Epithelioid osteoblastoma and osteoblastoma-like osteosarcoma:a clinicopathological analysis

WU Juan; ZENG Ju; PAN Mei; XU Gang

doi:10.3969/j.issn.1007-8096.2026.01.019

Abstract：Objective To explore the clinical characteristics,imaging manifestations,pathological diagnosis,and differential diagnosis of epithelioid osteoblastoma(EOB)and osteoblastoma-like osteosarcoma(OBOS).Methods Twenty-two cases of EOB and eleven cases of OBOS were collected,and a comparative analysis was conducted on their clinical imaging data,pathomorphological features,immunophenotypes and molecular genetic alterations,along with a review of the domestic and international literature.Results The male-to-female ratio in EOB was 2.1∶1,with ages ranging from 9 to 63 years(average 24.2 years).Among them,12 cases involved axial bones,6 cases involved long shafts at the metaphysis,and 1 case involved the pelvis,talus,scapula and clavicle each.Clinically,most patients experienced pain after activity,with imaging showing expansile lytic bone destruction.Histologically,the lesions exhibited epithelioid cells and osteoid tissues,with abundant blood sinuses between cells,but no definitive pathological mitotic figures were observed.The male-to-female ratio in OBOS was 0.57∶1,with ages ranging from 4 to 48 years(average 26.8 years).Among them,7 cases involved long bones,2 cases involved the jawbone,and 1 case involved the ribs and ischium each.Clinically,patients experienced persistent pain that could not be relieved,accompanied by local masses.Imaging showed unclear lytic or mixed osteosclerotic bone destruction with periosteal reaction.Histologically,the lesions exhibited osteoblastomatous hyperplasia with moderate atypia and atypical mitotic figures,showing invasion into bone and soft tissues.Conclusion The treatment and prognosis of EOB and OBOS differ,and the differential diagnosis requires a comprehensive analysis of clinical,imaging and histopathological morphology.