Giant suprasellar aneurysm associated with optic stalk agenesis and unilateral anophthalmos Case report JULIAN HOFF, M.D., DAVID WINESTOCK, M.D., AND WILLIAM F. HOYT, M.D.
Departments of Neurological Surgery, Radiology, and Ophthalmology, University of California, San Francisco, California The authors report a patient with unilateral anophthalmos who had a large suprasellar aneurysm associated with aplasia of an optic nerve and the chiasmal commissure. The anatomical findings at craniotomy are described. KEY WORDS 9 optic nerve 9 optic c h i a s m anomaly 9 microphthalmia 9 aneurysm
ONGENITAL absence of an optic nerve and chiasmal commissure is one of the developmental consequences of agenesis or regression of an optic stalk. These anomalies of the anterior visual system have been reported in necropsy specimens, 5'6''-1' but their appearance at operation has not been recorded. This report describes the anatomical observations during craniotomy in a patient with unilateral anophthalmos who had a large suprasellar aneurysm associated with aplasia of an optic nerve and the chiasmal commissure.
C
C a s e Report
A 49-year-old man with anophthalmos on the right was admitted to San Francisco General Hospital with complaints of headache, memory loss, and unsteadiness. Examination. Vision in his only eye (the left) was 20/40, with defective color percepJ. Neurosurg. / Volume 43 / October, 1975
9
tion and a total temporal hemanopia. The eye was of normal size, moved fully in all directions, and exhibited constant horizontal nystagmus of irregular amplitude that increased in gaze toward the right. The nystagmus remained horizontal during upward and downward gaze and was not influenced by gaze at a nearby object. Pupillary reactions of the eye were normal in response to light and accommodative stimuli. The ocular media were clear. There was no retinopathy and the retinal vessels appeared normal. The optic disc was abnormally small, slightly pale temporally, fiat without an optic cup, and vertically oval with the retinal vessels emerging from its nasal margin at 9 o'clock. The nerve fiber layer surrounding the disc was abnormally thinned in the upper and lower sectors and absent in the temporal and nasal sectors. These changes in the disc and the peripapillary nerve fibers were consistent with hemioptic hypoplasia described in patients 495
J. Hoff, D. Winestock and W. F. Hoyt
FIG. 1. Pneumoencephalogram, parasellar tomography. A suprasellar mass with a partially calcified rim is demonstrated (arrows).
with congenital hemiplegia by Hoyt, et aL 7 Examination of the ocular adenexa in the anophthalmic orbit showed the expected appearance of enophthalmos with a small palpebral fissure. In the depths of the conjunctival sac was a small firm nodule of white tissue that might have contained congenital remnants of neuroectodermal tissue. This nodule moved back and forth in apparent synchrony with the horizontal movements of the left eye. Neurological examination confirmed a moderate defect in recent memory, a broadbased ataxic gait, and absent position and vibratory sensation with loss of deep tendon
reflexes distally in the arms and legs. There were no signs of pituitary insufficiency. The clinical diagnoses were chiasmal syndrome of uncertain etiology, congenital absence of the right eye, and peripheral neuropathy from chronic alcoholism. Neuroradiological investigations revealed a normal-sized right orbit, a tiny (2 mm) optic foramen on the right, and a curvilinear calcification above a normal-appearing sella. Pneumoencephalography showed a round filling defect in the suprasellar cisterns (Fig. 1). This filling defect caused a smoothly curved convex indentation in the anterior inferior third ventricle. The optic and infundibular recesses and the chiasmal commissure could not be identified. The suprasellar filling defect obscured all signs of the optic nerves in the suprasellar area. Selective internal carotid angiography showed a narrow ophthalmic artery and no choroidal crescent on the right. The left internal carotid study showed a normal ophthalmic artery and choroidal crescent and a suprasellar aneurysm originating from the left anterior cerebral artery. The aneurysm had an irregular, elongated, inferiorly-pointing lumen that was smaller than the mass which was demonstrated by the pneumoencephalogram (Fig. 2 left). Vertebral injections opacified normalappearing basilar and posterior cerebral arteries. Asymmetry of the size of the occipital lobes or their vascularity could not be detected either by angiography or air study. Operation. After the patient's peripheral neuropathy had improved, the suprasellar
