The Clinical Analysis Of Intracranial Primitive Neuroectodermal Tumors (25 Cases)

Objective: To investigate the effect of image presentation, pathological examinations and histopathological examinations in the diagnosis course and the influence of microsurgical therapy and whole brain external radiation therapy on the prognosis of intracranial primitive neuroectodermal tumors.Method: A retrospective review of 25 patients suffering from intracranial primitive neuroectodermal tumors diagnosed by virtue of pathological and immunohistochemical methods was performed between June 1998 and June 2006, and all patients were followed up.There were 12 male patients and 13 female patients ranging between 3to 52 years old, with a median age of 27.5 years old. There were 9 supratentorial tumors, 9 infratentorial tumors (7cases in cerebellum, 2 cases in cerebellum and the fourth ventricle), 1case in the fourth ventricle, 1 case in the third ventricle, 1 case in the lateral ventricle, 1 tumor in cerebellopontine angle area, 1 case in thalamus, 1 case in subdural cavity, 1 case in clival region.16 cases underwent routine operation, the rest 8 cases underwent microneurosurgery, 1 case underwent ventriculoperitoneal shunt. And 11 cases underwent postoperative radiotherapy. The specimen were fixed by formaldehyde, embedded by paraffin, sliced into 4μm thick pieces, stained with hematoxylin-eosin (HE), and observed under light microscope. The specimen also underwent immunohistochemical test for neuroendocrine markers. After departure from the hospital, 11 underwent whole brain external radiotherapy. The total radiation dose ranges from 50Gy~60Gy and the treatment course was divided into 25-30 segments, which lasted for 5-6 weeks. Identified postoperative recurrence depended upon the identified space-occupying lesions shown in cerebral and spinal imaging. The follow-up time varied among different cases from 13 days to 33months. The postoperative living period is the summation of total postoperative living months. All data were processed by virtue of the statistical method: recurrence rate and survival rate were analyzed by chi-square test, postoperative living period was analyzed by independent t-test.Results:1. All cases were presented with symptoms concerning with high intracranial pressure together with lesion-related position-located cerebral dysfunction; their MRI results coincide with typical PNET image shown in MRI:most lesions were presented to be circular or quasi-circular in shape, irregular ones were also witnessed however rare in number;most lesions were well defined and homogenous T1WI hypointense and T2 hyperintense areas comparatively;cerebrospinal fluid-like signals were shown in some cases while most lesions were presented homogeneous enhancement.2. Homer-Wright(H-E) chrysanthemum was witnessed in 20 cases and more than two kinds of neuroendocrine markers were detected in all cases, thus all could be diagnosed as PNET definitely according to the generally-acknowledged Schimidt standard. On the other hand, the crossover presentation rate of neuronal differentiation markers(Syn: 64.0%;NSE:44.0%;NF:4%) and the glial differentiation related marker(GFAP:4%) is low. Meanwhile, the crossover presentation rate of well-differentiation related marker (NSE) and poor-differentiation related marker (Vim) is also not remarkable.3. All cases were followed up. 21 cases were dead, the rest 4 were alive. The general postoperative living period of those who underwent postoperative radiotherapy was confirmed to be significantly longer than controlled group.Conclusions:1. Owing to its special character of enormous malignancy, early diagnosis and effective treatment are of pivotal importance for the prognosis of patients suffering from intracranial primitive neuroectodermal tumors. MRI, pathological as well as immunohistochemical examinations contribute a lot to early and accurate diagnosis of intracranial PNETs. Differentiation related makers could serve as indicators in identifying tumor differentiation levels while the definition of tumors'two-way differentiation potential relies on systemic analysis of massive cases.2. Postoperative whole brain external radiotherapy prolongs the postoperative living period significantly. Further progress in improving prognosis depends on the perfection of comprehensive therapy. We strongly suggest the application of postoperative whole brain and spine external radiotherapy to prevent the potential metastasis through subdural cavity.