The neurosurgical management of optic glioma ROBERT T. TENNY, M.D., EDWARD R. LAWS, JR., M.D., BRIAN R. YOUNGE, M.D., AND JAMES A. RUSH, M.D.

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1 J Neurosurg 57:52--58, 1982 The neurosurgical management of optic glioma Results in 10 patients ROBERT T. TENNY, M.D., EDWARD R. LAWS, JR., M.D., BRIAN R. YOUNGE, M.D., AND JAMES A. RUSH, M.D. Departments of Neurologic Surgery and Ophthalmology, Mayo Clinic, Mayo Medical School. Rochester, Minnesota ~/ A series of 10 patients with surgically verified optic nerve gliomas is presented. Anterior lesions primarily affecting the optic nerve were present in 2 patients, who have a long-term survival rate of 85.5%. Posterior lesions primarily affecting the optic chiasm were present in 62 patients, most of whom underwent radiation therapy postoperatively, and they have a long-term survival rate of 50%. Unequivocal signs of neurofibromatosis were present in 1%. On the basis of these findings and a review of the literature, recommendations are made for the surgical management of these tumors. KEY WORDS 9 optic nerve glioma astrocytoma proptosis 9 radiation therapy neurofibromatosis D ESPITE the straightforward approach to the treatment of primary tumors of the optic nerve presented by Wishart 6~ in 1833, the problem of the management of these lesions has become more complex as medicine has advanced. The differentiation of the various types of orbital tumors was first accomplished by Byers in An early study of the pathology of optic gliomas was carried out by Parsons, ~ and reported in The surgical accessibility of these lesions was initially described by Martin and Cushing? ~ A surgical series in the presteroid era was reported by Jefferson, 22 and a larger series that straddled the pre- and poststeroid era was reported by Dodge, et al.13 A number of reports of patients with optic gliomas treated by surgery and/or radiation therapy have been presented since. 2,3,6-a,1z, 1-16,19,26-31,33,38,1--6,8,51-55,63 There has been considerable controversy about the etiology of the disease, its natural history, and the roles of surgery, radiation therapy, and simple observation in the management of patients with optic nerve gliomas. Optic nerve gliomas occur infrequently, representing about 0.6% to 1.2% of primary intracranial tumorsy Lesions confined to the optic nerve occur most frequently in prepubertal children, while chiasmal lesions are more commonly seen in adolescents. 5~,6~ Lesions affecting the optic nerve tend to have a female 52 preponderance, and chiasmal lesions have an equal sex distribution. The distribution of optic nerve lesions is such that 26% to 36% of the tumors involve the prechiasmatic part of the optic system and 6% to 73% of the lesions involve the optic chiasm, optic tracts, and/or anterior third ventricle, and are generally considered surgically unresectable. In 1% to 36% of patients with optic nerve glioma, there is evidence of central nervous system (CNS) neurofibromatosis. 1~176 Patients with neurofibromatosis have an increased incidence of bilateral optic nerve lesions. Diagnosis Optic Gliomas In tumors that are confined to the anterior visual (prechiasmatic) pathway, the presenting symptoms (proptosis and visual loss) usually develop over a 6- to 9-month course, s'2,25'35'59'6~ Funduscopic examination usually shows optic disc edema. In patients with chiasmal lesions, the duration of the symptoms averages about 1 year, and the chief complaint is usually decreasing vision. Optic disc pallor is frequently present on funduscopic examination? 3,6 There are cases of optic nerve and chiasmal gliomas that present with papilledema and normal visual acuity, but these are exceptional. J. Neurosurg. / Volume 57/October, 1982

2 Management of optic gliomas In 12% to 20% of patients with optic gliomas, there is an associated endocrinopathy, v,'~ most commonly seen in patients with chiasmal lesions that extend into the hypothalamus. These patients frequently have symptoms and signs of increased intracranial pressure (ICP). It was originally thought that adequate information for diagnosis could be obtained from skull x-ray films, and it has been shown that in approximately 90% of standard roentgenograms skull markings suggestive of increased ICP, enlarged optic canals, or an abnormal sella (J-shaped or pear-shaped sella) were demonstrated. 