Abstract: Objective To analyze the clinical features,neuroimaging presentations,treatment and prognosis of skull mass-like plasma cell myeloma.Methods The clinical data of 5 patients with skull mass-like plasma cell myeloma,which were confirmed by histological examination and immunohistochemistry,were retrospectively analyzed.Preoperative radiographies included CT and /or MRI in all patients were obtained;all patients underwent direct surgery,and 4 patients received a course of postoperative radiotherapy,and /or chemotherapy.All patients were followed up from 6 to 120 months.Results The age of patients with skull mass-like plasma cell myeloma ranged from 36 to 66 years with an average of 51.8 years.The incidence was about 0.03% of intracranial tumors in our hospitalfor the same period.The initial characteristic symptoms and signs of these patients included skull mass,headache and cranial nerve palsy.CT features showed an expansile,lytic lesion involving the diploic space and the inner and outer tables of the skull,typically compressing adjacent brain;diffuse homogeneous enhancement after contrast material administration was generally seen,erosion of the full thickness of the skull was different from meningioma.MRI was extra axial and nearly isointense with gray matter on T2-weighted MR images,and diffusely enhanced after administration of contrast material.The tumors of 4 patients were totally removed,1 skull base tumor was partially removed.During operations the tumor often showed hypervascular presentation involving the skull.There were no operative mortality and serious complications in this series.During the follow-up,2 patient were dead,survival time was 120 and 2 months separately,3 were still alive,follow-up time was 118,12 and 6 months.Conclusion The imaging of skull mass-like plasma cell myeloma bore some similarities to meningioma.Erosion of the full thickness of the skull has differential value.Finding of systemic multiple lesions is essential for treatment and evaluation of prognosis.Controlling the bleeding during the operation is important.Post-operative radiotherapy and chemotherapy following can improve the patient's prognosis.

Key words: skull plasma cell myeloma, surgery, radiotherapy, chemotherapy