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Show ORIGINAL CONTRIBUTION Intrachiasmal Craniopharyngioma: Treatment with a Cisternal Catheter Drainage and Radiation Howard D. Pomeranz, MD, PhD and E. Francois Aldrich, MD Abstract: A 54- year- old woman who presented with headaches and bitemporal visual field loss had an MRI that disclosed a cystic lesion within the optic chiasm. Craniotomy yielded an inconclusive biopsy; incisional decompression of the cyst provided only temporary improvement in vision. When vision declined 3 months later, an MRI showed recurrence of the cyst. The patient underwent a second craniotomy with biopsy that revealed an adamanti-nomatous craniopharyngioma. Because of the dangers of surgical removal, the cyst was left in place and connected by catheter to the prechiasmatic cisternal subarachnoid space. She received 54 Gy of three- dimensional conformal x- irradiation. At the time of her last follow- up examination 28 months postoperatively, the patient had marked improvement in her visual acuity and visual fields; an MRI demonstrated that the cyst remained decompressed. Cisternal catheter drainage represents a novel approach to the treatment of this rare variant of craniopharyngioma. ( JNeuro- Ophthalmol 2004; 24: 27- 30) ntrachiasmal craniopharyngioma is a rare cause of chiasmal enlargement. Two cases have been described by Duff and Levine ( 1) and Brodsky et al. ( 2). Both showed bilobed thickening of the chiasm with a " potbelly" expansion of the contiguous optic nerves on imaging. They were treated with total or partial resection to relieve compression on the chiasm and optic nerves. This report describes a patient with a From the Department of Ophthalmology ( HDP), University of Minnesota Medical School, Minneapolis, Minnesota; and the Department of Neurosurgery ( EFA), University of Maryland School of Medicine, Baltimore, Maryland. Address correspondence to Howard Pomeranz, MD, PhD, University of Minnesota Medical School, Department of Ophthalmology, MMC 493, 420 Delaware Street SE, Minneapolis, MN 55455. E- mail: pomer010@ umn. edu There are no affiliations with any organizations or entities with direct financial interest in the subject matter or materials discussed in the manuscript. Supported in part by an unrestricted grant from the Research to Prevent Blindness, Inc., New York, New York to the Department of Ophthalmology at the University of Minnesota Medical School. cystic intrachiasmal craniopharyngioma managed by decompression with an indwelling cisternal catheter followed by radiation therapy. CASE REPORT A 54- year- old woman developed headaches and loss of peripheral vision over 6 months. An ophthalmologist documented bitemporal visual field loss. MRI revealed a lobulated, thin walled cystic mass in the suprasellar region with a thin margin of enhancement measuring approximately 25 mm in maximum oblique dimension; the cyst appeared to be located immediately below the optic chiasm or within it ( Fig. 1). The patient underwent biopsy of the mass through a fronto- temporal craniotomy, but the pathology was inconclusive. The cyst was incised at the thinnest portion of the chiasm, and excellent decompression of the chiasm was observed. Because of a presumed diagnosis of pilocytic astrocytoma and postoperative improvement, no radiation was given. On neuro- ophthalmologic examination 5 weeks after the craniotomy, visual acuity was OD 5/ 200 and OS 20/ 40. Visual field testing revealed inferotemporal field loss in the OS and inferotemporal field loss as well as a central scotoma in the OD ( Fig. 2). There was increased cupping of the right optic nerve compared with the left optic nerve without pallor. Neurological examination was normal. The patient returned 13 weeks after the craniotomy complaining of difficulty reading. Visual acuities were OD 5/ 200 and OS 20/ 400. Visual fields disclosed denser temporal field loss bilaterally ( Fig. 3). MRI showed recurrence and enlargement of the cyst. A repeat right fronto- temporal craniotomy revealed an enlarged chiasm. On its superior aspect, where it was thinnest, the cyst was re- opened. Straw- colored fluid under pressure escaped and allowed immediate decompression of the chiasm. Extensive micro- dissection around the optic nerves, optic chiasm, and opening of the lamina terminalis to allow exploration of the anterior third ventricle failed to reveal any other areas of pathology. Small pieces of white solid substance were harvested from the inferior portion of the cyst and