17,18 Enlargement of the optic canals is commonly due to meningeal hyperplasia in the region of the optic foramen. The advent of the computerized tomography (CT) scanner has radically changed the accuracy of radiological diagnosis of optic nerve gliomas. ',5,17 On a CT scan through the orbits, optic nerve gliomas can appear as uniform thickening of the entire nerve, a solitary fusiform enlargement of the nerve, or as irregular solid thickening along the nerve. In a series of 10 patients carefully studied by CT scan, 5 three had bilateral lesions that were not clinically suspected. Etiology and Pathophysiology In 1912, Hudson 2' and, in 1922, Verhoeff 56 proposed that optic nerve gliomas were of congenital origin. It is believed that the tumor arises from supporting astrocytes in the nerve sheaths and that axonal attrition occurs as it enlarges. The histopathology of this lesion is such that the tumor may either be sharply demarcated from normal optic nerve or it may infiltrate the optic nerve. H As the tumor cells spread and compress the fibers of the optic nerve, the nerve will become demyelinated and optic atrophy results. 23 Hyperplasia of meningeal tissue frequently occurs, but is not peculiar to tumors of the optic nerve and has been observed elsewhere in the CNS surrounding indolent glial hamartomas. ~ A frequent finding in optic nerve gliomas is the presence of microcysts that are extracellular accumulations of a substance, positive to periodic acid-schiff (PAS) and acid mucopolysaccharide, that is produced by the astrocytes. It is thought that this mucoid hydrophilic material may be in part responsible for the progressive enlargement of the tumor, and it may contribute to axonal degeneration. 9,6 Hoyt and Baghdassarian 26 stated that arachnoidal proliferation and mucoid formation are self-limiting processes, and that most optic gliomas are clinically indolent tumors that tend to enlarge and cause symptoms early in life, then remain static thereafter. Malignant degeneration of these tumors has been documented, but is rare. From the standpoint of both pathology and therapy, these lesions can be divided into two groups. The anterior group is composed of orbital, intracanalicular, and intracranial prechiasmatic lesions in which the tumor is confined to the optic nerve (not invading Number of patients 16 N = 2 1 [~.~\\~l ~ Females 12 k\\\\\n21~ 7// Males W//////K,.\...\\,~r//////A ~,\\\\\',~\\'%\' t,.\\\\\',l ~/r Age at surgery, years FIG. 1. Age distribution in patients with anterior unilateral optic gliomas. Number of patients N=62 Females Males ~//X////J/////~'///~////IY////X///IA///I/Z~///N////X////N///~\\\~\\\~ , Age at Surgery, years FIG. 2. Age distribution in patients with posterior bilateral optic gliomas. the dura). The posterior group comprises tumors of the optic chiasm, hypothalamus, and anterior third ventricle. Many of these lesions are typical "juvenile" pilocytic astrocytomas. In some cases, there is evidence of chiasmal invasion from a more posterior hypothalamic focus. Radiation Therapy There are now numerous reports documenting favorable responses of incompletely resected posterior lesions to radiation therapy, with improvement occurring both in patients' survival and in their visual status. 6'1z'1'16'25'30'31'3'37'39'51'52'62 The efficacy of radiation therapy in unilateral anterior lesions is less clear. Summary of Cases The Mayo Clinic series consists of 10 patients with optic nerve or chiasmal gliomas diagnosed between 1915 and Anterior tumors confined to one optic nerve were present in 2 patients (Fig. 1). The age range of this group was 15 months to 7 years, with a mean age of 12 years. There were 27 females and 15 males. Posteriorly located tumors involving the chiasm, optic tracts, or both optic nerves intracranially were present in 62 patients (Fig. 2). The age range of this group was I l months to 6 years, with a mean age of J. Neurosurg. / Volume 57 / October,

