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Dandy-Walker syndrome

Clinical analysis of 23 cases

Raymond Sawaya and Robert L. McLaurin

✓ A clinical analysis of 23 patients with Dandy-Walker malformation indicates that more than 85% of them were diagnosed at or before 1 year of age, and that the incidence of associated anomalies is approximately 50%, with a 17% incidence for agenesis of the corpus callosum. The significance of the presence of these anomalies is substantiated by the fact that of the seven deaths recorded, six were related to this disease and five were affected by associated anomalies. The high mortality rate (26%) is comparable to that of other series. The differential diagnosis with posterior fossa extra-axial cysts is discussed.

Ten patients were primarily treated with excision of the cyst membrane; all of them required subsequent shunting to control the intracranial pressure, demonstrating the futility of this approach. None of the patients treated with lateral ventricle shunting suffered an upward herniation of the posterior fossa contents, suggesting that combined shunting of the lateral and fourth ventricles is rarely necessary. The technical advantages of posterior fossa shunting alone are outlined. Of the 16 survivors, 14 were assessed for their mental development by means of standard psychometric testing. The results of the intelligence quotient (IQ) scoring have indicated that 71% of the patients have subnormal mental development (IQ < 83). There was no significant relationship between retardation and associated anomalies, although agenesis of the corpus callosum was related to poor intellectual development in the two patients so affected (IQ's of 50 and 73).

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Raymond Sawaya and Robert Highsmith

✓ Fresh human brain-tumor samples were assayed for their plasminogen activator (PA) content. Specific molecular weight patterns were identified for each of five common brain tumors and for normal brain, suggesting a cell-specific origin of the various PA forms. Malignant tumors contained higher PA activity and a larger number of molecular weight patterns than benign tumors, with the exception of acoustic neurinomas. Irradiated tumors contained lower PA activity than nonirradiated tumors. Finally, a slight but definite correlation between brain edema and PA activity was detected. The future role of brain-tumor PA's for diagnostic and therapeutic purposes is discussed.

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Raymond Sawaya, Mario Zuccarello and Robert Highsmith

✓ This study was undertaken to confirm the presence of alpha-1-antitrypsin (α 1-AT) in human brain tumors and to attempt to elucidate its significance. Seventy-seven consecutive unselected patients with various brain tumors were entered in this study. The α 1-AT and α 2-macroglobulin contents of the tumor extracts were qualitatively assessed by Ouchterlony immunodiffusion techniques. Plasminogen activator (PA) activity was assayed electrophoretically on sodium dodecyl sulfate gels. The patients were divided into two groups according to the positivity of their tumors to α 1-AT. Sixty-eight percent of the tumors were positive for α 1-AT, and all specimens were negative for α 2-macroglobulin. Clinical and biological parameters obtained in all study patients failed to show statistically significant differences between the two groups with the exception of PA activity (p = 0.001), the peritumoral edema as seen on computerized tomography, and the preoperative serum fibrinogen level. These three parameters were higher in the group with specimens positive to α 1-AT.

This study supports the hypothesis that α 1-AT is produced primarily by tumor cells in proportion to the regional proteolytic and inflammatory activity, and may protect the tumor cells.

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Christopher S. Rumana, Kenneth R. Hess, Wei Ming Shi and Raymond Sawaya

Object. Twenty-two patients who had solitary metastatic brain tumors with dural extension were treated surgically over a 3-year period. Their cases were reviewed to characterize these lesions and to compare the patients with a similar cohort in which there was no dural involvement.

Methods. The median age of the patients was 58 years (range 11–68 years) and the male/female ratio was 12:10. The median preoperative Karnofsky Performance Scale (KPS) score in the group was 90 (range 70–100). The most common histological diagnoses seen in these patients included breast cancer, adenocarcinoma and squamous cell carcinoma of the lung, and renal cell carcinoma. All patients underwent gross-total resection of the tumor and 86% received radiation therapy. The median patient survival time was 11 months, with a median time to recurrent intracranial disease of 19 months. Survival was related to the histological diagnosis. Recurrent disease occurred in 41% of cases. Leptomeningeal disease occurred in three patients (14%). The frequency and time course of development of recurrent disease was not affected by dural resection nor was survival.

These results for patients having metastatic brain tumors with dural extension were compared with those for a cohort of 26 patients in which there were similar histological diagnosis, age, gender, and preoperative KPS score were distributed similarly but in which each patient had a single subcortical metastatic lesion. Those patients had a median survival of 10 months and the median time to recurrence was not reached. Leptomeningeal disease occurred in one patient (4%).

Conclusions. To the authors' knowledge, this is the first reported series of patients with metastatic brain tumors with dural extension. Patients with this disease may be more likely to develop recurrences along the dura and leptomeningeal disease, but the overall survival time in these patients is not different from those patients with intraparenchymal lesions.

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J. Stuart Crutchfield, Raymond Sawaya, Christina A. Meyers and Bartlett D. Moore III

✓ Mutism is defined as a state in which a patient is conscious but unwilling or unable to speak. It has been reported to occur in association with a multitude of conditions, including trauma, epilepsy, tumors, stroke, psychoses, and brain surgery. The cases of two patients who became mute in the immediate postoperative period are presented. The first patient developed mutism following removal of a parasagittal meningioma, and the second following removal of a posterior fossa medulloblastoma. It is believed that transient injury may have occurred to the supplementary motor cortex in the first case and to the dentate nuclei in the second case. It is interesting that these two areas are connected via pathways involving the ventrolateral nucleus of the thalamus, and that lesions of this thalamic nucleus can also lead to mutism. It therefore appears plausible that interruption of these pathways may be involved in the pathogenesis of mutism. Although mutism is an infrequent complication of brain surgery, neurosurgeons should be aware that it may occur following removal of lesions in these areas and that it is generally a transient condition.

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Raymond Sawaya, O. Juhani Rämö, Mei Lin Shi and George Mandybur

✓ Fresh brain-tumor samples were obtained at operation and analyzed for their content of tissue type plasminogen activator (tPA) using an activity assay (gel chromatography zymogram) and an enzyme-linked immunospecific assay. The specimens were taken from 23 glioblastomas, 35 metastatic tumors, 42 meningiomas, 16 low-grade gliomas, and seven acoustic neurinomas; seven specimens were from normal brain.

A strong correlation was found between the results of the two assays (r = 0.77, p < 0.0001). There was a threefold difference in the tPA content of the benign tumors as compared to malignant tumors (p = 0.0006), the latter having less tPA. Histologically benign meningiomas contained higher tPA than malignant meningiomas (p = 0.01); however, the difference between low-grade gliomas and high-grade gliomas was less evident. Overall regression analysis data have shown an inverse relationship between the tissue content in tPA and the presence and degree of tumor necrosis and peritumoral brain edema (p = 0.004 and p = 0.0004, respectively). This finding was most consistent in the glioblastoma group where the correlation coefficient values were r = 0.53 and r = −0.55, respectively. There was no significant correlation between the tissue tPA content and the age and sex, steroid use, or plasma tPA of the patients or the duration of symptoms.

In summary, this is the first demonstration of tPA in a large series of human brain tumors and in normal brain. The differences observed have clear biological significance and, although the source of tPA in tumor tissue is still unknown, a relative reduction in tPA in tumor tissue may play an integral role in the development of tissue necrosis and tissue edema. The lack of tPA in tumor necrosis was not due to tissue destruction and cell death since urokinase was readily detectable in that tissue.