confirmed histologically to be compact " wet J Neuro- Ophthalmol, Vol. 24, No. 1, 2004 27 JNeuro- Ophthalmol, Vol. 24, No. 1, 2004 Pomeranz et al. FIGURE 1. Preoperative MRI. A. Axial T1 enhanced study reveals a cyst in the region of the optic chiasm with " potbelly" extension into the intracranial aspect of both optic nerves ( arrow). B. Coronal T1 study reveals cystic enlargement of the chiasm ( arrow). The contents of the cyst are mildly hyperintense relative to spinal fluid. keratin" ( Fig. 4). A very small biopsy from the wall of the cavity showed squamous epithelium. These features were considered consistent with a diagnosis of adamantinomatous craniopharyngioma. Because drainage of the cyst completely decompressed the FIGURE 2. Goldmann visual fields performed 5 weeks after the initial craniotomy and cyst venting. They reveal bitemporal temporal defects with a dense central scotoma in the OD ( visual acuities were OD 5/ 200 and OS 20/ 40). chiasm, no mass lesion was present, and the cyst wall tightly adhered to the chiasm, no further resection of the craniopharyngioma was attempted. Instead, one end of a small ( 1.5 mm diameter) silicone elastomer tubing ( Met-ronic PS Medical EDM) catheter was placed in the cyst and the other end into the prechiasmal cistern to provide drainage of the cyst into the subarachnoid space. Two weeks after surgery, visual acuities improved to OD 20/ 200 and OS 20/ 30. The patient underwent three-dimensional conformal radiation to the chiasm with 54 Gy of radiation in 30 fractions over 50 days. MRI performed 3 days after the cyst procedure confirmed the position of the catheter and a decrease in the size of the cyst ( Fig. 5). Three months after the cyst procedure, visual acuities were OD 20/ 60 and OS 20/ 25. The visual fields had improved ( Fig. 6). One year after the procedure, an MRI showed that the catheter was in place and the cyst decompressed. Twenty- eight months after the procedure, her visual acuities were OD 20/ 40 and OS 20/ 30. DISCUSSION Craniopharyngiomas constitute between 2.5% and 4% o of all brain tumors ( 3). Although endocrine dysfunction is the major presenting symptom in adults ( decreased sexual drive in men and amenorrhea in women), about 80%> of FIGURE 3. Visual fields performed 1 3 weeks after the initial craniotomy and cyst venting. The bitemporal defects have worsened ( visual acuity had declined to OD 5/ 200 and OS 20/ 400). 28 © 2004 Lippincott Williams & Wilkins Intrachiasmal Craniopharyngioma FIGURE 4. Biopsy of the chiasm from the second craniotomy. It shows stacked arrays of plump necrobiotic squames ( wet keratin), a characteristic feature of the adamantinoma-tous variant of craniopharyngioma. adult patients complain of vision loss ( 4). Chiasmal and optic nerve dysfunction is therefore a common presenting manifestation of suprasellar craniopharyngiomas with superior extension. The tumor causes upward deviation with stretching and thinning of the chiasm. In contrast, true in-trachiasmatic craniopharyngiomas cause bilobed expansion of the chiasm and a " potbelly" enlargement of the optic nerves simulating the appearance of a pilocytic astrocytoma, both radiographically and intraoperatively. True intrachiasmatic craniopharyngiomas are very rare. There have been only three reports in the literature ( 1- 2, 5). Lindenberg et al. ( 5) in 1977 reported a necropsy study of a craniopharyngioma involving the chiasm. The brain contained a large third ventricular tumor that extended anteriorly into the chiasm. The tumor caused bilobed expansion of the chiasm and a " potbelly" enlargement of the optic nerves. Duff and Levine ( 1) reported the first clinical case of intrachiasmatic craniopharyngioma with bitemporal field defects and bilateral visual acuity loss. Computed tomography ( CT) revealed a suprasellar mass, which proved at craniotomy to be an enlarged chiasm. The chiasm was biopsied but not resected. Visual function was unchanged postoperatively. Brodsky et al. ( 2) reported an intrachiasmatic craniopharyngioma with visual acuities of 20/ 20 OD, 20/ 200 OS, a partial temporal hemianopia in the OD, and a central scotoma in the OS. MRI revealed a bilobed enlargement of the chiasm with " potbelly" expansion a few millimeters into the contiguous optic nerves. The tumor was removed piecemeal from the third ventricle and from its anterior extension into the chiasm and optic nerves through an incision made in the lamina terminalis. The patient subsequently recovered to 20/ 20 in both eyes with