3 R. T. Tenny, E. R. Laws, Jr., B. R. Younge and J. A. Rush TABLE 1 Distribution according to anatomical site in 10 cases of optic glioma Anatomical Site Male Female Total anterior unilateral lesions orbital orbital & intracranial total cases 2 posterior lesions primarily chiasmal chiasm & one optic nerve chiasm & both optic nerves chiasm & third ventricle total cases years. There were 37 females and 25 males. The distribution of the tumors by anatomical site is given in Table 1. Associated clinical findings are described in Table 2. Definite signs of neurofibromatosis were present in three patients with unilateral lesions and in 11 with bilateral lesions. The plain radiographic findings were as anticipated and are given in Table 3. The "fourth-generation" CT scanner has contributed greatly to the preoperative diagnosis (Fig. 3). The basis of the diagnosis and the histopathology are outlined in Table. In a retrospective surgical series such as this, survival is the most practical and definitive end-point for analysis. Follow-up statistics in this series were complete except for two patients with anterior lesions and one with a posterior lesion. The mean follow-up period was 13 years. The results of therapy with regard to survival status for anterior and posterior lesions are presented in Tables 5 and 6. Proptosis was satisfactorily corrected in all of the patients with anterior lesions. Further results with regard to vision will be reported in detail in a later communication. A systematic attempt to analyze the overall quality of survival was not practical. Operative mortality (within 30 days of surgery) was.8% overall. FIG. 3. Computerized tomography scans. A: Right intraorbital optic nerve glioma. B: Unilateral multilobulated intraorbital right optic glioma. (Reproduced from Forbes GS: Computed tomography of the orbit. Radiol Clin North Am 20:37-9, 1982, with permission.) C: Optic glioma with severe proptosis. (Reproduced from Forbes GS, Sheedy PF, Waller RR: Orbital tumors evaluated by computed tomography. Radiology 136: , 1980, with permission.) D: Posterior optic glioma involving the chiasm. 5 J. Neurosurg. / Volume 57/October, 1982

4 Management of optic gliomas Discussion In 1958, Dodge, et al., ~3 reported a series of 6 cases evaluated at the Mayo Clinic between 1915 and Anterior tumors involving the optic nerve were seen in 12 children, all of whom had proptosis. The age range was 2 to 12 years, with a mean age of 8.8 years; 10 were females. Posterior lesions involving the chiasm or optic tracts were present in 3 patients. Bilateral visual loss was found in 23 of these cases and nine had a "typical bitemporal defect." Nine of these patients had endocrine disturbances. The average age of this group was 1 years, and there was a slight male preponderance (19 of 3 patients). The results following surgery were generally satisfactory, and the influence of radiation therapy was not systematically analyzed. These cases, with an additional follow-up period, are included in this series. In 196, Chutorian, et al, 6 reviewed 56 cases in children seen at the New York Neurological Institute. There were 0 cases with biopsy-proven tumors. The optic nerve alone was involved in 26 patients, none of whom died as a result of the tumor. There were 30 children with chiasmal tumors, the majority of whom were treated with irradiation. At the time of the review, 19 of the patients with chiasmal tumors were alive and 11 were dead. The authors concluded: "The documented failure of pneumoencephalography and lateral orbitotomy to detect and prevent intracranial extension... constitutes evidence in support of the transcranial approach whenever surgery is indicated." Matson, 3 in 1969, reported 23 cases from Boston Children's Hospital. The patients ranged in age from 6 months to 12 years, and sex incidence was equal. The optic nerve alone was involved in five, the chiasm in 15, and both nerve and chiasm in three. All of the patients with optic nerve lesions had exophthalmos. Careful local radiation therapy was generally recommended for the chiasmal lesions. MacCarty, et al., 3~ reported a series of 20 cases in Anterior lesions involving the optic nerve only were present in five cases, and posterior lesions involving the chiasm in 15 cases. Radiation therapy was given to 16 of the 20 patients, and was generally believed to be beneficial. Surgical therapy was considered "successful" in about 25% of the cases. These cases are also included, with an additional follow-up period in this series. Wong and Lubow 62 collected 2 cases from the Children's Hospital of Columbus, Ohio, the University of Iowa Hospitals, and Ohio State University Hospitals; these cases were all treated between 199 and Histological records were available in 28 patients. Eight patients received no treatment (six had exploratory craniotomy); one of these, who had an extensive tumor and hydrocephalus, died, but in the others the disease had not progressed. Tumors confined to one optic nerve were removed in 10 children, and all had remained well. Partial