Extramedullary skeletal muscle metastasis of glioblastoma:A case report and literature review

Objective The aim of the study was to explore the clinicopathologic, immunophenotypic, and diagnostic features of extramedullary metastases of glioblastoma. Methods One case of extramedullary skeletal muscle metastasis of glioblastoma was studied, including the clinical, histological, and immunohistochemical features. Results A 24-year-old man underwent surgical resection for glioblastoma(WHO grade IV) in the left temporal parietal region followed by radiotherapy and temozolomide therapy. One year and nine months later, he developed an extramedullary skeletal muscle metastasis in L4, and the histology was remarkably different from that of the primary glioblastoma specimen. The immunohistochemical analysis also showed changes. In the metastasis, the small cells were negative for GFAP; weakly positive for S-100; and positive for nestin, NSE, and CD56, with 60% of cells positive for p53 and 40% positive for Ki-67. The giant cells showed strong positivity for GFAP and S-100, and weak expression of p53, Ki-67, nestin, NSE, and CD56. The primary glioblastoma specimen showed strong positivity for GFAP and S-100 and was negative for NSE, nestin, and CD56, with around 25% of the tumor cells positive for p53 and a Ki-67 labeling index of 20%. Conclusion Extraneural metastasis(ENM) is a rare complication of glial tumors and glioma stem cells may be related to the metastasis. Since extraneural metastasis may occur in patients without central nervous symptoms, any unusual signs during the follow-up of patients diagnosed with glioblastoma should not be underestimated.

Systematic Analysis of the ArcCheck Diode Arrays for Tomotherapy Delivery Verification

Objective: The aim of this study was to evaluate the functional characteristics of ArcCheck? array detectors and the application for Tomotherapy IMRT plan verification. Method and Materials: The basic character of the ArcCheck applying on Tomotherapy system was tested. The diode testing procedures included the followings: The short term reproducibility, linearity, dose rate dependence, the profile measurement compared to ion chamber. The effect of insert on gamma passing rate was also studied. A total number of 602 Tomotherapy Delivery Quality Assurance (DQA) plans were retrospectively analyzed to obtain the action limit results with statistical significance evaluation. Results: The short term reproducibility, linearity, dose rate dependence, profile to ion chamber correlation and clinical application were all compared with satisfactory outcome with this device. If anterior diode points were properly calibrated with machine absolute output, then there was no significant difference between the ArcCheck phantom with and without insert on gamma passing rate. The average passing rate was 97.5% and the recommend action level was established at 92% based on the 602 patients’ clinical data with 95% confidence level criteria. Conclusion: This comprehensive study shows that ArcCheck is an accurate and efficient device for quality assurance of Tomotherapy with remarkable consistency of 3D volume analysis of arc therapy.