FIG. 2. Left internal carotid arteriogram, frontal view. The aneurysm is shown before clipping (left) and after clipping (right). 496
d. Neurosurg. / Volume 43 / October, 1975
Optic stalk agenesis with suprasellar aneurysm
FtG. 3. Artist's conception of suprasellar aneurysm and anomalous chiasm and optic nerve, drawn from operative sketches. region was explored with the intention of clipping and resecting the aneurysm. At craniotomy the left optic nerve was identified first at the optic foramen. It appeared healthy but was abnormally small in diameter and was deflected upward and laterally by a midline mass (Fig. 3). The left ophthalmic artery arose 1 cm distal to the dural entry of the carotid artery into the cranial cavity. It entered the left optic foramen beneath the optic nerve. Posteriorly the left optic nerve passed directly into the left optic tract as a single pathway without a vestige of a chiasm. Filmy arachnoid adhesions formed a bridge between this nondecussating optic "nerve" and the mass. The aneurysmal mass was firm, immobile, and yellow without attachment to the carotid trunks or the right anterior cerebral artery. The right ophthalmic artery also arose 1 cm beyond the point where the right internal carotid artery entered the cranial vault and coursed anteriorly alone into the tiny right optic foramen. The tuberculum sellae, planum sphenoidale, anterior clinoid processes, and sphenoid wings appeared normal. An atherosclerotic neck of the aneurysm was identified at the portion of the left anterior cerebral artery adjacent to its junction with the anterior communicating artery. A clip was applied across the neck and the fundus of the aneurysm was resected. At this point in the operation the lamina terminalis of the anterior third ventricle was visible as a J. Neurosurg. / Volume 43 / October, 1975
thin-walled midline structure that did not contain any recognizable chiasmal commissure. A compressed infundibular stalk marked the posterior limit of the chiasm-free wall of the third ventricle. Histopathological examination of the mass confirmed its vascular origin. Postoperative Course. After operation the patient recovered promptly. Angiography on the tenth day after operation showed no evidence of the aneurysmal sac (Fig. 2 right). Three weeks thereafter the patient was transferred to a special facility for alcoholics. Discussion The optic vesicles, from which the eyes and their optic nerves develop, appear during the neural-plate stage of embryogenesis, in the third week after conception. 1 Experimentally, failure of vesicle formation or destruction of the vesicle from effects of toxins, infection, anoxia, or trauma, causes anophthalmos or severe microphthalmos with associated aplasia of the optic pathways.8'8 Clinically, causes of these optic vesicle defects are seldom defined, though heredity accounts for some. 10 Mann 8 distinguished three forms of anophthalmia: a primary form in which there is failure of formation of the optic vesicle from the anterior end of the neural tube, a secondary form resulting from developmental abnormality of the whole of the forebrain, 497
J. Hoff, D. Winestock and W. F. Hoyt and a degenerative form in which the optic that both resulted from a single teratogenic vesicles regress and disappear completely. event affecting cell differentiation in the first The degenerative form merges imperceptibly weeks of gestation. with severe forms of microphthalmos in References which the eye is no more than a nodule of connective tissue containing a few nests of un1. Barber AN, Ronstrom AN, Muelling RJ Jr: differentiated neuroepithelial cells. All forms Development of the visual pathway: optic of bilateral anophthalmos are associated with chiasm. Arch Ophthaimol 52:447-453, 1954 2. Carmichael R: The pathogenesis of nonabsence of optic nerves, chiasm, optic tracts, inflammatory cerebral aneurysms. J Pathoi and with gross anomalies of the genieBact 62:1-19, 1950 ulostriate system? 