Osis of the Opposite Eye; (7) Temporal Hemianopsia With

STUDY OF THE PATHOLOGIC CHANGES IN THE OPTIC NERVES AND CHIASM IN COMPARISON WITH CHANGES IN THE VISUAL FIELD IN ASSO- CIATION WITH LARGE PITUITARY TUMORS* WALTER I. LILLIE, M.D. Rochester, Minnesota The ophthalmologic syndromes produced by lesions near -or at the optic chiasm have been well described and definitely established by many authors, but studies of the pathologic changes in the optic nerves and chiasm, and attempts to correlate these with defects in the visual field, are much less numerous. This is true especially when the causative factor is restricted to pituitary tumors. For this reason I studied four cases of extraordinarily large pituitary tumor in which necropsy was performed. These cases were chosen because the bitemporal hemianopic defects in the fields could be correlated with the pathologic changes in the optic nerves and chiasm. The ocular symptoms and signs produced by pituitary tumors may be summarized as follows: (1) Lowered central visual acuity; (2) pallor of the optic discs or simple optic atrophy; (3) bitemporal hemianopsia for various colors or for all colors; (4) bitemporal hemianopsia for form and colors; (5) bitemporal scotomatous hemianopsia for colors or form or for both; (6) temporal hemianopsia with amaurosis of the opposite eye; (7) temporal hemianopsia with successive changes that lead to amaurosis, such as central scotoma, cecocentral scotoma, enlargement of the scotoma, with islets of vision and amaurosis; (8) homonymous herni- * From the Section on Ophthalmology, The Mayo Clinic, Rochester, Minnesota. Candidate's thesis for membership accepted by the Committee on Theses. 15 433 434 LILLIE: Changes in Optic Nerves and Chiasm anopic scotoma for colors or form or for both; (9) homonymous hemianopsia for colors, and (10) homonymous hemianopsia for form and colors. An important feature of the defects in the visual fields produced by pituitary tumors is the asymmetry,-whether bitemporal or homonymous in type,-in contrast to the sym- metrical defects produced by lesions which affect the optic tracts or optic radiations. This can readily be explained by the anatomic variations in the position of the optic chiasm in relation to the pituitary gland. This was reviewed by Fisherand byTraquair, and later summarized and enlarged on by de Schweinitz, who called attention to the thorough anatomic investigations of Schaeffer, which were published later. The earliest visual defects produced by pituitary tumors are found in the cecocentral region. They have been well described by Josefson, Fisher, Traquair, Wilbrand and Saenger, Cushing and Walker, Hill, Ronne, de Schweinitz, and Lillie. These defects have been variously described as "zones of deadened perception," paracentral scotomas, enlarged blind spots, and cecocentral scotomas, but Traquair's expression that the scotomas "behave like the general field" best describes these changes. The behavior of the general field was clearly established by Josefson, Fisher, and Cush- ing and Walker, working independently of one another. Although the central visual pathways were well established by Henschen, it was not until Walker and Cushing made detailed studies of the pathologic changes in the optic nerve that correlation of the defects in the visual field and the pathologic changes in the optic nerve was attempted in chiasmal lesions. Their conclusions were: "1, Despite the so-called atrophic pallor -of the discs in patients having visual-field defects resulting from lesions in the chiasmal regions, the histologic examination of the nerves fails to show the expected degree of fiber degeneration unless the process has been of long duration; 2, the atrophy in the tracts LILLIE: Changes in Optic Nerves and Chiasm 435 considerably antedates that in the nerves, where the fibers. may be preserved by their retinal ganglion cells for several years after complete functional blindness has occurred; 3, our cases serve to illustrate the fact that in the presence of chiasmal pressure of known long duration associated with sharply cut hemianopsias, even when to the ophthalmoscope the nerve shows the pallor of presumed atrophy, there may be no corresponding sharp delineation of the areas of atrophy- in the cross-sections of the nerve; 4, this at first sight wouldt appear to be an inconsistency, but our more accurate perimetric findings with graded discs show that, after all, the boundaries of the seeing areas are less sharply cut than we had previously supposed, and perhaps correspond after all with the diffuse picture in the nerves." The following four cases are reported in an attempt to show that the microscopic changes, in the optic nerves and chiasm, are sufficient that the type of defect in the visual field can be postulated fairly accurately. These changes seem to be due primarily to a definite groove produced by the arteries of the anterior portion of the circle of Willi's, when the pituitary tumor enlarges and displaces the optic chiasm forward and upward. CASE 1.