Value of Diffusion-weighted Imaging and Apparent Diffusion Coefficient in the Differential Diagnosis of Posterior Fossa Solid Hemangioblastoma / 中国医学科学院学报

To investigate the value of diffusion-weighted imaging(DWI)and apparent diffusion coefficient(ADC)in the diagnosis and differential diagnosis of posterior fossa solid hemangioblastoma(PFSH). We retrospectively analyzed the clinical data of 15 PFSH patients and 58 patients with other hypervascular tumors in the posterior fossa(the latter included 23 cases of meningioma,5 cases of medulloblastoma,8 cases of acoustic neuroma,4 cases of hemangiopericytoma,5 cases of lymphoma,9 cases of metastatic tumor,3 cases of astrocytoma,and 1 case of choroid plexus papilloma)confirmed by operation and pathology.All patients underwent axial DWI scans,and the mean ADC value of solid part of the tumors and the adjacent normal cerebellar white matter were measured,and then the normalized ADC was calculated.In addition, test was used to compare the differences in mean ADC and normalized ADC between these two groups,and receiver operating characteristic(ROC)curve was applied to analyze the diagnostic performance of normalized ADC. Of all the 15 PFSH patients,DWI appeared hypointense in 12 patients and isointense in 3 patients;the signals on ADC maps were isointense or hyperintense;the mean ADC value of PFSHs was(1.881±0.445)×10 mm /s and the normalized ADC was 2.70±0.62.In contrast,in 58 patients with other tumors in the posterior fossa,DWI appeared hyperintense in 51 cases,isointense in 3 cases,and hypointense in 4 cases;the mean ADC value was(0.771±0.202)×10 mm /s,and the normalized ADC was 1.17±0.33.Thus,the ADC value and normalized ADC value were significantly higher in PFSH than in other tumors in the posterior fossa(=9.419,<0.001;=9.184,<0.001).The cut-off value of the normalized ADC for the diagnosis of solid hemangioblastoma was 1.89,with the sensitivity and specificity being 100%and 96.6%respectively,and the area under the ROC curve was 0.989. ADC and normalized ADC are valuable in the differential diagnosis of PFSH from other tumors with abundant blood supply.

Surgery of a Solid Hemangioblastoma at the Cervicomedullary Junction

The surgical removal of solid deepseated hemangioblastomas remains challenging, because treatment of these lesions is often complicated by severe bleeding associated with the rich vascularity of this tumor, and by severe neural tissue injury associated with the difficulty of en bloc resection, especially when the tumor is located at the cervicomedullary junction. Therefore, preoperative embolization of deepseated solid hemangioblastomas may play an important role in successful surgical removal by reducing major bleeding and neural tissue damage. A 24-year-old woman, 28-weeks pregnant, was admitted to our hospital for the evaluation of quadriparesis, and brain magnetic resonance imaging(MRI) revealed intra-axial mass lesion in the cervicomedullary junction. After delivery, her neurologic symptoms became aggravated, and we decided to operate. Preoperative angiography revealed a hypervascular tumor in the posterior fossa, and embolization of the main feeding artery using gelfoam and microcoil, resulted in marked reduction of tumor vascularity. She underwent a midline suboccipital craniotomy involving the removal of the arch of C-1. The tumor was totally removed through a midline myelotomy, and at her 6-month follow-up she walked independently. We report on the combined use of the preoperative embolization of feeding vessels and subsequent operative resection in a patient with a solid hemangioblastoma at the cervicomedullary junction immediately after delivery.