3. Duke-Elder WS (ed): System of OphthUnilateral anophthalmos, depending on its almology, Vol 3, Parts 1 & 2. St Louis, CV cause, may be associated with partial or total Mosby, 1963 absence of the chiasmal commissure. If 4. Forbus WD: On the origin of miliary growth of ganglion cell projections from the aneurysms of the superficial cerebral arteries. normal eye proceeds centrally without imBull Johns Hopkins Hosp 47:239-284, 1930 pediment to decussation through the 5. Haberland C, Perou M: Primary bilateral forebrain anlage of the chiasmal commissure, anophthalmia. J Neuropathol Exp Neurol the patient will have both crossed and un28:337-350, 1969 6. Hare R: Congenital bilateral anophthalmos. crossed visual projections to the brain. The Arch Ophthalmol 30:320-330, 1943 chiasm will then be hypoplastic. 12 If decussa7. Hoyt WF, RiosMontenegro EN, Behrens tion of ingrowing visual fibers from the norMM, et al: Homonymous hemioptic hymal eye is blocked by the forebrain abnorperplasia: fundoscopic features in standard mality that caused arrest of one optic vesicle, and red-free illumination in three patients with or if these decussating fibers degenerate after congenital hemiplegia. Br J Ophthaimol embryonic injury to the optic pathway above 56:537-545, 1972 the chiasm, the patient will have only an un8. Mann I: Developmental Anomalies of the Eye. crossed, or ipsilaterally projecting, visual London, British Medical Association, 1957, system that operates through afferent p 419 9. Padget DH: The development of the cranial hemianopic projections to one occipital lobe. arteries in the human embryo. Contrih EmIn this circumstance unilateral anophthalmos hryoi 32:205-262, 1948 and optic nerve agenesis may be associated with agenesis of the chiasmal commissure and 10. Patau K, Smith DW, Therman E, et al: Multiple congenital anomaly caused by an extra retrograde hemioptic hypoplasia of the funcautosome. Lancet 1:790-793, 1960 tioning optic nerve. 7 Additional visual sys- 11. Recordan E, Griftiths GM: A case of primary tem anomalies may include absence of a bilateral anophthalmia. (Clinical and hisrecognizable lateral geniculate nucleus on the tological report.) Br J Ophthalmol 22: functioning side, and aplasia of the striate 353-360, 1938 cortex in the blind occipital lobe. 5 Our patient 12. Rogalski T: The visual paths in a case of unilateral anophthalmia with special reference to had unilateral anophthalmos with chiasmal the problem of crossed and uncrossed visual agenesis. While we believe that his optic vesifibres. J Anat (Lond) 80:153-159, 1940 cle formed initially and then degenerated, our 13. Sacks JG, Lindenberg R: Efferent nerve conclusions are speculative. fibers in the anterior visual pathways in Congenital cerebral aneurysms may arise bilateral congenital cystic eyeballs. Am J soon after mesodermal elements become Ophthaimol 68:691-695, 1970 tubular structures. 4 The internal carotid 14. Warfel JH: A case of unilateral degenerative arteries can be recognized in the embryo as anophthalmia. Am J Ophthalmoi 51:698-701, early as the fourth week of gestation; com1961 ponents of the circle of Willis usually appear by the sixth week. 2'9 Our patient's aneurysm This work was supported in part by USPHS was saccular with a well-formed neck and a Grants GM 18470, NS 11539, and EY-00083-01. normal parent vessel, the anterior cerebral Dr. Hoff was a recipient of Teacher-Investigator artery. These facts strongly suggest its con- Award NS 11051 NSRB. genital origin. Despite the juxtaposition of Address reprint requests to: Julian Hoff, M.D., vascular and optic anomalies in our patient, Department of Neurosurgery, University of we cannot support or reject the possibility California, San Francisco, California 94143. J. Neurosurg. / Volume 43 / October, 1975 498
Departments of Neurological Surgery, Radiology, and Ophthalmology, University of California, San Francisco, California The authors report a patient with unilateral anophthalmos who had a large suprasellar aneurysm associated with aplasia of an optic nerve and the chiasmal commissure. The anatomical findings at craniotomy are described. KEY WORDS 9 optic nerve 9 optic c h i a s m anomaly 9 microphthalmia 9 aneurysm
ONGENITAL absence of an optic nerve and chiasmal commissure is one of the developmental consequences of agenesis or regression of an optic stalk. These anomalies of the anterior visual system have been reported in necropsy specimens, 5'6''-1' but their appearance at operation has not been recorded. This report describes the anatomical observations during craniotomy in a patient with unilateral anophthalmos who had a large suprasellar aneurysm associated with aplasia of an optic nerve and the chiasmal commissure.
