Abstract
OBJECTIVE: To explore the imaging features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumours (pPNETs). METHODS: The imaging features and pathological characteristics of eight cases of surgically and pathologically confirmed Ewing sarcoma/pPNET were analysed retrospectively in light of recent literature on the disease. RESULTS: The peak age was between 10 and 20 years. The lesions tended to be spindle shaped and dural based, usually widely so. CT showed that the lesions had slightly uneven high density in five cases and iso-low mixed density in three cases; marked heterogeneous enhancement was seen in all cases after contrast injection. MRI of the lesions showed varying proportions of isointense and hypointense signal in all cases on unenhanced T1 weighted imaging and varying proportions of isointense and hyperintense signal on T2 weighted imaging. After contrast injection, marked heterogeneous enhancement was seen in all cases; three cases showed a short and nodular dural tail and five cases showed adjacent skull erosion and osteolysis. Pathological results included high cell density, haemorrhage and necrosis. The cells resembled lymphocytes and spindle cells with transparent cytoplasm. CD99 and vimentin were expressed by all tumour cells. CONCLUSION: Features of meningeal Ewing sarcoma/pPNETs include peak incidence at 10-20 years of age, a broad connection to the meninges, a thick dural tail involved with tumour, skull and scalp erosion and early metastasis. Necrosis and cystic changes are the common histological findings. ADVANCES IN KNOWLEDGE: The imaging features of meningeal Ewing sarcoma/pPNETs have not been reported. The study helps to identify meningeal Ewing sarcoma/pPNETs and meningioma.