surgical excision was accomplished in 15 patients; all but one, who died TABLE 2 Associated clinical findings in 10 patients with optic glioma Associated Findings % Cases neurofibromatosis 1 endocrine disorders 12 hydrocephalus 9 cranial nerve palsy (other than 2nd nerve) 8 TABLE 3 Positive findings on plain skull films in 10 cases of optic glioma X-Ray Findings % Cases enlarged optic canal abnormal sella intracranial pressure 11 other 9 TABLE Pathological analysis in 10 cases of optic glioma Pathology No. of Cases astrocytoma, Grade I 28 astrocytoma, Grade II astrocytoma, Grade III 19 ungraded glioma 32 inadequate specimen 1 not biopsied 20 TABLE 5 Results of therapy in 2 patients with anterior unilateral optie nerve gliomas No. of Cases Therapy Alive Dead Lost to Follow-Up none (exploration only) 3 0 surgery only "total" excision subtotal removal 1 2 surgery & radiation therapy "total" removal & irradiation subtotal removal & irradiation 1 2 exploration & irradiation total cases * 2 percent of cases 85.7 * One postoperative death and three deaths from late recurrence of tumor, including one biopsied tumor which underwent malignant degeneration to neurofibrosarcoma. TABLE 6 Results of therapy in 62 patients with posterior optic gliomas Therapy No. of Cases Alive Dead none (exploration only) 0 2 biopsy only 3 9 exploration & irradiation 8 3 biopsy & irradiation exploration & chemotherapy 0 1 total cases percent of cases * * Four postoperative deaths (within 30 days of surgery). Lost to Follow-Up J. Neurosurg. / Volume 57/October,

5 R. T. Tenny, E. R. Laws, Jr., B. R. Younge and J. A. Rush of hydrocephalus and pneumonia, had remained well from 1 to 20 years. Radiation therapy was given to nine patients, and none showed progression of their disease. Wong and Lubow favored a conservative approach, including biopsy, when this is technically safe to accomplish, and subsequent observation. In 1973, Lloyd z5 presented an extensive review of 1 patients from the Hospital for Sick Children in Toronto. In nine patients with unilateral optic nerve tumors treated surgically the results were excellent, and all were living and well without recurrence at the time of follow-up review. There were 12 children with bilateral or chiasmal tumors who remained well during the follow-up period, and 20 in whom the disease progressed. The author concludes as follows: "If neurological signs of extensive cranial involvement are present, including hemiplegia and hydrocephalus, no treatment other than shunting procedures and radiation is indicated. But, if the diagnostic signs suggest the tumor is still unilateral, within the orbital or intracranial portion of the nerve, then surgical intervention is indicated. In these patients total excision of the tumor is possible and should be undertaken." Miller, et al., 37 in 197, reported a series of 51 cases from the Johns Hopkins Hospital, treated from 1930 to There were 11 patients (nine children) with biopsy-proven anterior optic nerve gliomas, and six of these were females. All of these patients had proptosis. Biopsy-proven posterior chiasmal gliomas were present in 29 cases (2 children), and those treated with postoperative radiation therapy fared better than those who were not irradiated, particularly when the tumor extended beyond the chiasm. After careful analysis, the authors concluded as follows: "We think it unwise to diagnose an optic glioma on the basis of neuroradiological techniques and clinical judgment alone... Patients with evidence of involvement beyond the chiasm -- so-called 'posterior tumours' -- should receive at least one course of radiotherapy, while those with intrinsic chiasmal lesions need not be irradiated. We do not recommend attempts at either total or subtotal resection of these tumors. The diagnosis of gliomas confined to the optic nerve should also be established unequivocally by biopsy." In another pediatric series, Oxenhandler and Sayers 39 in 1978 reported 28 cases from the Columbus Children's Hospital. Neurofibromatosis was present in 36% of these patients. There were 12 males and 16 females. Unilateral anterior optic nerve involvement occurred in 10 of these children, and chiasmal involvement was found in the remainder. The authors commented as follows: "We favor surgical resection of the unilateral optic nerve glioma in the young patient in whom follow-up examination is unreliable, unilateral visual loss profound, or proptosis excessive... If... there