C
C a s e Report
A 49-year-old man with anophthalmos on the right was admitted to San Francisco General Hospital with complaints of headache, memory loss, and unsteadiness. Examination. Vision in his only eye (the left) was 20/40, with defective color percepJ. Neurosurg. / Volume 43 / October, 1975
9
tion and a total temporal hemanopia. The eye was of normal size, moved fully in all directions, and exhibited constant horizontal nystagmus of irregular amplitude that increased in gaze toward the right. The nystagmus remained horizontal during upward and downward gaze and was not influenced by gaze at a nearby object. Pupillary reactions of the eye were normal in response to light and accommodative stimuli. The ocular media were clear. There was no retinopathy and the retinal vessels appeared normal. The optic disc was abnormally small, slightly pale temporally, fiat without an optic cup, and vertically oval with the retinal vessels emerging from its nasal margin at 9 o'clock. The nerve fiber layer surrounding the disc was abnormally thinned in the upper and lower sectors and absent in the temporal and nasal sectors. These changes in the disc and the peripapillary nerve fibers were consistent with hemioptic hypoplasia described in patients 495
J. Hoff, D. Winestock and W. F. Hoyt
FIG. 1. Pneumoencephalogram, parasellar tomography. A suprasellar mass with a partially calcified rim is demonstrated (arrows).
with congenital hemiplegia by Hoyt, et aL 7 Examination of the ocular adenexa in the anophthalmic orbit showed the expected appearance of enophthalmos with a small palpebral fissure. In the depths of the conjunctival sac was a small firm nodule of white tissue that might have contained congenital remnants of neuroectodermal tissue. This nodule moved back and forth in apparent synchrony with the horizontal movements of the left eye. Neurological examination confirmed a moderate defect in recent memory, a broadbased ataxic gait, and absent position and vibratory sensation with loss of deep tendon
reflexes distally in the arms and legs. There were no signs of pituitary insufficiency. The clinical diagnoses were chiasmal syndrome of uncertain etiology, congenital absence of the right eye, and peripheral neuropathy from chronic alcoholism. Neuroradiological investigations revealed a normal-sized right orbit, a tiny (2 mm) optic foramen on the right, and a curvilinear calcification above a normal-appearing sella. Pneumoencephalography showed a round filling defect in the suprasellar cisterns (Fig. 1). This filling defect caused a smoothly curved convex indentation in the anterior inferior third ventricle. The optic and infundibular recesses and the chiasmal commissure could not be identified. The suprasellar filling defect obscured all signs of the optic nerves in the suprasellar area. Selective internal carotid angiography showed a narrow ophthalmic artery and no choroidal crescent on the right. The left internal carotid study showed a normal ophthalmic artery and choroidal crescent and a suprasellar aneurysm originating from the left anterior cerebral artery. The aneurysm had an irregular, elongated, inferiorly-pointing lumen that was smaller than the mass which was demonstrated by the pneumoencephalogram (Fig. 2 left). Vertebral injections opacified normalappearing basilar and posterior cerebral arteries. Asymmetry of the size of the occipital lobes or their vascularity could not be detected either by angiography or air study. Operation. After the patient's peripheral neuropathy had improved, the suprasellar
FIG. 2. Left internal carotid arteriogram, frontal view. The aneurysm is shown before clipping (left) and after clipping (right). 496
d. Neurosurg. / Volume 43 / October, 1975
Optic stalk agenesis with suprasellar aneurysm
