Technical note: Endoscopic resection of a dermoid cyst anchored to the anterior optic chiasm

Introduction: Supratentorial dermoid cysts arise due to the misplacement of embryonic inclusions in the vicinity of the developing neural tube up to the third week of life, when the neural groove begins to close. This report describes a case of a suprasellar dermoid cyst anchored to the anterior optic chiasm, which was accurately located by endoscopic observation, removed gross-totally without visual disturbance, and confirmed pathologically. Although the cyst wall was gross-totally resected, the patient’s impaired visual field returned to a normal level. The resection procedure under endoscopic vision is demonstrated. Materials and Methods: A 22-year-old man gradually developed bitemporal hemianopsia with retrobulbar pain over two months. Magnetic resonance imaging demonstrated a suprasellar cyst with intracystic fat contents forming a fluid level within the lesion. The suprasellar cyst was gross-totally removed with endoscopic endonasal transsphenoidal procedures. Intraoperative inspection confirmed that this cyst arose from the optic chiasm. Pathological examination showed the lesion as a dermoid cyst. Results: After gross-totally resection of the cyst, the patient presented a further, transient impairment of bitemporal hemianopsia; at four month follow-up, his visual disturbance was not evident any longer. Conclusion: To the best of our knowledge, ours is the only case of a dermoid cyst anchored to the anterior optic chiasma, which was visually confirmed under endoscopic observation. After surgery, the patient presented a transient impairment of the visual field, which was not evident at four month follow-up. It will contribute to a similar case, in which surgeons hesitate to make an incision in the optic chiasm. A subtotal excision should be considered in cases of dermoid cysts anchored to the anterior optic chiasm, because all the previously reported cases of suprasellar dermoid cysts are young people or those who have a relatively long life expectancy.