Acta Neurochir (Wien) (1995) 134: 167-176 :Acta . . N&Fochirurglca 9 Springer-Verlag 1995 Printed in Austria Gamma Knife Surgery for Craniopharyngioma D. Prasad, M. Steiner, and L. Steiner Department of Neurological Surgery, University of Virginia, Charlottesville, VA, U.S.A. Summary We present our results of Gamma Knife surgery for craniopha- ryngioma in nine patients. The current status of surgery, radiation therapy, intracavitary instillation of radionucleides and Gamma Knife surgery in the management of craniopharyngiomas is dis- cussed. Keywords: Craniopharyngioma; Gamma Knife; radiosurgery. Introduction Benign by nature and uncommon in occurrence, craniopharyngiomas remain a challenging problem for all who have to deal with them. Harvey Cushing considered them 'one of the most baffling of surgical problems'. Furthermore they have always been sur- rounded by controversy, whether it be regarding their origin or their appropriate management. Efforts to achieve a complete resection of these lesions are often hampered by the proximity of structures in the supra- sellar and interpeduncular cisterns, notably the optic pathways, hypothalamus, circle of Willis and the brainstem. Another confounding feature is that approximately 60 percent of these lesions are cystic, with or without a solid component. These cysts behave very differently in response to conventional microsurgical management as compared to the solid tumor. Although numerous surgeons have extolled the virtue in total extirpation of these lesions the recurrence rates reported after occasionally heroic surgical ventures have kept the debate from reaching a conclusion. Current practice includes microsurgery, intracystic instillation of radioisotopes and Gamma Knife surgery for these lesions. We present our experience in Gamma Knife sur- gery of these lesions and review its current place in the management of craniopharyngioma. Patient Material At the University of Virginia, Charlottesville, we have treated nine patients for their craniopharyngiomas with the Gamma Knife between March 1989 and May 1994. Two patients had no prior surgical intervention, two had only stereotactic biopsy and the remaining five had a history of one or more microsurgical resec- tions. Six of the tumors were mixed solid and cystic, and 3 were purely solid. One of the patients was treated four months prior to this writing and had not had a follow-up MRI. Brief case descrip- tions of all nine patients are presented. Case 1 BB, a 57 year old white female who presented with marked decrease in vision and severe headaches of two months duration. She was diagnosed as having a suprasellar solid mass and under- went a craniotomy and subtotal removal of a craniopharyngioma. She had profound dyselectrolytemias following the operation and episodes of cardiac asystole from which she recovered after pro- tracted efforts to correct the electrolyte imbalance. Her vision con- tinued to be poor postoperatively and follow-up MRI revealed an enlarging residual tumor 12 months after the surgery. She under- went Gamma Knife surgery on a residual tumor measuring 16X 16• 13 ram. She received 30 Gy as the maximum dose and the dose delivered to the periphery of the tumor was 10 Gy. The optic pathways received under 5 Gy. Postoperatively she has done very well and has had no dyselectrolytemias. Follow-up MRI at 6 months following the Gamma Knife treatment revealed marked reduction in the tumor size. Patient is doing well and reports improvement in visual acuity. Case 2 GT, a 34 year old male presented with a two and a half year his- tory of decreased visual acuity from a suprasellar lesion. He was unable to perform his duties as a policeman. He underwent place- ment of a VP shunt for hydrocephalus and a stereotactic biopsy, which diagnosed the craniopharyngioma. He was recommended surgery but he refused and chose to undergo Gamma Knife radio- surgery. At the time of Gamma Knife surgery his tumor measured 35X28• mm (Fig. 1). Fifty Gy was given as the maximum dose ant the tumor received 16.7 Gy at the periphery and the optic path-