FtG. 3. Artist's conception of suprasellar aneurysm and anomalous chiasm and optic nerve, drawn from operative sketches. region was explored with the intention of clipping and resecting the aneurysm. At craniotomy the left optic nerve was identified first at the optic foramen. It appeared healthy but was abnormally small in diameter and was deflected upward and laterally by a midline mass (Fig. 3). The left ophthalmic artery arose 1 cm distal to the dural entry of the carotid artery into the cranial cavity. It entered the left optic foramen beneath the optic nerve. Posteriorly the left optic nerve passed directly into the left optic tract as a single pathway without a vestige of a chiasm. Filmy arachnoid adhesions formed a bridge between this nondecussating optic "nerve" and the mass. The aneurysmal mass was firm, immobile, and yellow without attachment to the carotid trunks or the right anterior cerebral artery. The right ophthalmic artery also arose 1 cm beyond the point where the right internal carotid artery entered the cranial vault and coursed anteriorly alone into the tiny right optic foramen. The tuberculum sellae, planum sphenoidale, anterior clinoid processes, and sphenoid wings appeared normal. An atherosclerotic neck of the aneurysm was identified at the portion of the left anterior cerebral artery adjacent to its junction with the anterior communicating artery. A clip was applied across the neck and the fundus of the aneurysm was resected. At this point in the operation the lamina terminalis of the anterior third ventricle was visible as a J. Neurosurg. / Volume 43 / October, 1975
thin-walled midline structure that did not contain any recognizable chiasmal commissure. A compressed infundibular stalk marked the posterior limit of the chiasm-free wall of the third ventricle. Histopathological examination of the mass confirmed its vascular origin. Postoperative Course. After operation the patient recovered promptly. Angiography on the tenth day after operation showed no evidence of the aneurysmal sac (Fig. 2 right). Three weeks thereafter the patient was transferred to a special facility for alcoholics. Discussion The optic vesicles, from which the eyes and their optic nerves develop, appear during the neural-plate stage of embryogenesis, in the third week after conception. 1 Experimentally, failure of vesicle formation or destruction of the vesicle from effects of toxins, infection, anoxia, or trauma, causes anophthalmos or severe microphthalmos with associated aplasia of the optic pathways.8'8 Clinically, causes of these optic vesicle defects are seldom defined, though heredity accounts for some. 10 Mann 8 distinguished three forms of anophthalmia: a primary form in which there is failure of formation of the optic vesicle from the anterior end of the neural tube, a secondary form resulting from developmental abnormality of the whole of the forebrain, 497
J. Hoff, D. Winestock and W. F. Hoyt and a degenerative form in which the optic that both resulted from a single teratogenic vesicles regress and disappear completely. event affecting cell differentiation in the first The degenerative form merges imperceptibly weeks of gestation. with severe forms of microphthalmos in References which the eye is no more than a nodule of connective tissue containing a few nests of un1. Barber AN, Ronstrom AN, Muelling RJ Jr: differentiated neuroepithelial cells. All forms Development of the visual pathway: optic of bilateral anophthalmos are associated with chiasm. Arch Ophthaimol 52:447-453, 1954 2. Carmichael R: The pathogenesis of nonabsence of optic nerves, chiasm, optic tracts, inflammatory cerebral aneurysms. J Pathoi and with gross anomalies of the genieBact 62:1-19, 1950 ulostriate system? 