is any question as to the origin of an anterior hypothalamic tumor, exploration should be undertaken to rule out the possibility of a tumor other than an optic glioma..." They recommended radiation therapy in patients with hypothalamic involvement and in cases of chiasmal glioma with progressive visual loss. DeSousa and associates 12 reported 29 children from the Indiana University Medical Center in Only three of these patients had optic nerve involvement alone. Of the 26 patients with chiasmal involvement (average age less than 2.3 years), 12 had evidence of the diencephalic syndrome. Postoperative radiotherapy resulted in reversal of the diencephalic syndrome in the 10 patients so treated. It was claimed that chemotherapy with BCNU (l,3-bis(2-chloroethyl)-lnitrosourea) was effective in the two patients treated with this agent. These authors were relatively conservative in their recommendations for postoperative radiotherapy, as the study group contained a high proportion of very young children. Visot, et al, 57 reported 0 cases from the HSpital Foch in France, of whom 25 were treated surgically, and 38 had radiation therapy. All four of their patients with unilateral intraorbital gliomas were living and well, 1 of 17 patients with tumors confined to the chiasm were well, and 11 of 19 patients with "invasive" chiasmal tumors were well. It is of considerable interest that they noted CT evidence of a decrease in size of seven of these large tumors after radiation therapy. Dosoretz and associates TM reviewed 20 patients with biopsy-proven optic gliomas treated at the Massachusetts General Hospital. They concluded that surgery alone was adequate therapy for patients with disease limited to one optic nerve, and they recommended biopsy and radiation therapy for more extensive neoplasms. An unbiased review of the results of therapy for optic nerve gliomas is virtually impossible to obtain. Nonetheless, it is apparent from the data in Tables 5 and 6 that the prognosis of unilateral lesions is better than that of the more extensive posterior or bilateral lesions. The only tumor-related deaths occurred in those patients who had undergone no excision or incomplete excision of their tumors. It is important to emphasize that the indications for surgery in reports of surgically treated patients determine the patient population and the category of disease treated. Those patients reported who have been followed without therapy of any kind obviously had very benign forms of optic glioma (only 19 of the 36 cases of Hoyt and Baghdassarian 2~ had visual symptoms referable to the optic glioma). In our series, anterior lesions were operated on usually only when progressive proptosis and visual loss were present. Proptosis was considered an indication for surgery when it produced pain, jeopardized the health of the cornea or the globe, or was a major cosmetic problem. In the majority of cases, the globe was preserved2 The majority of surgically treated posterior lesions had significant mass effect, with many causing obstructive hydrocephalus, and fre- 56 J. Neurosurg. / Volume 57/October, 1982

6 Management of optic gliomas quently there was significant question as to the correct diagnosis. For practical purposes, we believe that any unilateral resectable tumor should be removed, assuming that vision is severely compromised. We continue to follow conservatively some patients in whom vision is preserved and proptosis is minimal. Posterior and bilateral lesions are treated by radiation therapy, usually after surgical exploration; tumor resection is performed as necessary to relieve obstructive hydrocephalus, and biopsy of smaller lesions is carried out when the biopsy would not further jeopardize the remaining vision. No patient in our series suffered loss of vision secondary to biopsy of a posterior lesion. Current recommendations for radiation therapy to the mature brain consist of a tumor dose of 5000 to 5500 rads, given in fractions not to exceed 180 rads/day, with careful planning of radiation fields so that a generalized radiation effect on the brain can be avoided. With intelligent and appropriate therapy, favorable long-term results can be obtained in approximately 80% of patients with anterior lesions and in just over 50% of those with posterior lesions. Acknowledgment The authors are grateful to Mrs. Constance B. Hoeft for her expert assistance in the preparation of the manuscript. References 1. Baker HL Jr, Kearns TP, Campbell JK, et al: Computerized transaxial tomography in neuro-ophthalmology. Am J Ophthalmoi 78:285-29, Benedict WL: Surgical treatment of tumors and cysts of the orbit. The eleventh de Schweinitz Lecture. Am J Ophthalmol 32: , Bucy PC, Russell JR, Whitsell FM: Surgical treatment of tumors of the optic nerve. Report of a case. Arch Ophthalmo1:11-18, Byers WGM: Primary intradural tumors of the optic nerve: fibromatosis nervi optici. Stud R Victoria Hosp 1:3-82, Byrd SE, Hardwood-Nash DC, Fitz CR, et al: Computed tomography of intraorbital optic nerve gliomas in children. 