-Chromophobe adenoma of the pituitary gland, inr which the right anterior cerebral artery affected the optic nerves primarily and produced the defects in the visual field. A farmer, aged forty-five years, came for examination because of loss of vision in the right eye of eighteen months' duration, and failing vision in the left eye during the last month. The visual loss had been progressive. The man did not have other complaints. except that he had had headaches, situated in the frontal region,, during the last ten months. The systolic blood-pressure, in millimeters of mercury, was 132, and the diastolic, 90. The basal metabolic rate was -3 per cent. Roentgenographic examination of the teeth revealed two with periapical infection, and there was mild infection of the tonsils. Roentgenograms of the skull gave evidence of enlargement of the 436 LILLIE: Changes in Optic Nerves and Chiasm sella turcica, with calcification of the pineal gland. Ophthalmic examination demonstrated the ability to perceive light with the right eye and to count fingers with the left. The right pupil was larger than the left and did not react to stimulation by direct light, but reacted normally to consensual light. The left pupil reacted promptly to direct light, but there was no response to consensual light. On ophthalmoscopic examination evidence of simple optic atrophy was found in the right eye, and a normal fundus in the left. The perimetric fields revealed the following: a small area in the nasal portion of the field of the right eye that was sensitive to stimulation by light; in the left eye, concentric contraction to form and color, with a large blind spot and small, absolute central scotoma (fig. 1). The neurologic examination gave negative results. A diagnosis of pituitary tumor was made, and at the operation the surgeon found a brownish-green pituitary tumor that was cystic in nature. The cyst rested on the superior aspect of the optic chiasm, and when the tumor was opened, soft, pulpy, reddish- brown material was obtained. A second similar mass was situated in the sella turcica. After the contents had been removed the capsule collapsed, exposing the optic chiasm and both optic nerves. The left optic nerve was fairly well preserved. The right optic nerve was considerably flattened, but removal of the contents of the cyst relieved the nerve of all pressure. The patient's post-operative course was uneventful until the eighth day, when the concentration of urea in the blood increased to 84 mg. in each 100 c.c., and the blood-pressure dropped to 70 systolic and 40 diastolic. The patient died on the tenth day. At necropsy a frontal decompression was noted, with a slight amount of hemorrhage around the operative site. An attempt was made to remove the brain in the usual way, but a large tumor was found projecting from the sella turcica upward toward the third ventricle. The brain was removed, leaving the optic nerves and chiasm attached to the tumor, and a large cavity was found dis- placing the floor of the third ventricle upward. There was only slight evidence of increased intracranial pressure. On examination of the tumor it was seen that the posterior clinoid processes were eroded, displaced, and partly destroyed. The optic nerves were dislocated upward, sharply angulated on -themselves, and pressed between the tumor mass and the superior margin of the orbital foramen. They were flattened and ribbon- .f.E. as.E lop. Does not recognise green color o.e. O.D: Simple optic atrophy 0.8: SNggtive Fig. 1.-Case 1. Temporal hemianopsia of right eye and concentric contraction for form and colors in left eye, associated with absolute central scotoma. Fig. 2.-Case 1. Definite grooving of the right and left optic nerves, just in front of the optic chiasm, by the right anterior cerebral artery. _".40 ... VIO'-~; Iw m" Op Fig. 3.-Case 1. Cross-section of the right optic nerve, revealing destruction of the myelin sheaths. Fig. 4.-Case 1. Cross-section of the left optic nerve, revealing less destruction of the myelin sheaths than in figure 3. Fig. 5.-Case 1. Cross-section of the optic chiasm, which is flattened, and in which there has been considerable destruction of the mvelin sheaths. LILLIE: Changes in Optic Nerves and Chiasm 437 like on their superior surfaces, and there were deep grooves in the nerves where the right anterior cerebral artery had lain (fig. 2). Grooving of the nerves by the artery had destroyed the substance of the nerves, especially the right one. On the right side also the tumor had projected laterally into the Gasserian ganglion, which was much distended and bulged laterally. On longitudinal section through the tumor it was found to have invaded the sphenoid sinus. A large part of the tumor had been removed surgically and had been replaced by blood-clot.

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