3. Duke-Elder WS (ed): System of OphthUnilateral anophthalmos, depending on its almology, Vol 3, Parts 1 & 2. St Louis, CV cause, may be associated with partial or total Mosby, 1963 absence of the chiasmal commissure. If 4. Forbus WD: On the origin of miliary growth of ganglion cell projections from the aneurysms of the superficial cerebral arteries. normal eye proceeds centrally without imBull Johns Hopkins Hosp 47:239-284, 1930 pediment to decussation through the 5. Haberland C, Perou M: Primary bilateral forebrain anlage of the chiasmal commissure, anophthalmia. J Neuropathol Exp Neurol the patient will have both crossed and un28:337-350, 1969 6. Hare R: Congenital bilateral anophthalmos. crossed visual projections to the brain. The Arch Ophthalmol 30:320-330, 1943 chiasm will then be hypoplastic. 12 If decussa7. Hoyt WF, RiosMontenegro EN, Behrens tion of ingrowing visual fibers from the norMM, et al: Homonymous hemioptic hymal eye is blocked by the forebrain abnorperplasia: fundoscopic features in standard mality that caused arrest of one optic vesicle, and red-free illumination in three patients with or if these decussating fibers degenerate after congenital hemiplegia. Br J Ophthaimol embryonic injury to the optic pathway above 56:537-545, 1972 the chiasm, the patient will have only an un8. Mann I: Developmental Anomalies of the Eye. crossed, or ipsilaterally projecting, visual London, British Medical Association, 1957, system that operates through afferent p 419 9. Padget DH: The development of the cranial hemianopic projections to one occipital lobe. arteries in the human embryo. Contrih EmIn this circumstance unilateral anophthalmos hryoi 32:205-262, 1948 and optic nerve agenesis may be associated with agenesis of the chiasmal commissure and 10. Patau K, Smith DW, Therman E, et al: Multiple congenital anomaly caused by an extra retrograde hemioptic hypoplasia of the funcautosome. Lancet 1:790-793, 1960 tioning optic nerve. 7 Additional visual sys- 11. Recordan E, Griftiths GM: A case of primary tem anomalies may include absence of a bilateral anophthalmia. (Clinical and hisrecognizable lateral geniculate nucleus on the tological report.) Br J Ophthalmol 22: functioning side, and aplasia of the striate 353-360, 1938 cortex in the blind occipital lobe. 5 Our patient 12. Rogalski T: The visual paths in a case of unilateral anophthalmia with special reference to had unilateral anophthalmos with chiasmal the problem of crossed and uncrossed visual agenesis. While we believe that his optic vesifibres. J Anat (Lond) 80:153-159, 1940 cle formed initially and then degenerated, our 13. Sacks JG, Lindenberg R: Efferent nerve conclusions are speculative. fibers in the anterior visual pathways in Congenital cerebral aneurysms may arise bilateral congenital cystic eyeballs. Am J soon after mesodermal elements become Ophthaimol 68:691-695, 1970 tubular structures. 4 The internal carotid 14. Warfel JH: A case of unilateral degenerative arteries can be recognized in the embryo as anophthalmia. Am J Ophthalmoi 51:698-701, early as the fourth week of gestation; com1961 ponents of the circle of Willis usually appear by the sixth week. 2'9 Our patient's aneurysm This work was supported in part by USPHS was saccular with a well-formed neck and a Grants GM 18470, NS 11539, and EY-00083-01. normal parent vessel, the anterior cerebral Dr. Hoff was a recipient of Teacher-Investigator artery. These facts strongly suggest its con- Award NS 11051 NSRB. genital origin. Despite the juxtaposition of Address reprint requests to: Julian Hoff, M.D., vascular and optic anomalies in our patient, Department of Neurosurgery, University of we cannot support or reject the possibility California, San Francisco, California 94143. J. Neurosurg. / Volume 43 / October, 1975 498