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7 R. T. Tenny, E. R. Laws, Jr., B. R. Younge and J. A. Rush gliomas, in Thomas DGT, Graham DI (eds): Brain Tumours: Scientific Basis, Clinical Investigation and Current Therapy. London/Boston: Butterworths, 1980, pp Miller NR, IliffWJ, Green WR: Evaluation and management of gliomas of the anterior visual pathways. Brain 97:73-75, Montgomery AB, Griffin T, Parker RG, et al: Optic nerve glioma: the role of radiation therapy. Cancer 0: , Oxenhandler DC, Sayers MP: The dilemma of childhood optic gliomas. J Neurosurg 8:3-1, Parsons JH: The Pathology of the Eye. London: Harden and Stoughten, 1905, Vol 2 1. Pfaffenbach DD, Kearns TP, Hollenhorst RW: An unusual case of optic nerve-chiasmal glioma. Am J Ophthalmol 7: , Posner M, Horrax G: Tumors of the optic nerve. Long survival in three cases of intracranial tumor. Arch Ophthalmol 0:56-76, Rand CW, Irvine R, Reeves DL: Primary glioma of the optic nerve. Report of a case. Arch Ophthalmol 21: , Ray BS: Surgical lesions of the optic nerves and chiasm in infants and children, in Smith JL (ed): Neuro-ophthalmology. St Louis: CV Mosby, 1967, Vol 3, pp Richards RD, Lynn JR: The surgical management of gliomas of the optic nerve. Am J Ophthalmo162:60-65, Rucker CW: Tumors of region of optic chiasm. Collect Papers Mayo Clin :39-351, Sigurjonsdottir TJ, Hayles AB: Precocious puberty. A report of 96 cases. Am J Dis Child 115: , Smigiel MR, MacCarty CS: Exophthalmos. The more commonly encountered neurosurgical lesions. Mayo Clin Proc 50:35-355, Spencer WH: Primary neoplasms of the optic nerve and its sheaths: clinical features and current concepts of pathogenetic mechanisms. Trans Am Ophthalmol Soc 70:90-528, Stern J, Jakobiec FA, Housepian EM: The architecture of optic nerve gliomas with and without neurofibromatosis. Arch Ophthalmo198: , Taveras JM, Mount LA, Wood EH: The value of radiation therapy in the management of glioma of the optic nerves and chiasm. Radiology 66: , Throuvalas N, Baraini P, Ennuyer A: Les gliomes du chiasma et du nerfoptique. L'apport de la radioth~rapie transcutan6e dans leur traitement. Bull Cancer 56: , Udvarhelyi GB: Neurosurgical diagnosis and treatment of lesions involving the anterior visual pathways, in Burde RM, et al (eds): Symposium on Neuroophthalmology, New Orleans, St Louis: CV Mosby, 1976, pp Udvarhelyi GB, Khodadoust AA, Walsh FB: Gliomas of the optic nerve and chiasm in children: an unusual series of cases. Clin Neurosurg 13:20-237, Van Buren JM, Poppen JL, Horrax G: Unilateral exophthalmos. A consideration of symptom pathogenesis. Brain 80: , Verhoeff FH: Primary intraneural tumors (gliomas) of the optic nerve. A histologic study of eleven cases, including a case showing cystic involvement of the optic disk, with demonstration of the origin of cytoid bodies of the retina and cavernous atrophy of the optic nerve. Arch Ophthalmo151:120-10, ; Visot A, Rougerie J, Derome P J, et al: [Optic chiasm gliomas.] Neurochirurgie 26: , 1980 (Fre) 58. Wagener HP: Gliomas of the optic nerve. Am J Med Sci 237: , Walsh FB: The ocular signs of tumors involving the anterior visual pathways. The tenth Francis I. Proctor Lecture. Am J Ophthalmol 2:37-377, Walsh FB, Hoyt WF: Clinical Neuro-Ophthaimology, ed 3. Baltimore: Williams and Wilkins, 1969, Vol 3, pp Wishart JH: Case of extirpation of the eyeball. Edinburgh Med Surg J 0:27-276, Wong IG, Lubow M: Management of optic glioma of childhood: review of 2 cases. Neuroophthalmology 6:51-60, Wright JE, McDonald WI, Call NB: Management of optic nerve gliomas. Br J Ophthalmo16:55-552, Zulch KJ, Nover A: Die Spongioblastome des Sehneryen. Graefe Arch Ophthalmol 161:05-19, 1960 Manuscript received December 23, Accepted in final form May 28, Address reprint requests to: Edward R. Laws, Jr., M.D., Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota J. Neurosurg. / Volume 57 / October, 1982