JNeuro- Ophthalmol, Vol. 24, No. 1, 2004 FIGURE 5. Axial T1 MRI performed 3 days after the second craniotomy and catheter placement. The cyst has been decompressed; the catheter ( arrow) drains into the subarachnoid space of the prechiasmatic cistern. normal visual fields. He received radiation treatment with a total tumor dose of 5500 rads in 30 fractions. Neither of these patients was reported to have developed recurrence of visual symptoms, but the duration of follow- up was not specified. Many intracranial craniopharyngiomas have cystic components that vary from multiple small cysts to single large cystic masses. The cyst walls may vary from thin diaphanous membranes to thick tough structures that may have calcified. The cyst walls often cause an intense glial FIGURE 6. Visual fields performed 12 weeks after the second craniotomy. They show marked improvement ( visual acuities had improved to OD 20/ 60, OS 20/ 25). 29 JNeuro- Ophthalmol, Vol. 24, No. 1, 2004 Pomeranz et al. reaction in the surrounding brain, and aggressive traction and resection of the capsule could lead to hypothalamic or chiasmatic damage ( 6). Given these hazards, various techniques have been proposed for cyst treatment. One approach is aspiration of the cyst with isotope installation, either before radiation therapy or for the treatment of cyst recurrence ( 7- 9). Another approach is placement of an in-tracystic catheter connected to a subcutaneous Ommaya reservoir, which allows multiple aspirations of cyst fluid ( 7). In some cases, this drainage is followed by placement of intracavitary radioactive phosphorus. Although the use of intracavitary radioactive isotopes is a well- established treatment method for large intracranial cysts, it is not recommended for small intrachiasmal cysts, as radioactive phosphorus would damage the anterior visual pathway. The use of a catheter connected to an Ommaya reservoir might not be optimal for an intrachiasmal cyst because of the fear that catheter movement would damage the neural tissue. In our patient, silicone elastomere tubing usually used for lumbo- peritoneal shunting was selected as the drainage system because of its soft texture, small diameter, and low likelihood of kinking and causing obstruction. The rationale for this drainage system was that even if it did not continue to drain permanently, it would keep the cyst decompressed until radiation therapy scarred it down. We were concerned that chemical meningitis might result from spillage or drainage of craniopharyngioma cyst contents into the subarachnoid space, but fortunately our patient did not develop any side effects from cyst drainage, most likely due to the small volume and the dilute nature of the fluid. Our case is the fourth reported example of an intrachiasmal craniopharyngioma, and the first to be treated with a combination of a cyst catheter emptying into the subarachnoid space and radiation. Acknowledgment The authors acknowledge the contributions of Kim-berly A. Gyure, MD, Department of Pathology, University of Maryland School of Medicine for her interpretation of the histology slides. REFERENCES 1. Brodsky MC, Hoyt WF, Barnwell SL, Wilson CB. Intrachiasmatic craniopharyngioma: A rare cause of chiasmal thickening. Case report. JNeurosurg 1988; 68: 300- 2. 2. Duff TA, Levine R. Intrachiasmatic craniopharyngioma. Case report. JNeurosurg 1983; 59: 176- 8. 3. Kernohan JW. Tumors of congenital origin. In: Minckler J, ed. Pathology of the Nervous System, v. 2. New York: McGraw- Hill, 1971: 1927- 37. 4. Carmel PW. Craniopharyngiomas. In: Wilkins RH, Rengachary SS, eds. Neurosurgery, Vol 1. New York: McGraw- Hill, 1985; 905- 16. 5. Lindenberg R, Walsh FB, Sacks JG. Neuropathology of Vision: An Atlas. Philadelphia: Lea & Febiger, 1973; 274- 5. 6. KempeLG. Operative Neurosurgery. Vol. 1. Cranial, Cerebral and Intracranial Vascular Disease. New York: Springer- Verlag, 1968: 90- 3. 7. Backlund EO, Axelsson B, Bergstrand CG, et al. Treatment of craniopharyngiomas: the stereotactic approach in a ten to twenty- three years' perspective. I. Surgical, radiologic and ophfhalmological aspects. Acta Neurochir ( Wien) 1989; 99: 11- 19. 8. Carpenter RC, Chamberlin GW, Frazier CH. The treatment of hypophyseal stalk tumors by evacuation and irradiation. Am J Roentgenology 1937; 38: 162- 77. 9. Julow J, Lanyi F, Hajda M, et al. The radiotherapy of cystic craniopharyngioma with intracystic installation of 90Y silicate colloid. Acta Neurochir ( Wien) 1985; 74: 94- 9. 30 © 2004 Lippincott Williams & Wilkins |
