Dumbbell Scoring System

DSS was based on four characteristic imaging features confirmed Study Design. Retrospective diagnostic analysis. Objective. The aim of the study was to establish a new scoring system, the dumbbell scoring system (DSS), for preoperative evaluation of the malignant potential of spinal dumbbell tumors (SDTs). Summary of Background Data. Among SDTs, benign tumors such as schwannomas occur frequently, whereas malignant SDTs, including malignant peripheral nerve sheath tumors, are uncommon. No scoring system has been developed to preoperatively diagnose the malignant potential of SDTs. Methods. We retrospectively reviewed the records of 59 consecutive patients with SDTs. The following imaging features were recorded: tumor size, tumor shape, tumor boundary, pattern of enhancement of intratumoral lesions (homogeneous or heterogeneous), cyst formation in the tumors on magnetic resonance imaging, and enlargement of neural foramina and scalloping or osteolytic destruction of surrounding bones on computed tomography. The prevalence of characteristic imaging features in malignant and benign SDTs were evaluated, and appropriate cut-off points for the DSS score were obtained using receiver operating characteristics. Results. Twenty cases were confirmed to be malignant tumors. Pathological diagnoses of the malignant SDTs were as follows: 11 cases of malignant peripheral nerve sheath tumor; 3 cases of malignant lymphoma; and 1 case each of extraskeletal Ewing sarcoma, hemangiopericytoma, hemangioendothelioma, malignant myoepithelioma, neuroblastoma, and plasmacytoma. The