticular invasion of primary bone tumors abutting the sacroiliac joint.